Ana Aguilar-Paredes, Gabriela Valdés, Nicole Araneda et al.

Agronomy • 2023

Conventional agriculture has important challenges to guarantee soil fertility and sustainable food production. Many agricultural soils in the world are degraded and multiple strategies are currently being developed to restore them. The study of beneficial soil microorganisms has attracted increasing interest due to their relevant role in sustainable agricultural development. The balance and maintenance of ecosystem services, such as biomass transformation, nutrient cycling, plant growth, and health, are directly dependent on soil microbial activity. Therefore, it is important to promote its establishment and propagation. An ancient technique that favors soil biodiversity is the production and application of compost. While numerous studies have focused on the benefits of plant cultivation, fewer studies have focused on the benefits for soil microbiota. The objective of this review was to elucidate the role of the microbiota in the composting process and its impact on soil microorganisms in agriculture. The review presents the advances in the knowledge and importance of microorganisms involved in the composting process and how compost promotes the maintenance and multiplication of beneficial microbial consortia and their ecosystem functions in agricultural soils, shifting towards a more sustainable and resilient agriculture.

B. Asadishad, Shawninder Chahal, A. Akbari et al.

Environmental Science & Technology • 2018

Several types of engineered nanoparticles (ENPs) are being considered for direct application to soils to reduce the application and degradation of pesticides, provide micronutrients, control pathogens, and increase crop yields. This study examined the effects of different metal ENPs and their dissolved ions on the microbial community composition and enzyme activity of agricultural soil amended with biosolids. The activity of five extracellular nutrient-cycling enzymes was measured in biosolid-amended soils treated with different concentrations (1, 10, or 100 mg ENP/kg soil) of silver (nAg), zinc oxide (nZnO), copper oxide (nCuO), or titanium dioxide (nTiO2) nanoparticles and their ions over a 30-day period. At 30 days, nZnO and nCuO either had no significant effect on soil enzyme activity or enhanced enzyme activity. In contrast, Ag inhibited selected enzymes when dosed in particulate or dissolved form (at 100 mg/kg). nTiO2 either had no significant effect or slightly decreased enzyme activity. Illumina MiSeq sequencing of microbial communities indicated a shift in soil microbial community composition upon exposure to high doses of metal ions or nAg and negligible shift in the presence of nTiO2. Some taxa responded differently to nAg and Ag+. This work shows how metal ENPs can impact soil enzyme activity and microbial community composition upon introduction into soils amended with biosolids, depending on their type, concentration, and dissolution behavior, hence providing much needed information for the sustainable application of nanotechnology in agriculture.

P. Naughton, R. Marchant, V. Naughton et al.

Journal of Applied Microbiology • 2019

Synthetic surfactants are becoming increasingly unpopular in many applications due to previously disregarded effects on biological systems and this has led to a new focus on replacing such products with biosurfactants that are biodegradable and produced from renewal resources. Microbially derived biosurfactants have been investigated in numerous studies in areas including: increasing feed digestibility in an agricultural context, improving seed protection and fertility, plant pathogen control, antimicrobial activity, antibiofilm activity, wound healing and dermatological care, improved oral cavity care, drug delivery systems and anticancer treatments. The development of the potential of biosurfactants has been hindered somewhat by the myriad of approaches taken in their investigations, the focus on pathogens as source species and the costs associated with large‐scale production. Here, we focus on various microbial sources of biosurfactants and the current trends in terms of agricultural and biomedical applications.

Aditi Pandit, A. Adholeya, D. Cahill et al.

Journal of Applied Microbiology • 2020

Soil environments are dynamic and the plant rhizosphere harbours a phenomenal diversity of micro‐organisms which exchange signals and beneficial nutrients. Bipartite beneficial or symbiotic interactions with host roots, such as mycorrhizae and various bacteria, are relatively well characterized. In addition, a tripartite interaction also exists between plant roots, arbuscular mycorrhizal fungi (AMF) and associated bacteria. Bacterial biofilms exist as a sheet of bacterial cells in association with AMF structures, embedded within a self‐produced exopolysaccharide matrix. Such biofilms may play important functional roles within these tripartite interactions. However, the details about such interactions in the rhizosphere and their relevant functional relationships have not been elucidated. This review explores the current understanding of naturally occurring microbial biofilms, and their interaction with biotic surfaces, especially AMF. The possible roles played by bacterial biofilms and the potential for their application for a more productive and sustainable agriculture is discussed in this review.

Jingjie Hao, Yen Ning Chai, L. D. Lopes et al.

Applied and Environmental Microbiology • 2020

Determining how microbial properties change across different soils and within the soil depth profile will be potentially beneficial to understanding the long-term processes that are involved in the health of agricultural ecosystems. Most literature on soil microbes has been restricted to the easily accessible surface soils. ABSTRACT This study investigated the differences in microbial community abundance, composition, and diversity throughout the depth profiles in soils collected from corn and soybean fields in Iowa (United States) using 16S rRNA amplicon sequencing. The results revealed decreased richness and diversity in microbial communities at increasing soil depth. Soil microbial community composition differed due to crop type only in the top 60 cm and due to location only in the top 90 cm. While the relative abundance of most phyla decreased in deep soils, the relative abundance of the phylum Proteobacteria increased and dominated agricultural soils below the depth of 90 cm. Although soil depth was the most important factor shaping microbial communities, edaphic factors, including soil organic matter, soil bulk density, and the length of time that deep soils were saturated with water, were all significant factors explaining the variation in soil microbial community composition. Soil organic matter showed the highest correlation with the exponential decrease in bacterial abundance with depth. A greater understanding of how soil depth influences the diversity and composition of soil microbial communities is vital for guiding sampling approaches in agricultural soils where plant roots extend beyond the upper soil profile. In the long term, a greater knowledge of the influence of depth on microbial communities should contribute to new strategies that enhance the sustainability of soil, which is a precious resource for food security. IMPORTANCE Determining how microbial properties change across different soils and within the soil depth profile will be potentially beneficial to understanding the long-term processes that are involved in the health of agricultural ecosystems. Most literature on soil microbes has been restricted to the easily accessible surface soils. However, deep soils are important in soil formation, carbon sequestration, and providing nutrients and water for plants. In the most productive agricultural systems in the United States where soybean and corn are grown, crop plant roots extend into the deeper regions of soils (>100 cm), but little is known about the taxonomic diversity or the factors that shape deep-soil microbial communities. The findings reported here highlight the importance of soil depth in shaping microbial communities, provide new information about edaphic factors that influence the deep-soil communities, and reveal more detailed information on taxa that exist in deep agricultural soils.

R. Seenivasagan, O. Babalola

Biology • 2021

Simple Summary Recently in agriculture, the usage of chemical pesticides and fertilizers has increased tremendously. Additionally, it shows severe effects on human health, ecosystem, and groundwater. Environment-friendly methods are used to improve soil fertility, pests, and disease control. Biopesticide and biofertilizers have the future to upgrade sustainable agriculture for many years. This review highlights the efficacy of biofertilizers and biopesticides in improving crop yielding. It provides an eco-friendly and cost-effective method to get more yield for farmers. It describes the prominence of microbial inoculants in plant cultivation. Abstract Farmers are now facing a reduction in agricultural crop yield, due to the infertility of soils and poor farming. The application of chemical fertilizers distresses soil fertility and also human health. Inappropriate use of chemical fertilizer leads to the rapid decline in production levels in most parts of the world, and hence requires the necessary standards of good cultivation practice. Biofertilizers and biopesticides have been used in recent years by farmers worldwide to preserve natural soil conditions. Biofertilizer, a replacement for chemical fertilizer, is cost-effective and prevents environmental contamination to the atmosphere, and is a source of renewable energy. In contrast to chemical fertilizers, biofertilizers are cost-effective and a source of renewable energy that preserves long-term soil fertility. The use of biofertilizers is, therefore, inevitable to increase the earth’s productivity. A low-input scheme is feasible to achieve farm sustainability through the use of biological and organic fertilizers. This study investigates the use of microbial inoculants as biofertilizers to increase crop production.

