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Yuxi Liu, Jie Li, Junna Feng et al.
Journal Of Plant Ecology · 2025
Abstract Due to large-scale commercial logging and prolonged anthropogenic disturbances over the past decades, large tropical secondary forests have been converted into rubber plantations, which have substantial impacts on soil bacterial community via altering soil properties. However, how forest conversion affect soil bacterial community composition and diversity are still poorly understood. To address this, we compared the soil bacterial communities and physicochemical properties between typical secondary forests (SF) and rubber plantations (RP) in Hainan Island. The results showed that SF exhibited higher soil organic matter, total nitrogen, total carbon and pH compared to RP, particularly in the 0-10 cm layer. Besides, the soil bulk density in SF was lower than that in RP. The bacterial community composition and microbial networks were significantly varied between SF and RP. The dominant soil bacterial phyla in SF were Proteobacteria (27.37%–28.66%), followed by Acidobacteria (18.97%–19.82%), while Chloroflexi prevailed in RP (27.89%–28.45%), followed by Acidobacteria (20.93%–24.38%). Furthermore, SF exhibited more complex microbial networks owing to its higher edges, degree and links compared to RP. Meanwhile, bacterial community assembly in SF was primarily governed by deterministic processes, while stochastic processes dominated RP. The soil bacterial α-diversity in SF was higher than that in RP, which was primarily dominated by pH. Our findings demonstrate that converting secondary forests to rubber plantations does not favor soil microbial diversity and stability, as it decreases soil pH, which suggests that sustainable management strategies should prevent soil acidification in rubber plantations.
Siti Hasnawati Jamal, Nursyafiqah Jori Roslan, Noor Aisyah Ahmad Shah et al.
Solid State Phenomena · 2021
Cellulose nitrate has attracted great interest amongst researchers due to its uses in wide range of products including paint and gun propellant. Therefore, this work focuses on the synthesis of cellulose nitrate from two different sources of cellulose; plant and bacterial, in order to obtain high percentage of nitrogen content hence suitable for propellant application. The synthesis of cellulose nitrate was carried out via nitration method using nata de coco and kapok ( Ceiba pentadra L ) as a raw materials of cellulose. The samples were then characterized by elemental analysis, fourier transform infrared (FTIR) spectroscopy, x-ray diffraction and surface electron morphology (SEM). FTIR analysis showed the presence of NO 2 groups in both nitrocellulose proving that nitrocellulose was successfully synthesized by nitration method even though it was produced from different sources of cellulose. It is also showed nitrocellulose with high percentage of nitrogen content was obtained from bacterial cellulose, 12.69% rather than plant cellulose.
Lloyd J. Nadeau, Zhongqi He, Jim C. Spain
Applied and Environmental Microbiology · 2003
ABSTRACT Hydroxylamino aromatic compounds are converted to either the corresponding aminophenols or protocatechuate during the bacterial degradation of nitroaromatic compounds. The origin of the hydroxyl group of the products could be the substrate itself (intramolecular transfer mechanism) or the solvent water (intermolecular transfer mechanism). The conversion of hydroxylaminobenzene to 2-aminophenol catalyzed by a mutase from Pseudomonas pseudoalcaligenes JS45 proceeds by an intramolecular hydroxyl transfer. The conversions of hydroxylaminobenzene to 2- and 4-aminophenol by a mutase from Ralstonia eutropha JMP134 and to 4-hydroxylaminobenzoate to protocatechuate by a lyase from Comamonas acidovorans NBA-10 and Pseudomonas sp. strain 4NT were proposed, but not experimentally proved, to proceed by the intermolecular transfer mechanism. GC-MS analysis of the reaction products formed in H 2 18 O did not indicate any 18 O-label incorporation during the conversion of hydroxylaminobenzene to 2- and 4-aminophenols catalyzed by the mutase from R. eutropha JMP134. During the conversion of 4-hydroxylaminobenzoate catalyzed by the hydroxylaminolyase from Pseudomonas sp. strain 4NT, only one of the two hydroxyl groups in the product, protocatechuate, was 18 O labeled. The other hydroxyl group in the product must have come from the substrate. The mutase in strain JS45 converted 4-hydroxylaminobenzoate to 4-amino-3-hydroxybenzoate, and the lyase in Pseudomonas strain 4NT converted hydroxylaminobenzene to aniline and 2-aminophenol but not to catechol. The results indicate that all three types of enzyme-catalyzed rearrangements of hydroxylamino aromatic compounds proceed via intramolecular transfer of hydroxyl groups.
Alberto Rodriguez, Jamie A. Meadows, Ning Sun et al.
Microbial Cell Factories · 2021
Abstract Hydroxycinnamic acids such as p -coumaric acid (CA) are chemically linked to lignin in grassy biomass with fairly labile ester bonds and therefore represent a straightforward opportunity to extract and valorize lignin components. In this work, we investigated the enzymatic conversion of CA extracted from lignocellulose to 4-vinylphenol (4VP) by expressing a microbial phenolic acid decarboxylase in Corynebacterium glutamicum , Escherichia coli, and Bacillus subtilis . The performance of the recombinant strains was evaluated in response to the substrate concentration in rich medium or a lignin liquor and the addition of an organic overlay to perform a continuous product extraction in batch cultures. We found that using undecanol as an overlay enhanced the 4VP titers under high substrate concentrations, while extracting > 97% of the product from the aqueous phase. C. glutamicum showed the highest tolerance to CA and resulted in the accumulation of up to 187 g/L of 4VP from pure CA in the overlay with a 90% yield when using rich media, or 17 g/L of 4VP with a 73% yield from CA extracted from lignin. These results indicate that C. glutamicum is a suitable host for the high-level production of 4VP and that further bioprocess engineering strategies should be explored to optimize the production, extraction, and purification of 4VP from lignin with this organism.
H. L. Sadoff, Emel Celikkol, H. L. Engelbrecht
Proceedings of the National Academy of Sciences · 1970
A protease is elaborated by cells of Bacillus cereus during sporulation. This sporulation-specific enzyme, in a limited proteolysis, converts vegetative cell aldolase to spore aldolase.
