Remediation of Inorganic Mercury From Spent Fluorescent Lamps Using Heterotrophic Bacterial Strains Isolated From Domestic Wastewater

Abstract

ABSTRACT Inorganic mercury from spent fluorescent lamps is classified as hazardous waste and has become a severe concern for the environment. This study aimed to survey the effect of indigenous heterotrophic bacteria from domestic wastewater on the remediation of inorganic mercury. In this study, the mercury from phosphor power was leached and then detoxified using bacterial strains isolated from domestic wastewater. Nitric and hydrochloric acid solutions were applied for mercury leaching. Twenty‐eight bacterial strains were isolated from domestic wastewater on Reasoner's 2A agar. Then, to check the bacterial mercury resistance, these strains were sub‐cultured on a Luria‐Bertani medium amended with mercury chloride. 16S rRNA gene sequencing was used to determine the genus and species of mercury‐reducing bacteria. This method was performed by the polymerase chain reaction (PCR) amplification of 16S rRNA, followed by sequencing. Bacterial strains demonstrating the remediation capacity of mercury were Acinetobacter junii, Aeromonas cariae, Pseudomonas alcaliphila, Pseudomonas marginalis, Aeromonas sanarellii, Klebsiella singaporensis , and Pseudomonas simiae . These strains showed bio‐uptake efficiency within the range of 67.9% to 92.2%. The lowest and highest rates of mercury remediation were related to P. simiae (67.9%) and P. marginalis (92.24%), respectively. The results show that 18 of these 28 bacterial strains displayed resistance to mercury. To determine the bio‐uptake capacity, the bacteria isolated from wastewater were exposed to the mercury leached from the fluorescent lamps, and mercury content was measured by atomic absorption spectrophotometry. The seven bacteria isolated from wastewater reduced the mercury concentration to less than 5 μg/L. The results of this study revealed that sewage heterotrophic bacteria can be used as an efficient and low‐cost method for mercury bioremediation in discarded fluorescent lamps.

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Identifiers

DOI

10.1002/rem.70011

Journal

Remediation Journal

Year

2025