Marta Bertola, A. Ferrarini, G. Visioli

Microorganisms • 2021

Soil is one of the key elements for supporting life on Earth. It delivers multiple ecosystem services, which are provided by soil processes and functions performed by soil biodiversity. In particular, soil microbiome is one of the fundamental components in the sustainment of plant biomass production and plant health. Both targeted and untargeted management of soil microbial communities appear to be promising in the sustainable improvement of food crop yield, its nutritional quality and safety. –Omics approaches, which allow the assessment of microbial phylogenetic diversity and functional information, have increasingly been used in recent years to study changes in soil microbial diversity caused by agronomic practices and environmental factors. The application of these high-throughput technologies to the study of soil microbial diversity, plant health and the quality of derived raw materials will help strengthen the link between soil well-being, food quality, food safety and human health.

Xinpei Wei, Benkang Xie, Chu Wan et al.

Agronomy • 2024

Soil microorganisms play a crucial role in maintaining the structure and function of soil ecosystems. This study aims to explore the effects of microbial fertilizers on improving soil physicochemical properties and promoting plant growth. The results show that the application of microbial fertilizers significantly increases the richness of soil microorganisms, maintains soil microecological balance, and effectively improves the soil environment. Through various secondary metabolites, proteins, and mucilage secreted by the developing plant root system, microbial fertilizers recruit specific fungal microorganisms. These microorganisms, by binding soil particles with their extracellular polysaccharides and entwining them, fix the soil, enhance the stability of soil aggregates, and ameliorate soil compaction. Moreover, after the application of microbial fertilizers, the enriched soil microbial community not only promotes the plant’s absorption and utilization of key elements such as nitrogen (N), phosphorus (P), and potassium (K), thereby increasing fruit yield and quality, but also competes with pathogens and induces systemic resistance in plants, effectively warding off pathogenic invasions. This study highlights the potential and importance of microbial fertilizers in promoting sustainable agricultural development, offering new strategies and perspectives for future agricultural production.

Mona Parizadeh, Benjamin Mimee, Steven W. Kembel

• 0

<jats:title>ABSTRACT</jats:title><jats:p>Neonicotinoids, a class of systemic insecticides, have been widely used for decades against various insect pests. Past studies have reported non-target effects of neonicotinoids on some beneficial macro- and micro-organisms. Given the crucial role that the soil microbiota plays in sustaining soil fertility, it is critical to understand how microbial taxonomic composition and gene expression respond to neonicotinoid exposure. To date, few studies have focused on this question, and these studies have evaluated the shifts in soil microbial taxonomic composition or used soil biochemical analyses to assess the changes in microbial functions. In this study, we have applied a metatranscriptomic approach to quantify the variability in soil microbial gene expression in a two-year soybean/corn crop rotation in Quebec, Canada. We identified weak and temporally inconsistent effects of neonicotinoid application on soil microbial gene expression, as well as a strong temporal variation in soil microbial gene expression among months and years. Neonicotinoid seed treatment altered the expression of a small number of microbial genes, including genes associated with heat shock proteins, regulatory functions, metabolic processes and DNA repair. These changes in gene expression varied during the growing season and between years. Overall, the composition of soil microbial expressed genes seems to be more resilient and less affected by neonicotinoid application than soil microbial taxonomic composition. Our study is among the first to document the effects of neonicotinoid seed treatment on microbial gene expression and highlights the strong temporal variability of soil microbial gene expression and its responses to neonicotinoid seed treatments.</jats:p><jats:sec><jats:title>IMPORTANCE</jats:title><jats:p>This work provides the first example of the impacts of neonicotinoid seed treatment on community-wide soil microbial gene expression in an experimental design representing real farming conditions. Neonicotinoid pesticides have attracted a great deal of attention in recent years due to their potential non-target impacts on ecological communities and their functions. Our paper represents the first use of metatranscriptomic sequencing to offer real-time and in-depth insights into the non-target effects of this pesticide on soil microbial gene expression and on potentially beneficial soil microorganisms.</jats:p></jats:sec>

E. A. STOCKDALE, P. C. BROOKES

The Journal of Agricultural Science • 2006

<jats:p>Studies of single soil organisms, while useful in specialized cases, e.g. Rhizobia and mycohrrizae, do not yield information on the functioning of the soil ecosystem. This is because most important soil processes, e.g. carbon and nitrogen mineralization, depend upon interactions between entire suites of organisms, many of which still await identification and most of which remain unculturable.</jats:p><jats:p>For many purposes, treating the soil microbial community as a single, undifferentiated unit, the soil microbial biomass (defined as all soil organisms &lt;5000 μm<jats:sup>3</jats:sup> volume), has much to commend it. It is analogous to studying the forest rather than an individual tree and uniquely permits an understanding of the soil–plant–microbe system as a whole, rather than studying only a small part. The present paper reviews the development of methods to measure microbial dynamics over the last century, the evolution of biomass methodologies and how they have helped the study of crucial soil processes such as nutrient and carbon cycling. Possible future directions for this research are also discussed and an explanation set forth of why the manipulation of this huge population (easily comprising 10 tonnes per hectare of living microbial cells in UK arable soils) has, so far, proved elusive.</jats:p>

Janani Hariharan, Aditi Sengupta, Parwinder Grewal et al.

Agricultural &amp; Environmental Letters • 2017

<jats:sec><jats:title>Core Ideas</jats:title><jats:p><jats:list list-type="bullet"> <jats:list-item><jats:p>Microbial function is important but difficult to assess in soil.</jats:p></jats:list-item> <jats:list-item><jats:p>An omics‐driven tool, PICRUSt, was used to characterize functions of soil microbial communities.</jats:p></jats:list-item> <jats:list-item><jats:p>No‐tillage compared with plow tillage was functionally enriched for most nutrient cycles.</jats:p></jats:list-item> <jats:list-item><jats:p>Many other functions integral to soil health can be explored by the PICRUSt omics approach.</jats:p></jats:list-item> </jats:list></jats:p></jats:sec><jats:sec><jats:label/><jats:p>Soil microbial communities affect the soil's biological, chemical, and physical properties, but there is still a knowledge gap regarding the long‐term impact of tillage practices on soil microbial dynamics. Additionally, the accurate identification of belowground microbial functions is a topic of active interest. In this study, microbial community profiles and functions in soil from a 50‐plus‐year‐old experiment in Ohio, representing one of the world's longest running comparisons of a plow‐tillage system and a continuous no‐tillage system, were compared. The Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) algorithm was used to predict associated functional traits from 16S rRNA gene sequences. Analysis of the sequences revealed a large number of unidentified operational taxonomic units (67%), which is consistent with expectations of the soil ecosystem. Next, we investigated gene and enzyme predictions for nitrogen, sulfur, and methane metabolism and hydrocarbon degradation in soil. Results indicated that no‐tillage was functionally enriched for most nutrient cycles. This study has allowed us to predict distinct functional profiles as a result of legacy land uses. It serves as an example of improved analysis of the functional differences in soil managed by long‐term tillage versus no‐till.</jats:p></jats:sec>

Ene DU

Agricultural Research &amp; Technology: Open Access Journal • 0

<jats:p>A pot experiment was conducted in the screen house of the Teaching and Research Farm of Rivers State University (RSU)from March to July, 2018 to determine the effects of Effective Microorganisms Activated Solution (EMAS) and organic materials (poultry manure (PM) and dry grasses (DG)) on microbial population and activities. The six treatments made up of 2 levels of EMAS and 3 levels of organic materials were replicated three times and arranged in a Completely Randomized Design (CRD). The treated soils were incubated for 4 weeks and samples collected for microbial count and carbon dioxide evolution. Microbial activities were monitored weekly for 4 weeks. The results show a significant difference (p&lt;0.05) between soil+ effective microorganisms activated solution (SO+EMAS), soil + poultry manure + effective microorganism activated solution(S+PM+EMAS), soil + dry grasses + effective microorganism activated solution (S+DG+EMAS), soil + poultry manure (S+PM), soil + dry grasses (S+DG) and the control soil only (SO). The population of heterotrophic bacterial were significantly different, S+EMAS had the highest (9.82x109CFU/g) and the control (SO) had the least population (1.38x109CFU/g) before planting, SO had the highest population count (4.63x108 CFU/g) and S+DG had the least population count of bacteria (4.10x107CFU/g) after harvest, also a significant different exist among the treatments on CO2 evolution, S+PM had the highest mean value (0.06mg), S+EMAS had the least value (0.002mg). The results show that soils amended with EMAS improved bacterial count, lowers CO2 evolution, soils amended with PM improved CO2 evolution. Hence recommending that EMAS and organic matter (especially PM) should be used for the improvement of soil microbial population to enhance nutrient availabilities for plants and to create a sustainable agriculture.</jats:p>

, Dan Funck Jensen, Mukesh Dubey et al.