Alejandra Calvo-Díaz, Xosé Anxelu G. Morán
Applied and Environmental Microbiology · 2009
ABSTRACT Leucine-to-carbon conversion factors (CFs) are needed for converting substrate incorporation into biomass production of heterotrophic bacteria. During 2006 we performed 20 dilution experiments for determining the spatiotemporal variability of empirical CFs in temperate Atlantic coastal waters. Values (0.49 to 1.92 kg C mol Leu −1 ) showed maxima in autumn to early winter and minima in summer. Spatially averaged CFs were significantly negatively correlated with in situ leucine incorporation rates ( r = −0.91) and positively correlated with phosphate concentrations ( r = 0.76). These relationships, together with a strong positive covariation between cell-specific leucine incorporation rates and carbon contents ( r = 0.85), were interpreted as a strategy to maximize survival through protein synthesis and low growth rates under nutrient limitation (low CFs) until favorable conditions stimulate cell division relative to protein synthesis (high CFs). A multiple regression with in situ leucine incorporation rates and cellular carbon contents explained 96% of CF variance in our ecosystem, suggesting their potential prediction from more easily measurable routine variables. The use of the theoretical CF of 1.55 kg C mol Leu −1 would have resulted in a serious overestimation (73%) of annual bacterial production rates. Our results emphasize the need for considering the temporal scale in CFs for bacterial production studies.
Kristin D. Bilyeu, Peiyu Zeng, Patricia Coello et al.
Plant Physiology · 2008
Abstract Phytic acid (PA) contains the major portion of the phosphorus in the soybean (Glycine max) seed and chelates divalent cations. During germination, both minerals and phosphate are released upon phytase-catalyzed degradation of PA. We generated a soybean line (CAPPA) in which an Escherichia coli periplasmic phytase, the product of the appA gene, was expressed in the cytoplasm of developing cotyledons. CAPPA exhibited high levels of phytase expression, ≥90% reduction in seed PA, and concomitant increases in total free phosphate. These traits were stable, and, although resulted in a trend for reduced emergence and a statistically significant reduction in germination rates, had no effect on the number of seeds per plant or seed weight. Because phytate is not digested by monogastric animals, untreated soymeal does not provide monogastrics with sufficient phosphorus and minerals, and PA in the waste stream leads to phosphorus runoff. The expression of a cytoplasmic phytase in the CAPPA line therefore improves phosphorus availability and surpasses gains achieved by other reported transgenic and mutational strategies by combining in seeds both high phytase expression and significant increases in available phosphorus. Thus, in addition to its value as a high-phosphate meal source, soymeal from CAPPA could be used to convert PA of admixed meals, such as cornmeal, directly to utilizable inorganic phosphorus.
Michael F. Coveney, Robert G. Wetzel
Applied and Environmental Microbiology · 1988
The relationship between bacterial growth and incorporation of [ methyl - 3 H]thymidine in oligotrophic lake water cultures was investigated. Prescreening, dilution, and addition of organic and inorganic nutrients were treatments used to prevent bacterivory and stimulate bacterial growth. Growth in unmanipulated samples was estimated through separate measurements of grazing losses. Both bacterial number and biovolume growth responses were measured, and incorporation of [ 3 H]thymidine in both total macromolecules and nucleic acids was assayed. The treatments had significant effects on conversion factors used to relate thymidine incorporation to bacterial growth. Cell number-based factors ranged from 1.1 × 10 18 to 38 × 10 18 cells mol of total thymidine incorporation −1 and varied with treatment up to 10-fold for the same initial bacterial assemblage. In contrast, cell biovolume-based conversion factors were similar for two treatment groups across a 16-fold range of [ 3 H]thymidine incorporation rates: 5.54 × 10 17 μm 3 mol of total thymidine incorporation −1 and 15.2 × 10 17 μm 3 mol of nucleic acid incorporation −1 . Much of the variation in cell number-based conversion factors was related to changes in apparent mean cell volume of produced bacteria. Phosphorus addition stimulated [ 3 H]thymidine incorporation more than it increased bacterial growth, which resulted in low conversion factors.
Laura Alonso‐Sáez, Jarone Pinhassi, Jakob Pernthaler et al.
Environmental Microbiology · 2010
Summary The suitability of applying empirical conversion factors (eCFs) to determine bacterial biomass production remains unclear because seawater cultures are usually overtaken by phylotypes that are not abundant in situ . While eCFs vary across environments, it has not been tested whether differences in eCFs are driven by changes in bacterial community composition or by in situ environmental conditions. We carried out seawater cultures throughout a year to analyse the correlation between eCFs and bacterial community structure, analysed by catalysed reporter deposition fluorescence in situ hybridization. Gammaproteobacteria usually dominated seawater cultures, but their abundance exhibited a wide range (25–73% of cell counts) and significantly increased with inorganic nutrient enrichment. Flavobacteria were less abundant but increased up to 40% of cells counts in winter seawater cultures, when in situ chlorophyll a was high. The correlations between eCFs and the abundance of the main broad phylogenetic groups ( Gamma‐, Alphaproteobacteria and Flavobacteria ) were significant, albeit weak, while more specific groups ( Alteromonadaceae and Rhodobacteraceae ) were not significantly correlated. Our results show that the frequent development of the fast‐growing group Alteromonadaceae in seawater cultures does not strongly drive the observed variations in eCFs. Rather, the results imply that environmental conditions and the growth of specific phylotypes interact to determine eCFs.
R. K. Clayton
Photochemistry and Photobiology · 1962
Summary Reversible light‐induced alteration of a special component of bacteriochlorophyll (BChl,) is observed in bacterial chromatophores. The alteration involves bleaching of the long‐wave absorption band at 870–890 mp and a blue shift of the band at 800 mp. Assuming that the altered BChl, molecule loses all of its long‐wave absorption, and that the extinction coefficient of this band is equal to that of the corresponding band in the major component of BChl, a quantum requirement could be computed for the light‐induced change. It was found with most preparations that two to four quanta suffice for the alteration of one BChl, molecule, even in dried chromatophores at 1° K. This result is taken as supporting evidence for the importance of light‐induced BChl, conversion in photosynthesis. It also shows that BChl, is effective as an energy sink in the chromatophore.