Burleigh Dodds Series in Agricultural Science • 2021

<jats:p>The fungus Clonostachys rosea was recognized as an aggressive parasite on other fungi already in the late 1950s. Research into its potential use in biological control of plant diseases soon followed. Today, there are several commercial products based on C. rosea available for biocontrol applications worldwide. Although its mycoparasitic ability has attracted a lot of interest, C. rosea is now viewed as an ecological generalist whose lifestyle also includes plant endophytism, rhizosphere competence and polyphagous ability. Protocols for producing high amounts of C. rosea spores are available for both solid state and liquid fermentation. Low temperature and low moisture content are key factors that influence the shelf life of C. rosea propagules. Products based on C. rosea can be delivered to flowers using bumble bees, applied by spraying or as seed dressing or by incorporation into the soil. Clonostachys rosea is today an established factor in sustainable plant protection strategies.</jats:p>

SHAON MUKHERJEE, JAMAL SIDDIQUI, JUHI SAXENA

The Indian Journal of Agricultural Sciences • 0

<jats:p>The increased use of chemical fertilizers, pesticides, soil-based heavy metals to improve productivity in agriculture results into higher pollution level in agroecosystem. It has become a major issue on a global scale that seriously jeopardizes people’s health and welfare as well as affects society and overall economy. In view of this, there is an urgent need to detect pollutants in the agroecosystem so that remediation practices can be implemented in time. The evolution of more responsive, affordable and precise technology is needed to create nano-sensors or nanodevices that can be used to monitor agricultural pollution, and the processes involved in pollution control. Major focused ones are those that can detect pollutants at very low concentration levels, as well as point-to-point sensing, in situ, and uninterrupted monitoring devices that offer synchronized data. These sensors are readily available in the market for the detection of organic pollutants, gases, volatile organic molecules, heavy metal ions, hazardous metal ions, etc. but they consume a lot of power and lack sophisticated technologies for improved selectivity and sensitivity. Their precision, sensitivity, response speed and environmental stability under actual operating conditions can all be improved with the aid of nanotechnology. In this study an attempt was made to describe how microbial biosensors can be used to detect toxic materials in agroecosystems. Additionally, an application of nanomaterials as pesticides and antimicrobial agent has also been discussed.</jats:p>

Gabriele Bellotti, Claudia Cortimiglia, Maria Elena Antinori et al.

Microbial Genomics • 2025

<jats:p>Microbial biostimulants (MBs) offer a sustainable approach to agriculture by helping to reduce reliance on synthetic fertilizers. However, as MBs are intentionally released into the environment, their safety should be rigorously assessed. While taxa with qualified presumption of safety (QPS) benefit from established safety indications, non-QPS taxa lack such guidance. To address this gap, we propose a pipeline combining whole genome sequencing (WGS) and extensive literature search (ELS) data to evaluate microbial safety. We analysed public genomes of three QPS species (<jats:italic>Rhodopseudomonas palustris</jats:italic>, <jats:italic>Bacillus velezensis</jats:italic>, <jats:italic>Priestia megaterium</jats:italic>) and four non-QPS genera (<jats:italic>Arthrobacter</jats:italic>, <jats:italic>Azotobacter</jats:italic>, <jats:italic>Azospirillum</jats:italic>, <jats:italic>Herbaspirillum</jats:italic>), screening them for virulence factors (VFs), antimicrobial resistance (AMR) genes and mobile genetic elements (MGEs). Results confirmed the safety of QPS taxa, revealing no VFs and only a few intrinsic and non-clinically relevant AMRs. Among non-QPS taxa, VF hits were more prevalent in <jats:italic>Azotobacter</jats:italic> and <jats:italic>Azospirillum</jats:italic> spp., though they were mostly related to beneficial plant interactions rather than pathogenicity. AMR genes in non-QPS taxa were primarily associated with efflux pumps or were sporadically distributed. Notably, the only genus-wide pattern observed was that most <jats:italic>Azospirillum</jats:italic> and <jats:italic>Herbaspirillum</jats:italic> genomes harboured chromosomally encoded <jats:italic>β</jats:italic>-lactamases sharing similar genetic structures; however, the detected <jats:italic>β</jats:italic>-lactamase (<jats:italic>bla</jats:italic>) genes were distantly related to clinically relevant <jats:italic>bla</jats:italic> variants, and the absence of MGEs suggests a low risk of horizontal gene transfer, indicating the overall safety of these genera. In general, this WGS–ELS framework provides a robust tool for assessing the safety of non-QPS MBs, supporting regulatory decision-making and ensuring their safe use in sustainable agriculture while safeguarding public health.</jats:p>

Yicheng Wu, Guanghua He, Shuiliang Chen et al.

Water Environment Research • 2020

<jats:title>Abstract</jats:title><jats:sec><jats:label/><jats:p>To achieve deep understandings on the effects of structure and surface properties of anode material on the performance of bioelectrochemical systems, the present research investigated the bacterial community structures of biofilms attached to different three‐dimensional anodes including carbon felt and materials derived from pomelo peel, kenaf stem, and cardboard with 454 pyrosequencing analysis based on the bacterial 16S rRNA gene. The results showed that bacterial community structures, especially the relative abundance of exoelectrogens, were significantly related to the types of adopted three‐dimensional anode materials. Proteobacteria was the shared predominant phylum, accounting for 55.4%, 52.1%, 66.7%, and 56.1% for carbon felt, cardboard, pomelo peel, and kenaf stem carbon, respectively. The most abundant OTU was phylogenetically related to the well‐known exoelectrogen of <jats:italic>Geobacter</jats:italic>, with a relative abundance of 16.3%, 19.0%, 36.3%, and 28.6% in carbon felt, cardboard, pomelo peel, and kenaf stem, respectively. Moreover, another exoelectrogen of <jats:italic>Pseudomonas</jats:italic> sp. accounted for 4.9% in kenaf stem and 3.9% in carbonboard, respectively. The results implied the macrostructure and properties of different anode materials might result in different niches such as hydrodynamics and substrate transport dynamics, leading to different bacterial structure, especially different relative abundance of exoelectrogens, which consequently affected the performance of bioelectrochemical systems.</jats:p></jats:sec><jats:sec><jats:title>Practitioner points</jats:title><jats:p> <jats:list list-type="bullet"> <jats:list-item><jats:p>Bioelectrochemical systems (BESs) represent a novel biotechnology platform to simultaneously treat wastewaters and produce electrical power.</jats:p></jats:list-item> <jats:list-item><jats:p>Three‐dimensional materials derived from nature plant as anode to promote electricity output from BESs and reduce the construct cost of BESs.</jats:p></jats:list-item> <jats:list-item><jats:p>Macrostructure of the three‐dimensional anode material affected phylotype richness and phylogenetic diversity of microorganisms in anodic biofilm of BESs.</jats:p></jats:list-item> <jats:list-item><jats:p><jats:italic>Geobacter</jats:italic> as well‐known exoelectrogen was the most abundant in biofilm attached to three‐dimensional anode.</jats:p></jats:list-item> </jats:list> </jats:p></jats:sec>

Kyungmin Kim, Suyeon Lee, Y. Choi et al.