AJ Ramsay, RE Stannard, GJ Churchman
Soil Research · 1986
Water-stable aggregates and soil bacteria were studied from May to January in a field trial comparing soil structure under three treatments: wheat sown in ploughed soil, direct-drilled wheat and long-term grass. During the trial, both the proportion and size of macroaggregates (> 250 �m) tended to increase. These increases were accompanied by decreases in the proportions of particles in all smaller size ranges, including <2 �m, in the early part of the growing season, but, over summer, larger macroaggregates (> 2000 �m) increased at the expense of particles between 2000 and 63 �m. The highest proportion of larger macroaggregates occurred under grass, in all except the spring sampling, while the lowest proportion occurred in the ploughed soils. Numbers of bacteria, obtained by direct microscopy, were higher in the ploughed soil soon after ploughing than in the direct-drilled soil, but no other treatment effect was detected. In all plots, numbers of bacteria were lowest in November when the soil was the driest. There were up to twice as many bacteria per g of < 20 �m diameter fraction soil compared with the rest of the soil. Seasonal changes in the bacterial population of the <20 �m diameter fraction did not follow the changes in the whole soil.
kun li, xu han, ruiqiang ni et al.
Research Square · 2020
Abstract Background: Robinia pseudoacacia is a widely planted pioneer tree species in reforestations on barren mountains in northern China. Because of its nitrogen-fixing ability, it can play a positive role in soil and forest restoration. After clear-cutting of planted stands, R. pseudoacacia stands become coppice plantations. The impacts of shifting from seedling to coppice plantations on soil bacterial community and soil properties have not been well described. This study aims to quantify how soil properties and bacterial community composition vary between planted seedling versus coppice stands. Methods : Three 20×20 m plots were randomly selected in each seedling and coppice stand. The bulk soil and rhizosphere soil were sampled in the nine above-mentioned sample plots in the summer of 2017. Bulk soil was sampled at 10 cm from the soil surface using a soil auger. Rhizosphere soil samples were collected by brush. The soil samples were transported to the laboratory for chemical analysis and bacterial community composition and diversity was obtanied through DNA extraction, 16S rRNA gene amplification and high throughput sequencing. Results : The results showed that, compared to seedling plantations, soil quality decreased significantly in coppice stands, but without affecting soil exchangeable Mg 2+ and K + . Total carbon (C) and nitrogen (N) were lower in the rhizosphere than in bulk soil, whereas nutrient availability showed an opposite trend. The conversion from seedling to coppice plantations was also related to significant differences in soil bacterial community structure and to the reduction of soil bacterial α-diversity. Principal component analysis (PCA) showed that, bacterial community composition was similar in both bulk and rhizosphere soils in second generation coppice plantations. Specially, the conversion from seedling to coppice increased the relative abundance of Proteobacteria and Rhizobium , but reduced that of Actinobacteria , which may result in a decline of soil nutrient availability. Mantel tests revealed that C, N, Soil organic matter (SOM), nitrate nitrogen (NO 3 - -N) and available phosphorus positively correlated with bacterial community composition, while a variation partition analysis (VPA) showed that NO 3 - -N explained a relatively greater proportion of bacterial distribution (15.12%), compared with C and SOM. Surprinsingly, N showed no relationship with bacterial community composition, which may be related to nitrogen transportation. Conclusions : The conversion from seedling to coppice stands reduced soil quality and led to spatial-temporal homogenization of the soil bacterial community structure in both the rhizosphere and bulk soils. Such imbalance in microbial structure can accelerate the decline of R. pseudoacacia . This may affect the role of R. pseudoacacia coppice stands in soil and forest restoration of barren lands in mountain areas.
Melih Güzel
Biomass Conversion and Biorefinery · 2025
Abstract The short shelf life of bread can be attributed to changes in its textural and sensory properties, a process termed staling, and large amounts of bread residue and waste are generated daily. Because the main component of bread is starch, the use of bread wastes as a substrate for bacterial cellulose (BC) production can significantly contribute to valorisation and reuse of wastes. This study aimed to investigate the BC production potential of various stale breads, convert these wastes into usable forms for food and other industries, and increase their economic value. Stale breads were hydrolyzed with dilute acid, and BC-producing bacteria from Kombucha tea were isolated and identified as Gluconobacter oxydans MG2021 (GO). BCs were produced from bread hydrolysates with GO and Komagataeibacter hansenii GA2016 (KH), and their properties were examined. The results indicated that stale breads represented a good source for BC production, as high BC yields were obtained using GO (8.81%–25.02%) and all BCs had superior properties such as high crystallinity (75.96%–91.39%), thermal stability, liquid holding capacity, and fine fibers (40.16–85.39 nm). This study demonstrated that bread wastes could be used as a low-cost substrate for large-scale BC production, and the abundance of bread wastes demonstrated their potential as a resource for commercial BC producers.
Dalaq Aiysha, Zakia Latif
Journal of Basic Microbiology · 2022
Abstract Microbial enzymatic degradation of biowaste is a sustainable and environmentally friendly solution for eliminating biowaste pollution. It is the underlying cause of the ever‐increasing demand for harnessing multipurpose microbes to work as an entity under given complex processes. Twelve bacterial strains of bovine manure were evaluated for their hydrolytic enzyme activity and optimization. Six enzymes; cellulase, amylase, pectinase, chitinase, protease, and gelatinase were selected based on their corresponding abundant biowaste, that is, cellulose, proteinaceous, chitin, and polymeric starchy biowaste. The preliminary qualitative screening was followed by quantitative enzyme production as well as optimal enzyme production conditions. Irrespective of their sample source and origin, all strains showed the highest enzyme production when grown at 40°C for 72 h with pH 7. Comparatively, among the selected enzymes, strains were higher producers of cellulase, protease, and gelatinase. The present study reported the first time Brevibacillus parabrevis (DZ.15) as pectinase producer, Achromobacter spanius (DZ.1) as amylase‐protease‐chitinase producer, Achromobacter piechaudii (DZ.12) as pectinase‐chitinase‐gelatinase producer, and two Achromobacter kerstersii (DZ.16 and DZ.17) as pectinase‐chitinase producers. Therefore, this study suggested that bovine manure microbes exhibiting novel potential can be used for hydrolysis of environmental biowaste.
kun li, xu han, ruiqiang ni et al.