International Journal of Environmental Research and Public Health • 2022

Currently, little is known about the occurrences of fungi-derived microbial volatile organic compounds (mVOCs) in various indoor materials and their detection in residential environments, despite mVOCs being linked to several acute health effects. We identified various mVOCs emitted from fungi grown on PVC wallpaper, silicone rubber, and malt extract agar. We also investigated mVOCs temporal emission and whether fungi-derived VOCs concentration can be used to estimate fungal concentration in the air using active and passive air sampling methods. Among the three fungal growth media included in this study, silicone rubber produced the most variety of mVOCs: 106 compounds (from Aspergillus niger), 35 compounds (from Alternaria alternata), and 85 compounds (from Penicillium chrysogenum). We also found the emission patterns of eight chemical classes (i.e., aromatics, ethers, aliphatics, alcohols, ketones, aldehydes, chlorides, and nitrides) from the three different fungi. From the results of our field experiments in 11 residential environments, passive air samplers led to higher correlations coefficients (0.08 to 0.86) between mVOCs’ air concentrations and airborne fungal concentrations, compared with active air samplers, which showed negative correlation coefficients (−0.99 to −0.02) for most compounds. This study elucidated the occurrence and temporal emission patterns of fungal VOCs in residential environments.

M. Szczotko, Izabela Orych, Łukasz Mąka et al.

Atmosphere • 2022

Aims: With the ongoing pandemic and increased interest in measures to improve indoor air quality, various indoor air purifiers have become very popular and are widely used. This review presents the advantages and disadvantages of various types of technologies used in air purifiers in terms of reducing microbial contamination. Methods: A literature search was performed using Web of Science, Scopus, and PubMed, as well as technical organizations dealing with indoor air-quality to identify research articles and documents within our defined scope of interest. Relevant sections: The available literature data focus mainly on the efficiency of devices based on tests conducted in laboratory conditions with test chambers, which does not reflect the real dimensions and conditions observed in residential areas. According to a wide range of articles on the topic, the actual effectiveness of air purifiers is significantly lower in real conditions than the values declared by the manufacturers in their marketing materials as well as technical specifications. Conclusions: According to current findings, using indoor air purifiers should not be the only measure to improve indoor air-quality; however, these can play a supporting role if their application is preceded by an appropriate technical and environmental analysis considering the real conditions of its use.

Michelle M. McKnight, J. Neufeld

Applied and Environmental Microbiology • 2024

ABSTRACT Nitrification by aquarium biofilters transforms ammonia waste (NH3/NH4+) to less toxic nitrate (NO3-) via nitrite (NO2-). Prior to the discovery of complete ammonia-oxidizing (“comammox” or CMX) Nitrospira, previous research revealed that ammonia-oxidizing archaea (AOA) dominated over ammonia-oxidizing bacteria (AOB) in freshwater aquarium biofilters. Here, we profiled aquarium biofilter microbial communities and quantified the abundance of all three known ammonia oxidizers using 16S rRNA gene sequencing and quantitative PCR (qPCR), respectively. Biofilter and water samples were each collected from representative residential and commercial freshwater and saltwater aquaria. Distinct biofilter microbial communities were associated with freshwater and saltwater biofilters. Comammox Nitrospira amoA genes were detected in all 38 freshwater biofilter samples (average CMX amoA genes: 2.2 × 103 ± 1.5 × 103 copies/ng) and dominant in 30, whereas AOA were present in 35 freshwater biofilter samples (average AOA amoA genes: 1.1 × 103 ± 2.7 × 103 copies/ng) and only dominant in 7 of them. The AOB were at relatively low abundance within biofilters (average of 3.2 × 101 ± 1.1 × 102 copies of AOB amoA genes/ng of DNA), except for the aquarium with the highest ammonia concentration. For saltwater biofilters, AOA or AOB were differentially abundant, with no comammox Nitrospira detected. Additional sequencing of Nitrospira amoA genes revealed differential distributions, suggesting niche adaptation based on water chemistry (e.g., ammonia, carbonate hardness, and alkalinity). Network analysis of freshwater microbial communities demonstrated positive correlations between nitrifiers and heterotrophs, suggesting metabolic and ecological interactions within biofilters. These results demonstrate that comammox Nitrospira plays a previously overlooked, but important role in home aquarium biofilter nitrification. IMPORTANCE Nitrification is a crucial process that converts toxic ammonia waste into less harmful nitrate that occurs in aquarium biofilters. Prior research found that ammonia-oxidizing archaea (AOA) were dominant over ammonia-oxidizing bacteria (AOB) in freshwater aquarium biofilters. Our study profiled microbial communities of aquarium biofilters and quantified the abundance of all currently known groups of aerobic ammonia oxidizers. The findings reveal that complete ammonia-oxidizing (comammox) Nitrospira were present in all freshwater aquarium biofilter samples in high abundance, challenging our previous understanding of aquarium nitrification. We also highlight niche adaptation of ammonia oxidizers based on salinity. The network analysis of freshwater biofilter microbial communities revealed significant positive correlations among nitrifiers and other community members, suggesting intricate interactions within biofilter communities. Overall, this study expands our understanding of nitrification in aquarium biofilters, emphasizes the role of comammox Nitrospira, and highlights the value of aquaria as microcosms for studying nitrifier ecology. Nitrification is a crucial process that converts toxic ammonia waste into less harmful nitrate that occurs in aquarium biofilters. Prior research found that ammonia-oxidizing archaea (AOA) were dominant over ammonia-oxidizing bacteria (AOB) in freshwater aquarium biofilters. Our study profiled microbial communities of aquarium biofilters and quantified the abundance of all currently known groups of aerobic ammonia oxidizers. The findings reveal that complete ammonia-oxidizing (comammox) Nitrospira were present in all freshwater aquarium biofilter samples in high abundance, challenging our previous understanding of aquarium nitrification. We also highlight niche adaptation of ammonia oxidizers based on salinity. The network analysis of freshwater biofilter microbial communities revealed significant positive correlations among nitrifiers and other community members, suggesting intricate interactions within biofilter communities. Overall, this study expands our understanding of nitrification in aquarium biofilters, emphasizes the role of comammox Nitrospira, and highlights the value of aquaria as microcosms for studying nitrifier ecology.

James Naphtali, Alexander W. Y. Chan, F. Saleem et al.

Processes • 2022

On-site wastewater treatment systems (OWTS) are primarily monitored using physiochemical factors, including chemical oxygen demand (COD) and residual total suspended solids (TSS), which are indirect measures of the microbial action during the anaerobic digestion process. Changes in anaerobic digester microbial communities can alter the digester performance, but this information cannot be directly obtained from traditional physicochemical indicators. The potential of metagenomic DNA sequencing as a tool for taxonomic and functional profiling of microbial communities was examined in both common conventional and plug flow-type anaerobic digesters (single-pass and recirculating). Compared to conventional digesters, plug flow-type digesters had higher relative levels of sulfate-reducing bacteria (Desulfovibrio spp.) and hydrogenotrophic methanogens (Methanospirillum spp.). In contrast, recirculating anaerobic digesters were enriched with denitrifier bacteria and hydrogenotrophic methanogens, and both were significantly correlated with physicochemical factors such as COD and TSS. Stratification of microbial communities was observed along the digester treatment process according to hydrolytic, acidogenic, acetogenic, and methanogenic subgroups. These results indicate that the high-throughput DNA sequencing may be useful as a monitoring tool to characterize the changes in bacterial communities and the functional profile due to differences in digester design in on-site systems.