Research Square · 2020
Abstract Background: Robinia pseudoacacia is a widely planted pioneer tree species in reforestations on barren mountains in northern China. Because of its nitrogen-fixing ability, it can play a positive role in soil and forest restoration. After clear-cutting of planted stands, R. pseudoacacia stands become coppice plantations. The impacts of shifting from seedling to coppice stands on soil bacterial community and soil properties have not been well described. This study aims to quantify how soil properties and bacterial community composition vary between planted seedling versus coppice stands. Methods : Nine 20×20 m plots were randomly selected in seedling and coppice stands. The bulk soil and rhizosphere soil were sampled in summer 2017. Bulk soil was sampled at 10 cm from the soil surface using a soil auger. Rhizosphere soil samples were collected using a brush. The soil samples were transported to the laboratory for chemical analysis, and bacterial community composition and diversity was obtained through DNA extraction, 16S rRNA gene amplification and high-throughput sequencing. Results : The results showed that, compared to seedling plantations, soil quality decreased significantly in coppice stands, but without affecting soil exchangeable Mg 2+ and K + . Total carbon (C) and nitrogen (N) were lower in the rhizosphere than in bulk soil, whereas nutrient availability showed an opposite trend. The conversion from seedling to coppice plantations was also related to significant differences in soil bacterial community structure and to the reduction of soil bacterial α-diversity. Principal component analysis (PCA) showed that bacterial community composition was similar in both bulk and rhizosphere soils in second generation coppice plantations. Specially, the conversion from seedling to coppice stands increased the relative abundance of Proteobacteria and Rhizobium , but reduced that of Actinobacteria , which may result in a decline of soil nutrient availability. Mantel tests revealed that C, N, Soil organic matter (SOM), nitrate nitrogen (NO 3 - -N) and available phosphorus positively correlated with bacterial community composition, while a variation partition analysis (VPA) showed that NO 3 - -N explained a relatively greater proportion of bacterial distribution (15.12%), compared with C and SOM. Surprisingly, N showed no relationship with bacterial community composition, which may be related to nitrogen transportation. Conclusions : The conversion from seedling to coppice stands reduced soil quality and led to spatial-temporal homogenization of the soil bacterial community structure in both the rhizosphere and bulk soils. Such imbalance in microbial structure can accelerate the decline of R. pseudoacacia . This may affect the role of R. pseudoacacia coppice stands in soil and forest restoration of barren lands in mountain areas.
J E Vancauwenberge, P J Slininger, R J Bothast
Applied and Environmental Microbiology · 1990
beta-hydroxypropionaldehyde (3-HPA) can be oxidized to acrylic acid, an industrially important chemical used in the manufacture of synthetic plastics and other polymers. Of 19 genera and 55 strains tested, 3 Klebsiella and 2 Enterobacter strains produced 3-HPA. The most efficient strain was Klebsiella pneumoniae NRRL B-4011. Under optimum conditions (28 degrees C; 40 g of semicarbazide hydrochloride per liter, 70 g of glycerol per liter; and pH 6.0), 3.1 g of B-4011 cells per liter accumulated 22 g of 3-HPA per liter at a specific rate of 0.83 g/g per h; however, 14.5 g of cells per liter accumulated 46 g of 3-HPA per liter at a specific rate of 0.41 g/g per h.
Zhikang Wang, Chunlin Li, Zengchao Geng et al.
Research Square · 2023
Abstract Objective: The objective of this study is to address the research gap regarding the diversity and life strategies of organisms inhabiting soil environments formed by new restoration techniques such as aggregate spray-seeding (ASS), which currently remain unclear. Methods: We conducted a comparison between the ASS restoration area (SRA) and the natural vegetation area (NVA), as well as the ASS forest conversion area (FCA) and the traditional afforestation area (TAA) on Triangle Island, China. Environmental DNA sequencing was employed to analyze the diversity and life strategies of soil bacterial communities during both the summer and winter seasons. Results: The SRA and FCA showed significantly higher Chao1 index and relative abundance of r-strategy bacteria compared to NVA and TAA, along with lower DNA guanine-cytosine (GC) content. The soil bacterial communities of NVA and TAA were similar to each other, as were those of SRA and FCA. Proteobacteria and Acidobacteriota were found to be the dominant phyla in our studied soils, accounting for 67.83-76.54% of the total relative abundance. Proteobacteria had a higher relative abundance in summer, while Acidobacteriota had a higher relative abundance in winter. GC content exhibited a negative correlation (p < 0.0001) with the relative abundance of r-strategy bacteria and a positive correlation (p < 0.01) with the relative abundance of K-strategy bacteria. Conclusions: Our study demonstrates the impact of ASS application on the diversity and life strategy of soil bacterial communities, while also confirming the correlation between bacterial GC content and life strategy. These findings provide a basis for regulating soil microbial communities in ecological restoration projects.
Kun Li, Xu Han, Ruiqiang Ni et al.