James D. Johnston, Ashlin E Cowger, K. S. Weber

Indoor Air • 2022

Abstract Evaporative cooling is an energy efficient form of air conditioning in dry climates that functions by pulling hot, dry outdoor air across a wet evaporative pad. While evaporative coolers can help save energy, they also have the potential to influence human health. Studies have shown residential evaporative coolers may pull outdoor air pollutants into the home or contribute to elevated levels of indoor bioaerosols that may be harmful to health. There is also evidence that evaporative coolers can enable a diverse microbial environment that may confer early‐life immunological protection against the development of allergies and asthma or exacerbate these same hypersensitivities. This review summarizes the current knowledge of bioaerosol and microbiological studies associated with evaporative coolers, focusing on harmful and potentially helpful outcomes from their use. We evaluate the effects of evaporative coolers on indoor bacterial endotoxins, fungal β‐(1 → 3)‐D‐glucans, dust mite antigens, residential microbial communities, and Legionella pneumophila. To our knowledge, this is the first review to summarize and evaluate studies on the influence that evaporative coolers have on the bioaerosol and microbiological profile of homes. This brings to light a gap in the literature on evaporative coolers, which is the lack of data on health effects associated with their use.

J. Weidhaas, M. Olsen, J. McLean et al.

Journal of Water Reuse and Desalination • 2022

Arid and semi-arid locations are increasingly utilizing nontraditional irrigation water including reclaimed wastewater. Human health risk associated with reclaimed wastewater use was determined by testing reservoir, distribution line and home spigot water (n=190) and 14 types of vegetables and fruits (n=90) harvested from 5 home gardens for 7 waterborne pathogens, 47 antibiotic resistance genes and 12 pharmaceuticals and personal care products (PPCPs). Based on surveys of the residents’ use of the reclaimed wastewater, two exposure routes were modeled: irrigation of fruits and vegetables and drinking from irrigation hoses. Probabilistic quantitative microbial risk assessment indicated that consumption of raw vegetables and fruits exceeded a 0.015 benchmark illness rate due to adenovirus and enterococci. Chemical risk assessments indicated that consumption of tons of vegetables per day and hundreds to millions of gallons of water per day would be needed to reach an unacceptable risk among the 10 PPCPs detected in home spigot water, indicating de minimis risk from PPCPs. Eight different drug resistance gene families were detected in the water samples and crops indicating that antibiotic-resistant organisms are present on foods irrigated with reclaimed water containing pharmaceuticals. These results elucidate the combined risk from pathogens and PPCPs from reclaimed wastewater irrigation.

R. Arbianti, T. S. Utami, Vifki Leondo et al.

IOP Conference Series: Materials Science and Engineering • 2018

Microbial Fuel Cell (MFC) provides a new alternative in the treatment of organic waste. MFC produces 50-90% less sludge to be disposed than other methods. MFC technology can utilize existing microorganisms in the waste as a catalyst to generate electricity and simultaneously also serves as a wastewater treatment unit itself. Tempeh wastewater is one of the abundant industrial wastewater which can be processed using MFC. Research using the selective mixed culture is very likely to do due to the good result on COD removals by adding mixed culture. Microorganisms in tempeh wastewater consist of bacteria gram positive and gram negative. This study focused on the aspects of waste treatment which is determined by decreased levels of COD and BOD. Variations in this study are the formation time of biofilm and the addition of selective gram. MFC operated for 50 hours. For a variation of biofilm formation, experiments were performed after incubation by replacing incubation substrates used in the formation of biofilms. Biofilm formation time in this study was 3 days, 5 days, 7 days and 14 days. Gram positive and gram negative bacteria were used in selective mixed culture experiments. Selective mixed culture added to the reactor by 1 mL and 5 mL. Selection of gram-positive or gram-negative bacteria carried by growing mixed culture on selective media. COD and BOD levels were measured in the wastewater before and after the experiment conducted in each variation. Biofilm formation optimum time is 7 days which decrease COD and BOD levels by 18.2% and 35.9%. The addition of gram negative bacteria decreases COD and BOD levels by 29.32% and 51.32%. Further research is needed in order to get a better result on decreasing levels of COD and BOD.

D. Pant, G. V. Bogaert, Y. Alvarez-Gallego et al.

Environmental Engineering and Management Journal • 2016

Microbial Fuel Cells (MFCs), the bioelectrochemical devices for conversion of waste into electricity through bacterial metabolic activity can use substrates with different complexity and strength. Wastewaters with moderate to high organic content can be exploited as MFC substrates. In this study, four different industrial wastewaters (from a chemical company, milk industry, soyabased food and soft-drink company and laundry) with different compositions were used as substrates in identical MFCs. In the design of MFC, carbon cloth was used as anode and low-cost carbon based, non-platinized electrode as air cathode. Anode and cathode were separated by an ion permeable membrane Zirfon , directly attached on the cathode. After initial operation with 10 mM acetate as substrate, the cells were switched to real industrial wastewaters without pre-treatment. When operational, an electrochemically active biofilm and anode open circuit voltage (OCV) of -500 mV vs. Ag/AgCl. OCV was obtained which recovered after dropping in all cells, showing the ability of anodic bacteria to utilize industrial wastewaters as substrate. A maximum power of 419 mW m-2 was obtained with milk industry wastewater, while the electrodes in MFC with chemical industry wastewater were corroded after few days of operation suggesting that every wastewater is not suitable as substrate for electricity production and treatment in MFCs.

Natchapon Srinak, Porntip Chiewchankaset, S. Kalapanulak et al.

PLOS Computational Biology • 2024

The efficiency of microbial fuel cells (MFCs) in industrial wastewater treatment is profoundly influenced by the microbial community, which can be disrupted by variable industrial operations. Although microbial guilds linked to MFC performance under specific conditions have been identified, comprehensive knowledge of the convergent community structure and pathways of adaptation is lacking. Here, we developed a microbe-microbe interaction genome-scale metabolic model (mmGEM) based on metabolic cross-feeding to study the adaptation of microbial communities in MFCs treating sulfide-containing wastewater from a canned-pineapple factory. The metabolic model encompassed three major microbial guilds: sulfate-reducing bacteria (SRB), methanogens (MET), and sulfide-oxidizing bacteria (SOB). Our findings revealed a shift from an SOB-dominant to MET-dominant community as organic loading rates (OLRs) increased, along with a decline in MFC performance. The mmGEM accurately predicted microbial relative abundance at low OLRs (L-OLRs) and adaptation to high OLRs (H-OLRs). The simulations revealed constraints on SOB growth under H-OLRs due to reduced sulfate-sulfide (S) cycling and acetate cross-feeding with SRB. More cross-fed metabolites from SRB were diverted to MET, facilitating their competitive dominance. Assessing cross-feeding dynamics under varying OLRs enabled the execution of practical scenario-based simulations to explore the potential impact of elevated acidity levels on SOB growth and MFC performance. This work highlights the role of metabolic cross-feeding in shaping microbial community structure in response to high OLRs. The insights gained will inform the development of effective strategies for implementing MFC technology in real-world industrial environments.

Shuai Zhao, Pu Liu, Yongyan Niu et al.

Sensors • 2018

Hexavalent chromium (Cr(VI)) is a well-known toxic heavy metal in industrial wastewater, but in situ and real time monitoring cannot be achieved by current methods used during industrial wastewater treatment processes. In this study, a Sediment Microbial Fuel Cell (SMFC) was used as a biosensor for in situ real-time monitoring of Cr(VI), which was the organic substrate is oxidized in the anode and Cr(VI) is reduced at the cathode simultaneously. The pH 6.4 and temperature 25 °C were optimal conditions for the operation. Under the optimal conditions, linearity (R2 = 0.9935) of the generated voltage was observed in the Cr(VI) concentration range from 0.2 to 0.7 mg/L. The system showed high specificity for Cr(VI), as other co-existing ions such as Cu2+, Zn2+, and Pb2+ did not interfere with Cr(VI) detection. In addition, when the sediment MFC-based biosensor was applied for measuring Cr(VI) in actual wastewater samples, a low deviation (<8%) was obtained, which indicated its potential as a reliable biosensor device. MiSeq sequencing results showed that electrochemically active bacteria (Geobacter and Pseudomonas) were enriched at least two-fold on the biofilm of the anode in the biosensor as compared to the SMFC without Cr(VI). Cyclic voltammetry curves indicated that a pair of oxidation/reduction peaks appeared at −111 mV and 581 mV, respectively. These results demonstrated that the proposed sediment microbial fuel cell-based biosensor can be applied as an early warning device for real time in situ detection of Cr(VI) in industrial wastewaters.