Research Square · 2020
Abstract Background: Robinia pseudoacacia is a widely planted pioneer tree species in reforestations on barren mountains in northern China. Because of its nitrogen-fixing ability, it can play a positive role in soil and forest restoration. After clear-cutting of planted stands, R. pseudoacacia stands become coppice plantations. The impacts of shifting from seedling to coppice plantations on soil bacterial community and soil properties have not been well described. This study aims to quantify how soil properties and bacterial community composition vary between planted seedling versus coppice stands. Methods: Three 20 × 20 m plots were randomly selected in each seedling and coppice stand. The bulk soil and rhizosphere soil were sampled in the nine above-mentioned sample plots in the summer of 2017. Bulk soil was sampled at 10 cm from the soil surface using a soil auger. Rhizosphere soil samples were collected by brush. The soil samples were transported to the laboratory for chemical analysis and bacterial community composition and diversity was obtanied through DNA extraction, 16S rRNA gene amplification and high throughput sequencing. Results: The results showed that, compared to seedling plantations, soil quality decreased significantly in coppice stands, but without affecting soil exchangeable Mg 2+ and K 2+ . Total carbon (C) and nitrogen (N) were lower in the rhizosphere than in bulk soil, whereas nutrient availability showed an opposite trend. The conversion from seedling to coppice plantations was also related to significant differences in soil bacterial community structure and to the reduction of soil bacterial α-diversity. Principal component analysis (PCA) showed that, bacterial community composition was similar in both bulk and rhizosphere soils in second generation coppice plantations. Specially, the conversion from seedling to coppice increased the relative abundance of Proteobacteria and Rhizobium , but reduced that of Actinobacteria , which may result in a decline of soil nutrient availability. Mantel tests revealed that C, N, Soil organic matter (SOM), nitrate nitrogen (NO 3 − -N) and available phosphorus positively correlated with bacterial community composition, while a variation partition analysis (VPA) showed that NO 3 − -N explained a relatively greater proportion of bacterial distribution (15.12%), compared with C and SOM. Surprinsingly, N showed no relationship with bacterial community composition, which may be related to nitrogen transportation. Conclusions: The conversion from seedling to coppice stands reduced soil quality and led to spatial-temporal homogenization of the soil bacterial community structure in both the rhizosphere and bulk soils. Such imbalance in microbial structure can accelerate the decline of R. pseudoacacia . This may affect the role of R. pseudoacacia coppice stands in soil and forest restoration of barren lands in mountain areas.
Bahaa A. Hemdan, Mehrez E. El-Naggar, Sh. E. Abd-Elgawad et al.
Biomass Conversion and Biorefinery · 2024
Abstract Recently, the development of skin barrier depend on wound healing, which is one of the most complicated biological processes. As an alternative to conventional antibiotics, nanoparticles (NPs) have become more utilized generally to attack bacteria. Due to their distinct characteristics, potential microbicidal action, and ability to speed up the wound healing process, zinc oxide nanoparticles (ZnO-NPs) have attracted much attention. Biological techniques can solve the restrictions of both physical and chemical approaches for nanoparticles synthesis. Because it does not require expensive chemicals, high temperatures, or a lot of time, biological synthesis is relatively easy, inexpensive, and environmentally benign. The secondary metabolic extract from Escherichia coli was used in this study to biologically synthesize three distinct quantities of ZnO-NPs, which were then assessed for their effectiveness in wound healing and bacterial infection prevention. The biofabricated ZnO-NPs were fully characterized in terms of particle shape, morphology, and stability against aggregation. Depending on the concentration of the utilized zinc salt, three different samples were fabricated biologically, nominated as ZnO-NPs-1, ZnO-NPs-2, and ZnO-NPs-3. The findings of Uv-vis absorption peaks were obtained at 352 nm, demonstrating the preparation of ZnO-NPs. The results demonstrated the formation of ZnO-NPs with an average particle size of 79.19, 79.83 and 91.57 nm for the three prepared samples (ZnO-NPs-1, ZnO-NPs-2, and ZnO-NPs-3), respectively. Additionally, these samples of ZnO-NPs exhibited zeta potential values around −34.3, −33.7, and −33.4 mV, respectively. Energy dispersive X-ray confirmed the successful formation of ZnO-NPs. It was also observed from the obtained results that, ZnO-NP-3 showed superior antimicrobial potential against selected skin infectious microbes. The effective killing dosage of ZnO-NPs-3 was recorded to be 40 mg/L which can eliminate microbial growth. The dysregulation of skin flora significantly influences the etiology of inflammatory skin disorders.
Asmita Gaikwad, Kavita Jadhav, Shubhada Nayak
Current Agriculture Research Journal · 2023
Lignocellulosic biomass abundantly and ubiquitously occupies the earth. However, their complex molecular structure prevents their use as a source of organic material for fermentable sugars and nutrients to be used as foods, fertilizers and biofuels. For an efficient carbon cycle, microbial enzymes play a key role in slow biodegradation of lignocellulosic wastes in nature. Microbiological applications can enhance the rate of biodegradation to utilize agro-industrial and organic municipal solid wastes, containing up to 50% lignocellulose substrates, as an inexpensive and sustainable source of plant nutrients. With this hypothesis, the current study was carried out to prepare a consortium of lignocellulose degrading bacteria and use it to convert lignocellulosic substrates in garden, sugarcane, rice, cotton and fruit waste into biofertilizer. Overall, 7-14% reduction in cellulose and 3-6% reduction in lignin content, along with decrease in pH was observed on treatment of above wastes with microbial consortium in 42 days. In spite of the low conversion rates observed in our study, better root, shoot as well as leaf development was observed in moong seedlings grown in soil amended with biofertilizer (3:1 ratio) as compared to controls. Another interesting observation was the biofertilizers with low pH prepared from sugarcane wastes (pH 3.1) and fruit wastes (pH 3.6) supported plant growth more efficiently as compared to other biofertilizers (pH 5.0 to 5.7). Thus, in addition to feasible conversion of lignocellulosic wastes into biofertilizer, our study further suggests the use of selective wastes as raw material depending on the preference of plants for slightly acidic to neutral soil pH for growth.
C W Birky, J B Walsh
Genetics · 1992
Abstract We investigate the possibility that differences between synonymous substitution rates of organelle and bacterial genes differing only in copy number may be due to conversion bias. We find that the rather large observed difference in the synonymous rates between genes in the single copy and inverted-repeat regions of chloroplasts can be accounted for by a very small bias against new mutants. More generally, differences in the within-organelle fixation probability result in different apparent mutation rates as measured by the expected rate of appearance of cells homoplasmic for new mutants. Thus, differences in intracellular population parameters rather than molecular mechanisms can account for some variation in the apparent mutation rates of organelle genes, and possibly in other systems with variable numbers of gene copies. On the other hand, our analysis suggests that conversion bias is not a likely explanation for relatively low mutation rates observed near the replication origin of bacterial chromosomes.
W Wegst, U Tittmann, J Eberspächer et al.