I. W. Suryawan, I. Septiariva, Ariyanti Sarwono

• 2020

The purpose of this review is to provide current information regarding industrial wastewater treatment with MFC technology with the addition of biocatalysts and pretreatments. Moreover, this review also updates industrial waste treatment technology with MFC technology in Indonesia. Waste could be generated from domestic activities as well as non-domestic activities, such as industries. Industries produce waste with quite high organic content. This organic material is not easily degraded in biological treatment. Wastewater treatment, currently, aims only to meet standards quality and not to reuse. In Indonesia, the reuse processes, one of which is still rarely found in the form of energy. Industries that can process and convert wastewater energy can help the government realize sustainable development in the energy sector. One of the technologies is the Microbial Fuel Cell (MFC). Previous MFC research that had been carried out was limited to laboratory scale with a volume of less than 1 L and, among them, used mixed or artificial waste. MFC processing uses anode in wastewater as a substrate source and generates electrons under anaerobic conditions. Electron formation could be accelerated by adding biocatalysts such as enzymes and specific microorganisms. The processing occurred in an anaerobic anode that could be increased by increasing the substrate's biodegradability value in the waste. The biodegradability value can be increased by pretreatment with ozone or ultrasonic technology. In Indonesia, research on industrial wastewater treatment with MFC as well as biocatalyst and pretreatment is still relatively minimal.

A. Pugazhendi, Afnan Eid Al‐Mutairi, M. Jamal et al.

International Journal of Energy Research • 2020

The present study investigated seafood industrial wastewater treatment with corresponding power generation in air cathode microbial fuel cell under saline condition (40 g/L). The results recorded total chemical oxygen demand) removal of 52 ± 1.8%, 64 ± 1.1%, 85 ± 1.2%, 89 ± 1.4%, and 76 ± 1.2% to the corresponding organic load (OL) of 0.5, 0.75, 1, 1.25, and 1.5 gCOD/L under saline condition. Soluble chemical oxygen demand reduction was in the range of 46% to 78% at OL of 0.5 to 1.5 gCOD/L. The maximum power density (530 ± 15 mW/m2) and coulombic efficiency (52 ± 2.4%) was procured at the OL of 1.25 and 0.5 gCOD/L, respectively. Total suspended solids removal was 74 ± 1.5% at OL of 1.25 gCOD/L and 64 ± 1.3% at OL 1.5 gCOD/L. Bacterial community analysis for anode region samples for OL 0.5 and 1 gCOD/L was extensively dominated by Bacillus (MN880233) with 75.8% and 55.8%, respectively. Interestingly at 1.25 gCOD/L OL, Rhodococcus (MN880237) was predominant (42.3%) strain in the anode region and recorded high power production under saline condition. Sludge samples subjected to phylogenetic analysis explored the dominance of Clostridium, Turicibacter, and Marinobacter at different OL from 0.5 to 1.5 gCOD/L. Bacterial community results at 1.25 gCOD/L of OL sludge samples revealed completely different strains of dominancy in the community. Marinobacter (53.3%), Ochrobactrum (19.3%), and Bacillus (8.1%). Thus, the phylogenetic analysis of the anodic and sludge samples clearly detailed the presence of halophilic bacterial strains with high potential to treat seafood processing industrial wastewater and excellent exoelectrogenic activity for power production.

Sumaya Sarmin, Asmida Ideris, Sim Yee Chin et al.

Journal of Chemical Engineering and Industrial Biotechnology • 0

<jats:p>This paper presents the performance of air-cathode microbial fuel cell (AC-MFC) treating the petrochemical wastewater (PCW) from acrylic acid plant. The wastewater which is typically incinerated and possesses very high chemical oxygen demand (COD) due to presence of acrylic acid along with other organic acids. The goal of the present study is to evaluate the viability of treating the wastewater using yeast (Saccharomyces cerevisiae) as biocatalyst in AC-MFC for simultaneous treatment of wastewater and electricity generation. This study demonstrates that Saccharomyces  cerevisiae could function as a good biocatalyst producing high power density of 0.24 W/m3 using PCW with an initial COD of 26,000 mg/L. The COD removal efficiency and the columbic efficiency (CE) were found as 38% and 23.6% respectively. The electron transfer process across the  electrode/biofilm/solution interface was analyzed by electrochemical impedance spectroscopy (EIS). The present work demonstrates the potential of MFC for the treatment of acrylic acid plant PCW using Saccharomyces cerevisiae as biocatalyst.</jats:p>

ST Swift

Distillate Fuel: Contamination, Storage, and Handling • 1988

<jats:p>The primary goal of a fuel handling system is the delivery of clean and dry fuel to the customer. Microbial growth has been implicated in a number of problems such as tank corrosion, filter plugging, and deactivation of filter/coalescers. Therefore, the identification and elimination of microbial growth in fuel handling systems is very important. This paper discusses, through the use of two examples, the identification of microbial growth in samples from fuel handling systems. A simple flow chart system for isolating and characterizing the particular microbial contaminants, bacteria, fungus, and sulfate reducing bacteria, is presented. The characterization of sediments by solvent separation is also discussed. Finally, the current techniques for prevention of microbial growth in fuel handling systems are discussed. The results of a field test of a water-bottoms biocide treatment of a fuel storage tank are presented.</jats:p>

Jing Cai, Ping Zheng, Mahmood Qaisar et al.

Journal of Industrial Microbiology and Biotechnology • 2014

<jats:title>Abstract</jats:title> <jats:p>The effect of operating modes on the simultaneous sulfide and nitrate removal were studied in two-chamber microbial fuel cells (MFCs). The batch and continuous operating modes were compared and evaluated in terms of substrate removal and electricity generation. Upon gradual increase in the influent sulfide concentration from 60 to 1,020 S mg L−1, and the hydraulic retention time decrease from 17.2 to 6 h, the MFC accomplished a good substrate removal efficiency whereby nitrogen and sulfate were the main end products. The removal efficiency of the MFC in the continuous mode was much higher than that in the batch mode, and its current densities in the continuous mode were more stable and higher than in the batch mode, which could be explained by the linear relationship between electrons released by the substrates and accepted on the electrodes. The electricity output in the continuous mode of the MFC was higher than that in the batch mode. MFC's operation in the continuous mode was a better strategy for the simultaneous treatment of sulfide and nitrate.</jats:p>

François-Joseph Daniel

Science, Technology, &amp; Human Values • 2023

<jats:p> Biological waste recycling has recently attracted widespread interest and investment. Large industrial plants that use microbiological engineering to process municipal waste and produce biogas have been established in different countries including Germany, France, Portugal, Brazil, Canada, and China, to name a few. These biowaste facilities are not simply classical energy infrastructures, as they are commonly described, but rather rely on the power of bacteria, archaea, and fungi at several levels to accomplish the work of waste metamorphosis. Such an appropriation of microbes’ vital force is based on specific and complex human–microbe relations, or microbiopolitics, that rely on practices of attention, care, and proximity with waste material. However, in these industrial attempts of upgrading the metabolic work of bacteria, the need for more hands-on daily care of waste materials and biological processes is being superseded by the automation of waste processing. Close examination of the French context shows that this shift produces ignorance regarding the growth and evolution of bacterial colonies and reduces humans’ attention and proximity to the industrial process, thereby depriving the microbes of elements that hitherto kept them domesticated. </jats:p>

Jing Wang, Youhong Tang, Yuan Huang

Materials Science and Technology • 0

<jats:title>Abstract</jats:title><jats:p>Cellulose produced by some bacteria (bacterial cellulose, BC) represents an interesting emerging biocompatible nanomaterial.<jats:italic>It has been widely used in tissue engineering. BC possesses unique properties, such as high mechanical properties, high purity, excellent microstructure, high water‐holding capacity, and high crystallinity</jats:italic>. Despite the intensive research, application of BC has been limited, due to its biological activity and pore structure. This study summarized the modifications of structure and composition. Several biomaterials could be associated with BC, for example gelatin, chitosan, heparin, collagen, and hydroxyapatite, and several methods were used to control the microstructure of BC, namely, laser‐patterning technique and freeze‐drying technology. The results confirmed BC as a promising biomaterial with the potential to be an effective biopolymer in biomedical fields. These approaches will help researchers to develop new ideas in tissue engineering field.</jats:p>

Samriddh Srivastava, Garima Mathur

Current Applied Science and Technology • 0

<jats:p>Bacterial cellulose (BC) is a flexible biopolymer having valuable properties like high purity (without hemicellulose and lignin), high percentage of crystallinity, water retention, mechanical strength, biodegradability and unique biocompatibility. Unlike plant cellulose, bacterial cellulose is produced by many bacterial species. Recent advances in research have identified several producers of BC but the key producer is Komagataeibacter xylinus. BC produced from K. xylinus is known to possess captivating structural, physical, and chemical properties, hence making it a significant natural polymer to be used for future innovative research purposes. This review paper discusses the structural and physicochemical properties of BC; its natural production from bacteria as well as its production under optimized culture conditions. Since the demand for useful composites is high, the involvement of BC in the development of BC-based composites has also been discussed in detail in this paper. This review paper also highlights the diverse applications of BC in the biomedical, electronics, food, textile and pharmaceutical industries. The involvement of BC in the food and pharmaceutical industries can lead to further development of several BC-based super foods and next-generation wound dressings. On the basis of the compiled information in this review paper as well as that in the available literature, future studies should be focused on BC-based drug delivery mechanisms and their performance in in vivo and in vitro experiments; studies that should help to understand this biopolymer in a meticulous manner.</jats:p>

Mohamed M. Said, Omaima M. Ahmed

Aquaculture Nutrition • 2022

<jats:p>Biofloc technology has a high impact on enhancing shrimp production. Suitable supplemented carbohydrates (CHO) could affect the type of microorganisms developed in the system, which reflects on shrimp production, food safety, and public health. Here, we aimed to compare the effects of sugarcane molasses and wheat flour as carbohydrate sources on biofloc technology. That was achieved through measuring the following parameters: water quality, growth performance, feed utilization, floc composition, shrimp whole body composition, microbial community, and biofloc shrimp food bacterial quality. Postlarvae of whiteleg shrimp (Litopenaeus vannamei) with a mean weight (<jats:inline-formula> <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" id="M1"> <a:mn>38.47</a:mn> <a:mo>±</a:mo> <a:mn>5.8</a:mn> <a:mtext> </a:mtext> <a:mtext>mg</a:mtext> </a:math> </jats:inline-formula>) were stocked at a density of 200 individuals/m2 and cultured under a biofloc system for 128 days in six tanks with a total water volume of 30 m2 each. Water quality analysis revealed a better-dissolved oxygen concentration (5.59 mg/L) in the wheat flour treatment, whereas no significant differences were found between the two treatments in ammonia, nitrite, and pH levels. Increased turbidity (64.27 NTU) and floc volume (18.40 mL/L) were recorded with molasses treatment. Growth performance including final weight, weight gain, average daily gain, weight gain per week, and specific growth rate (12.37 g, 12.34 g, 0.096 g/d, 0.68, and 4.70%, respectively) were all significantly higher in the molasses treatment. Wheat flour treatment was associated with a higher survival rate (99%), biomass (71.16 Kg), and biomass increase percentage (395.337) in shrimps. It also improved feed utilization in terms of a lower feed conversion ratio (1.37) and higher protein efficiency ratio (1.92). The chemical composition of biofloc and shrimp whole body were both nutritious higher in wheat flour treatment. In water, total heterotrophic bacterial counts with sugarcane molasses treatment and wheat flour were estimated as <jats:inline-formula> <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" id="M2"> <c:mn>3.4</c:mn> <c:mo>×</c:mo> <c:msup> <c:mrow> <c:mn>10</c:mn> </c:mrow> <c:mrow> <c:mn>5</c:mn> </c:mrow> </c:msup> <c:mtext> </c:mtext> <c:mtext>CFU</c:mtext> <c:mo>/</c:mo> <c:mtext>mL</c:mtext> </c:math> </jats:inline-formula> and <jats:inline-formula> <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" id="M3"> <e:mn>1.2</e:mn> <e:mo>×</e:mo> <e:msup> <e:mrow> <e:mn>10</e:mn> </e:mrow> <e:mrow> <e:mn>5</e:mn> </e:mrow> </e:msup> <e:mtext> </e:mtext> <e:mtext>CFU</e:mtext> <e:mo>/</e:mo> <e:mtext>mL</e:mtext> </e:math> </jats:inline-formula>, respectively, with no significant difference. In both treatments, beneficial bacteria such as lactic acid bacteria and Enterobacter cloacae were identified in water with the absence of pathogenic Vibrio spp. Wheat flour had a significantly lower total Vibrio-like count (TVC). Shrimps had lower TVC (<jats:inline-formula> <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" id="M4"> <g:mn>1.9</g:mn> <g:mo>×</g:mo> <g:msup> <g:mrow> <g:mn>10</g:mn> </g:mrow> <g:mrow> <g:mn>4</g:mn> </g:mrow> </g:msup> <g:mtext> </g:mtext> <g:mtext>CFU</g:mtext> <g:mo>/</g:mo> <g:mtext>g</g:mtext> </g:math> </jats:inline-formula>) with flour than with molasses (<jats:inline-formula> <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" id="M5"> <i:mn>1.32</i:mn> <i:mo>×</i:mo> <i:msup> <i:mrow> <i:mn>10</i:mn> </i:mrow> <i:mrow> <i:mn>5</i:mn> </i:mrow> </i:msup> <i:mtext> </i:mtext> <i:mtext>CFU</i:mtext> <i:mo>/</i:mo> <i:mtext>g</i:mtext> </i:math> </jats:inline-formula>). Cronobacter spp. were associated with shrimps in BFT supplemented with molasses, which might pose a potential risk to food safety. In conclusion, the use of wheat flour was the best for shrimp production and shrimp food bacterial quality.</jats:p>

J. Nieman, G.M. Brion

Water Science and Technology • 2003

<jats:p>This study presents an extension of ongoing research into the utility of the ratio of colonies isolated on membrane filters during the total coliform test using m-Endo broth media. Investigations into the relative shifts in concentrations of indicator bacterial populations over time, in laboratory-based survival studies conducted with filtered river water, were undertaken. Also, analysis of Kentucky River water quality data collected from the inlet of a local water treatment plant was carried out. Survival studies found that the ratio between the raw concentrations of atypical colonies (AC) and total coliform colonies (TC) was directly related to the amount of time coliform spiked river water had been held in open jars in the laboratory. The AC/TC ratio in the jars would rise from &amp;lt;1 at the time of coliform spiking to &amp;gt;200 within 4d. The rise in AC/TC ratio with time in river water was confirmed in the analysis of two years of Kentucky River water quality data where the average AC/TC ratio during months with high river flow (rain) was 3.37 and rose to an average of 27.58 during months with low flow. The average AC/TC ratio during high flow months compared to that of raw human sewage (3.9) and the ratio increased to values associated with animal impacted urban runoff (18.9) during low flow months.</jats:p>

Azhar G. Shalaby, Neveen R. Bakry, Abeer A. E. Mohamed et al.