Biochemical Journal · 1981
Strain E of chloridazon-degrading bacteria, when grown on L-phenylalanine accumulates cis-2,3-dihydro-2,3-dihydroxyphenylalanine. In experiments with resting cells and during growth the bacterium converts the aromatic carboxylic acids phenylacetate, phenylpropionate, phenylbutyrate and phenyl-lactate into the corresponding cis-2,3-dihydrodiol compounds. The amino acids L-phenylalanine, N-acetyl-L-phenylalanine and t-butyloxycarbonyl-L-phenylalanine were also transformed into dihydrodiols. All seven dihydrodiols, thus obtained, were characterized both by conventional analytical techniques and by the ability to serve as substrates for a cis-dihydrodiol dehydrogenase.
Sohta A. Ishikawa, Ryoma Kamikawa, Yuji Inagaki
Scientific Reports · 2015
Abstract Bacteria require two class-I release factors, RF1 and RF2, that recognize stop codons and promote peptide release from the ribosome. RF1 and RF2 were most likely established through gene duplication followed by altering their stop codon specificities in the common ancestor of extant bacteria. This scenario expects that the two RF gene families have taken independent evolutionary trajectories after the ancestral gene duplication event. However, we here report two independent cases of conversion between RF1 and RF2 genes ( RF1 - RF2 gene conversion), which were severely examined by procedures incorporating the maximum-likelihood phylogenetic method. In both cases, RF1 - RF2 gene conversion was predicted to occur in the region encoding nearly entire domain 3, of which functions are common between RF paralogues. Nevertheless, the ‘direction’ of gene conversion appeared to be opposite from one another—from RF2 gene to RF1 gene in one case, while from RF1 gene to RF2 gene in the other. The two cases of RF1-RF2 gene conversion prompt us to propose two novel aspects in the evolution of bacterial class-I release factors: (i) domain 3 is interchangeable between RF paralogues and (ii) RF1-RF2 gene conversion have occurred frequently in bacterial genome evolution.
Ramya Veerubhotla, Aditya Bandopadhyay, Suman Chakraborty
bioRxiv (Cold Spring Harbor Laboratory) · 2022
Abstract The recent COVID-19 crisis necessitated the universal use of Personal Protection Equipment (PPE) kits, generating tons of plastic wastes that inevitably lead to environmental damage. Circumventing the challenges stemming from such undesirable non-degradability on disposal, here we present an eco-friendly, robust, yet inexpensive and equipment-free method of growing biodegradable PPE fabrics by the fermentation of locally-sourced organic feed stocks in a rural livelihood. Using a pre-acclimatized symbiotic culture, we report the production of a high yield (up to 3.2 g fabric/g substrate) of bacterial cellulose, a biopolymer matrix, obtained by bacterial weaving. This membrane has an intricate, self-assembled, nano-porous 3D architecture formed by randomly oriented cellulose fibres. Scanning electron microscopy reveals that the pore size of the membrane turns out to be in the tune of 140 nanometers on the average, indicating that it can filter out viruses effectively. In-vitro results demonstrate assured breathability through the membrane for a filter thickness of approximately 5 microns. When subjected to soil degradation, the fabrics are seen to disintegrate rapidly and fully decompose within 15 days. With a favourable cost proposition of less than 1 US$ per meter square of the developed fabric unit, our approach stands out in providing a unique sustainable, and production-ready alternative to synthetic PPE fabrics, solving community healthcare and environmental crisis, and opening up new avenues sustainable under-served livelihood at the same time. Graphical abstract
E. R. Blakley
Canadian Journal of Microbiology · 1972
An unidentified bacterium degrades p-hydroxyphenylacetic acid by a pathway which involves homogentisic acid as an intermediate. Extracts of cells grown on p-hydroxyphenylacetic acid contain an enzyme that converts p-hydroxyphenylacetic acid to homogentisic acid. The enzyme has been partially purified by ammonium sulfate fractionation and some of its properties examined. The complete oxidation of 1 mole of p-hydroxyphenylacetic acid requires 1 mole of either NADH or NADPH, and 1 mole of oxygen, and results in the production of 1 mole of homogentisic acid. The enzyme preparation has a high specificity for p-hydroxyphenylacetic acid, but has about 25% activity with p-hydroxyphenylpyruvic acid.
Irina Zanina, Eugenia Kostromina, Natalia Stuzhenko et al.
E3S Web of Conferences · 2020
The article presents the results of an analysis of modern research in the field of organic waste processing. To solve the problem, anaerobic bioconversion method was chosen. The data of experimental laboratory experiments on the selection of a consortium of microorganisms’ methanizing waste from poultry farms with maximum efficiency are presented.
Manuel Layer, Antoine Brison, Mercedes Garcia Villodres et al.
Environmental Science: Water Research & Technology · 2022
Particulate organic substrate (X B ) represents the major fraction of organic substrate in low-strength municipal wastewater (MWW) but its hydrolysis, conversion and utilisation in aerobic granular sludge (AGS) are not well understood.
H. A. Mousa, M. G. Abaid
Eastern Mediterranean Health Journal · 2000
From 1983 to 1989, 110 cases of haematogenous osteomyelitis were studied retrospectively. The most commonly affected were children under 1 year. No adult cases were reported. Staphylococcus aureus was isolated from 72.7% of cases. During 1992-1997, 80 cases were studied prospectively. The most commonly affected were children aged 9 years. This group included 19 adults. S. aureus was isolated from 43.7% of the cases. There was a clear difference in the incidence of S. aureus and age presentation in the cases before and after the Gulf conflict. Working children and malnutrition might have caused changes in the infecting organisms and age presentation in recent years
Van Bon Nguyen, San-Lang Wang
Marine Drugs · 2017
Six kinds of chitinous materials have been used as sole carbon/nitrogen (C/N) sources for producing α-glucosidase inhibitors (aGI) by Paenibacillus sp. TKU042. The aGI productivity was found to be highest in the culture supernatants using demineralized crab shell powder (deCSP) and demineralized shrimp shell powder (deSSP) as the C/N source. The half maximal inhibitory concentration (IC50) and maximum aGI activity of fermented deCSP (38 µg/mL, 98%), deSSP (108 µg/mL, 89%), squid pen powder (SPP) (422 µg/mL, 98%), and shrimp head powder (SHP) (455 µg/mL, 92%) were compared with those of fermented nutrient broth (FNB) (81 µg/mL, 93%) and acarbose (1095 µg/mL, 74%), a commercial antidiabetic drug. The result of the protein/chitin ratio on aGI production showed that the optimal ratio was 0.2/1. Fermented deCSP showed lower IC50 and higher maximum inhibitory activity than those of acarbose against rat intestinal α-glucosidase.