Veterinary World • 2020

<jats:p>Background and Aim: Flinders Technology Associates (FTA) cards simplify sample storage, transport, and extraction by reducing cost and time for diagnosis. This study evaluated the FTA suitability for safe transport and storage of Gram-positive and Gram-negative bacterial cells of animal origin on its liquid culture form and from organ impression smears (tissues) under the same routine condition of microbiological laboratory along with detecting their nucleic acid over different storage conditions. Materials and Methods: Increase in bacterial count from 104 to 107 (colony-forming units/mL) of 78 isolates representing seven bacterial species was applied onto cards. FTA cards were grouped and inoculated by these bacteria and then stored at different conditions of 24-27°C, 4°C, and –20°C for 24 h, for 2 weeks, for 1 and 3 month storage, respectively. Bacteriological examination was done, after which bacterial DNA was identified using specific primers for each bacterial type and detected by polymerase chain reaction (PCR). Results: The total percentage of recovered bacteria from FTA cards was 66.7% at 24-27–C for 24 h, the detection limit was 100% in Gram-positive species, while it was 57.4% in Gram-negative ones. Regarding viable cell detection from organ impression smears, it was successful under the previous conditions. No live bacterial cells were observed by bacteriological isolation rather than only at 24-27°C for 24 h storage. All bacterial DNA were sufficiently confirmed by the PCR technique at different conditions. Conclusion: Overall, the FTA card method was observed to be a valid tool for nucleic acid purification for bacteria of animal origin in the form of culture or organ smears regardless of its Gram type and is used for a short time only 24 h for storage and transport of live bacteria specifically Gram-positive type. Moreover, the bacterial nucleic acid was intact after storage in –20°C for 3 months and was PCR amplifiable.</jats:p>

Lauren O’Brien, Nachshon Siboni, Justin R. Seymour et al.

Microbial Ecology • 2023

<jats:title>Abstract</jats:title><jats:p>Inflows from unregulated tributaries change the physical, chemical, and biotic conditions in receiving regulated rivers, impacting microbial community structure and metabolic function. Understanding how tributary inflows affect bacterial carbon production (BCP) is integral to understanding energy transfer in riverine ecosystems. To investigate the role of tributary inflows on bacterial community composition and BCP, a ~90th percentile natural flow event was sampled over 5 days along the Lachlan River and its tributaries within the Murray-Darling Basin of eastern Australia. Increased tributary inflows after rainfall corresponded with a significantly different and more diverse bacterial community in the regulated mainstem. The major contributor to this difference was an increase in relative abundance of bacterial groups with a potential metabolic preference for humic substances (Burkholderiaceae <jats:italic>Polynucleobacter,</jats:italic> Alcaligenaceae <jats:italic>GKS98 freshwater group</jats:italic>, Saccharimonadia) and a significant decrease in Spirosomaceae <jats:italic>Pseudarcicella</jats:italic>, known to metabolise algal exudates. Increases in orthophosphate and river discharge explained 31% of community change, suggesting a combination of resource delivery and microbial community coalescence as major drivers. BCP initially decreased significantly with tributary inflows, but the total load of carbon assimilated by bacteria increased by up to 20 times with flow due to increased water volume. The significant drivers of BCP were dissolved organic carbon, water temperature, and conductivity. Notably, BCP was not correlated with bacterial diversity or community composition. Tributary inflows were shown to alter mainstem bacterial community structure and metabolic function to take advantage of fresh terrestrial dissolved organic material, resulting in substantial changes to riverine carbon assimilation over small times scales.</jats:p>

John R. Frick

Journal of Petroleum Technology • 1972

<jats:p>Letters to JPT Forum are limited to a maximum of 750 words, including 200 words for each table and illustration. Acceptable subjects include new engineering ideas, progress reports from the laboratory and field, and descriptions of unique equipment, processes or practices. Letters should be sent to the Editor. SPE reserves the right to edit material to eliminate commercialism on remarks of a questionable nature.</jats:p> <jats:p>There is now, and has been for some 30 years, limited research in the area of bacteriological oil recovery. Several patent have been issued as a result of these works. However, concentrated effort is now being given to the problem of oil spills and their cleanup through bacterial methods. The time is right, therefore, to combine and accelerate our research in bacterial oil degradation, and to apply bacterial recovery methods. In this manner we can not only work toward improving the ecosystem but also derive new and economically feasible bacteriological oil recovery mechanisms. The purpose of this article is to briefly discuss bacteriological oil recovery, to stimulate thought, and to promote research in this area. promote research in this area. In the early 1940's, Zobell discovered that bacteria will release oil from sedimentary materials.'," In Dec., 1946, in conjunction with the American Petroleum Institute, he obtained a patent on a process Petroleum Institute, he obtained a patent on a process that involved the injection of anaerobic bacteria into an oil producing formation to increase oil recovery., He named the bacteria that he had isolated Desulfovibrio hydrocarbonociasticus, These bacteria are strict anaerobes and Zobell noted that they grow actively in salt solutions of 25,000 to 125,000 ppm dissolved solids. Also, they are able to tolerate high temperatures. In laboratory experiments Zobell found that the four mechanisms of bacterial oil release are:(1)production of gaseous carbon dioxide,(2)production production of gaseous carbon dioxide,(2)production of organic acids and detergents,(3)dissolution of carbonates in the rock, and(4)physical dislodgment of the oil.</jats:p> <jats:p>Zobell found that bacteria preferentially consume normal paraffins. More recently, with gas chromatography and other tools, this finding has been reaffirmed.</jats:p> <jats:p>Extensive tests of bacteria for oil recovery were made at the Bradford Laboratory of the Pennsylvania Grade Crude Oil Assn. during 1945 and 1946. The results were generally discouraging for bacterial applications in the Bradford area and it was therefore concluded at that time that field tests would not be feasible. However, this finding should now be reviewed and should not be assumed to hold true for present times and different locations. present times and different locations. So far, no results of field tests employing bacterial processes have been published in the U. S. literature. processes have been published in the U. S. literature. However, favorable results have been reported from tests conducted in Poland" and Hungary." The Polish observed oil production increases of 30 to 140 Polish observed oil production increases of 30 to 140 percent with pressure increases from 2 to 25 atm in percent with pressure increases from 2 to 25 atm in several shut-in wells. The pH of the reservoir water dropped from 8.7 to 6.4. There were small decreases in oil viscosity, and in some wells production increases continued for as long as 5 years. Also in Poland, bacteria of the Clostridium type have been isolated; these bacteria reduce heavy hydrocarbons in place to form lighter fractions and gases. Something of this nature could be of great significance to the Athabasca tar sands area. The possibility exists that bacteria can also be used for selective plugging. Since the bacteria and nutrients would be highly concentrated in thief zones, rapid, prolific growth would occur there. prolific growth would occur there. Plugging of the wellbore could be eliminated by separate-stage injection of spores and nutrients followed by a water pad to move the bacteria into the formation. Then a small amount of bactericide could stop the growth at the sand face. In this process the thief zone could be plugged, leaving the wellbore unaffected, and the sweep efficiency could be increased. Another possible application is in the underground production of water-thickening agents. production of water-thickening agents.</jats:p> <jats:p>JPT</jats:p> <jats:p>P. 1469</jats:p>

Jiakang Ru, Yixin Huo, Yu Yang

Frontiers in Microbiology • 2020

A growing accumulation of plastic wastes has become a severe environmental and social issue. It is urgent to develop innovative approaches for the disposal of plastic wastes. In recent years, reports on biodegradation of synthetic plastics by microorganisms or enzymes have sprung up, and these offer a possibility to develop biological treatment technology for plastic wastes. In this review, we have comprehensively summarized the microorganisms and enzymes that are able to degrade a variety of generally used synthetic plastics, such as polyethylene (PE), polystyrene (PS), polypropylene (PP), polyvinyl chloride (PVC), polyurethane (PUR), and polyethylene terephthalate (PET). In addition, we have highlighted the microbial metabolic pathways for plastic depolymerization products and the current attempts toward utilization of such products as feedstocks for microbial production of chemicals with high value. Taken together, these findings will contribute to building a conception of bio-upcycling plastic wastes by connecting the biodegradation of plastic wastes to the biosynthesis of valuable chemicals in microorganisms. Last, but not least, we have discussed the challenges toward microbial degradation and valorization of plastic wastes.