Robert J. Theriault, Thomas H. Longfield
Applied Microbiology · 1967
Approximately 700 cultures of various types were examined for their ability to hydroxylate acetanilide. The major product formed by unidentified Streptomyces species RJTS-539 was identified as 4′-hydroxyacetanilide ( N -acetyl- p -aminophenol). This culture gave a peak yield of 405 mg per liter from 1,000 mg of acetanilide per liter. Considerably lower yields of 4′-hydroxyacetanilide were isolated from S. cinnamoneus NRRLB-1285. The major conversion product of acetanilide formed by Amanita muscaria F-6 was identified as 2′-hydroxyacetanilide, with a peak yield of 433 mg per liter from 1,000 mg per liter of substrate. A small amount of 4′-hydroxyacetanilide was also formed. Six other Streptomyces cultures formed small amounts of one or two products identical or similar to 2′-hydroxyacetanilide or 4′-hydroxyacetanilide as determined by thin-layer chromatography and ultraviolet spectra.
Tse-Yi Wang, Chien-Hao Su, Huai-Kuang Tsai
Bioinformatics · 2011
Abstract Motivation: Metagenomics involves sampling and studying the genetic materials in microbial communities. Several statistical methods have been proposed for comparative analysis of microbial community compositions. Most of the methods are based on the estimated abundances of taxonomic units or functional groups from metagenomic samples. However, such estimated abundances might deviate from the true abundances in habitats due to sampling biases and other systematic artifacts in metagenomic data processing. Results: We developed the MetaRank scheme to convert abundances into ranks. MetaRank employs a series of statistical hypothesis tests to compare abundances within a microbial community and determine their ranks. We applied MetaRank to synthetic samples and real metagenomes. The results confirm that MetaRank can reduce the effects of sampling biases and clarify the characteristics of metagenomes in comparative studies of microbial communities. Therefore, MetaRank provides a useful rank-based approach to analyzing microbiomes. Contact: hktsai@iis.sinica.edu.tw Supplementary Information: Supplementary data are available at Bioinformatics online.
S. Patrabansh, M. Madan
Acta Biotechnologica · 1995
Abstract A number of agricultural residues such as Saccharum munja Roxb. (Sarkanda), Oryza sativa L. (Paddy straw, as the control), Vinna unguiculata (L.) Walp (Cowpeas), Abelmoschus esculentum (L.) Moench (Lady's finger), Zea mays L. (Maize) and Cyamopsis tetragonoloba (L.) Taub. (Guar) were used for the cultivation of Pleurotus sajor‐caju (Fr.) Singer. The biological efficiency of the fruit bodies of Pleurotus sajor‐caju from the above mentioned substrates were found to be 13.47, 11.20, 8.37, 8.31, 6.87, and 6.08 percent, respectively. S. munja and paddy straw were found to be the best substrates for the growth of P. sajor‐caju followed by Z. mays, V. unguiculata, A. esculentum , and C. tetragonoloba .
Filip Boratyński, Ewa Szczepańska, Jakub Pannek et al.
Catalysts · 2015
It has been shown that whole cells of different strains of yeast catalyze stereoselective oxidation of meso diols to the corresponding chiral lactones. Among screening-scale experiments, Candida pelliculosa ZP22 was selected as the most effective biocatalyst for the oxidation of monocyclic diols 3a–b with respect to the ratio of high conversion to stereoselectivity. This strain was used in the preparative oxidation, affording enantiomerically-enriched isomers of lactones: (+)-(3aR,7aS)-cis-hexahydro-1(3H) -isobenzofuranone (2a) and (+)-(3aS,4,7,7aR)-cis-tetrahydro-1(3H)-isobenzofuranone (2b). Scaling up the culture growth, as well as biotransformation conditions has been successfully accomplished. Among more bulky substrates, bicyclic diol 3d was totally converted into enantiomerically-pure exo-bridged (+)-(3aR,4S,7R,7aS)-cis-tetrahydro-4,7-methanoisobenzofuran -1(3H)-one (2d) by Yarrovia lipolytica AR71. Microbial oxidation of diol 3f by Candida sake AM908 and Rhodotorula rubra AM4 afforded optically-pure cis-3-butylhexahydro-1(3H) -isobenzofuranone (2f), however with low conversion.
Ch. Tamm
Angewandte Chemie International Edition in English · 1962
Abstract Micro‐organisms form enzymes that catalyze many reactions which are difficult to carry out in the laboratory or which involve many steps. Enzymes even react with substances which are normally foreign to them. The frequently high stereospecificity of microbiological reactions is of particular significance. The most important types of reactions are: hydroxylations, dehydrogenations (oxidations), and hydrogenations (reductions), cleavage of ester and C‐C bonds, and transglycosidations. The variety of the compounds converted is extremely great.
Paola Iovieno, Riccardo Scotti, Massimo Zaccardelli
Agriculture · 2021
In the National park of Cilento, Vallo di Diano and Alburni (South Italy), a portion of a chestnut forest was converted in 2012 into an agricultural system in order to crop a local variety of bean. We investigated the effect over time of the conversion on the functional diversity of the soil microbial community by two different approaches: the catabolic response profile, based on the short time CO2 evolution induced by 25 simple organic substrates and the Biolog community level physiological profile (CLPP), based on the growth of microorganisms on 31 different substrates. The soils were sampled at 13, 17, 29, 41 and 49 months after the soil use change. The results showed that the soil use change did not produce evident modifications of the substrate utilization patterns, but rather a general decrease in the activity in the agricultural soils, as a consequence of the reduction in organic matter content. The results also showed seasonal effects on the substrate utilization profiles and on the calculated functional diversity indexes. The two approaches appeared to be complementary: Degens catabolic response profile was more able to discriminate between the two systems, whereas the Biolog was more able to highlight the variability among samplings.
Galal T. Maatooq
Zeitschrift für Naturforschung C · 2002
The biotransformation of partheniol by the fungus Calonectria decora ATCC 14767, produced six metabolites. These metabolites are; aromadendr-1(10)-en-8α -ol; 5(9),6-tricyclohumul- 1(10)-en-8α-ol; 4,15-didehydro-6-bicyclohumulan-8α,10α-diol; 5(9),6-tricyclohumulan- 4α,8α-diol; maalian-1α,8α-diol and 14-epi-1(4)-epoxymaalian-8α-ol. The identities of these metabolites were established by different spectroscopic measurements.
Y.-S. Lin, V. B. Heuer, T. G. Ferdelman et al.
· 2010
Abstract. In anoxic environments, volatile methylated sulfides including methanethiol (MT) and dimethyl sulfide (DMS) link the pools of inorganic and organic carbon with the sulfur cycle. However, direct formation of methylated sulfides from reduction of dissolved inorganic carbon has previously not been demonstrated. During examination of the hydrogenotrophic microbial activity at different temperatures in the anoxic sediment from Lake Plußsee, DMS formation was detected at 55 °C and was enhanced when bicarbonate was supplemented. Addition of both bicarbonate and H2 resulted in the strongest stimulation of DMS production, and MT levels declined slightly. Addition of methyl-group donors such as methanol and syringic acid or methyl-group acceptors such as hydrogen sulfide did not enhance further accumulation of DMS and MT. The addition of 2-bromoethanesulfonate inhibited DMS formation and caused a slight MT accumulation. MT and DMS had average δ13C values of −55‰ and −62‰, respectively. Labeling with NaH13CO3 showed that incorporation of bicarbonate into DMS occurred through methylation of MT. H235S labeling demonstrated a microbially-mediated, but slow, process of hydrogen sulfide methylation that accounted for <10% of the accumulation rates of DMS. Our data suggest: (1) methanogens are involved in DMS formation from bicarbonate, and (2) the major source of the 13C-depleted MT is neither bicarbonate nor methoxylated aromatic compounds. Other possibilities for isotopically light MT, such as demethylation of 13C-depleted DMS or other organic precursors such as methionine, are discussed. This DMS-forming pathway may be relevant for anoxic environments, such as hydrothermally influenced sediments and fluids and sulfate-methane transition zones in marine sediments.
Cheng Li, Keaton Lesnik, Hong Liu
Energies · 2013
Biodiesel has gained a significant amount of attention over the past decade as an environmentally friendly fuel that is capable of being utilized by a conventional diesel engine. However, the biodiesel production process generates glycerol-containing waste streams which have become a disposal issue for biodiesel plants and generated a surplus of glycerol. A value-added opportunity is needed in order to compensate for disposal-associated costs. Microbial conversions from glycerol to valuable chemicals performed by various bacteria, yeast, fungi, and microalgae are discussed in this review paper, as well as the possibility of extending these conversions to microbial electrochemical technologies.
Yizhen Wang
MATEC Web of Conferences · 2025
This paper highlights developments in microbial electrosynthesis (MES), metabolic engineering, and photosynthetic biohybrid systems (PBSs) for biofuel production, which offer a sustainable solution to lessen dependency on fossil fuels and the emission of greenhouse gases. MES uses electroactive microbes to convert CO2 into ethanol, methane, and other fuels using renewable electricity while integrating wastewater treatment; metabolic engineering improves CO2 fixation by redesigning microbial pathways; and PBSs combine inorganic semiconductors with biological catalysts to improve solar energy conversion. Methane synthesis through hydrogenotrophic methanogenesis and ethanol production via acetyl-CoA pathways are examples of targeted biofuel synthesis. However, the overall energy yields remain suboptimal for large-scale deployment. Slow reaction rates, expensive hydrogen, and fluctuating CO2 fixation efficiencies in microalgae systems are among the difficulties that are impacted by reactor design and operating factors. Process optimization and strain engineering innovations hold promise for scalability. However, further research is required due to the infrastructural requirements and economic viability of CO2 capture and hydrogen delivery. Realizing the full potential of microbial CO2 conversion technologies in reaching carbon neutrality will require addressing these technological and financial obstacles through interdisciplinary methods.
N. Yemashova, S. Kalyuzhnyi
Water Science and Technology · 2006
Four selected azo dyes (acid orange 6, acid orange 7, methyl orange and methyl red) were completely decolourised in the presence of anaerobic granular sludge, while only methyl red was degraded in aerobic conditions using a conventional activated sludge. Additional experiments with culture broth devoid of cells showed that anaerobic decolourisation of azo dyes was performed by extracellular reducing agents produced by anaerobic bacteria. This was further confirmed by abiotic experiments with sulphide and NADH. The presence of redox mediators such as riboflavin led to dramatic acceleration of the anaerobic biodecolourisation process. The azo dye reduction products were found to be sulphanilic acid and 4-aminoresorcinol for acid orange 6; sulphanilic acid and 1-amino-2-naphthol for acid orange 7; N,N-dimethyl-1,4-phenylenediamine and sulphanilic acid for methyl orange; and N,N-dimethyl-1,4-phenylenediamine and anthranilic acid for methyl red. Anaerobic toxicity assays showed that the azo dyes were more toxic than their breakdown products (aromatic amines), except 1-amino-2-naphthol. In the presence of activated sludge, only anthranilic acid was completely mineralised while sulphanilic acid was persistent. 4-aminoresorcinol, 1-amino-2-naphthol and N,N-dimethyl-1,4-phenylenediamine underwent autooxidation in aerobic conditions yielding coloured polymeric products. On the contrary, in the presence of granular methanogenic sludge, 4-aminoresorcinol, 1-amino-2-naphthol and anthranilic acid were quantitatively methanised, sulphanilic acid was partially (70%) mineralised while N,N-dimethyl-1,4-phenylenediamine was only demethylated producing 1,4-phenylenediamine as an end product.