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Background: Arsenic contamination in the ground water of rural India is a recurrent problem and decontamination is mostly based on the chemical or physical treatments until now. Microbial bioremediation is eco-friendly, cheap, time-efficient and does not produce any toxic by-products. Result: In the present study, a high arsenic tolerant bacteria Brevundimonas aurantiaca PFAB1 was isolated from Panifala hot spring located in West Bengal, India. Previously Panifala was also reported to be an arsenic-rich hot spring. B. aurantiaca PFAB1 exhibited both positive arsenic reductase and arsenite oxidase activity. It was tolerant to arsenite up to 90 mM and arsenate up to 310 mM. Electron microscopy has proved significant changes in cellular micromorphology and stalk appearance under the presence of arsenic in growth medium. Bioaccumulation of arsenic in As (III) treated cells were 0.01% of the total cell weight, while 0.43% in case of As (V) treatment. Conclusions: All experimental lines of evidence prove the uptake/accumulation of arsenic within the bacterial cell. All these features will help in the exploitation of B. aurantiaca PFAB1 as a potent biological weapon to fight arsenic toxicity in the near future.How to cite: Banerjee A, Sarkar S, Gorai S, et al. High arsenic tolerance in Brevundimonas aurantiaca PFAB1 from an arsenic-rich Indian hot spring. Electron J Biotechnol 2021:52. https://doi.org/10.1016/j.ejbt.2021.05.006

Background: Arsenic contamination in the ground water of rural India is a recurrent problem and decontamination is mostly based on the chemical or physical treatments until now. Microbial bioremediation is eco-friendly, cheap, time-efficient and does not produce any toxic by-products. Result: In the present study, a high arsenic tolerant bacteria Brevundimonas aurantiaca PFAB1 was isolated from Panifala hot spring located in West Bengal, India. Previously Panifala was also reported to be an arsenic-rich hot spring. B. aurantiaca PFAB1 exhibited both positive arsenic reductase and arsenite oxidase activity. It was tolerant to arsenite up to 90 mM and arsenate up to 310 mM. Electron microscopy has proved significant changes in cellular micromorphology and stalk appearance under the presence of arsenic in growth medium. Bioaccumulation of arsenic in As (III) treated cells were 0.01% of the total cell weight, while 0.43% in case of As (V) treatment. Conclusions: All experimental lines of evidence prove the uptake/accumulation of arsenic within the bacterial cell. All these features will help in the exploitation of B. aurantiaca PFAB1 as a potent biological weapon to fight arsenic toxicity in the near future. [ABSTRACT FROM AUTHOR]

Bacterial isolates from water and sediment samples from freshwater, estuarine and marine regions were tested for their growth in the presence of different concentrations of arsenic. Despite the generation times being longer in case of all bacterial isolates tested in nutrient broth with 200 ppm Arsenite (As3+), many of them were able to attain log phase and substantial growth variously between 36 and 96 h. The isolates tolerating ⩾200 ppm arsenic (As) were found to belong to Enterobacteriaceae, Pseudomonas, Corynebaterium, Xanthomonas, Acinetobacter, Flavimonas and Micrococcus. Some of these environmental strains tolerant to 1,000 ppm arsenic were tested to realize their potential to detoxify arsenic. The rate of As biotransformation was faster by many of these strains. The percent of arsenite biotransformed/ removed from the growth medium was the highest by a strain of Enterobacteriaceae (as much as 92% of the As in the growth medium by 120 h) followed by that of Corynebaterium and Acinetobacter strains. From these observations it is clear that many environmental strains are capable of quite rapid biotransformation of As. Contamination of drinking water by toxic metalloid arsenic affects thousands of people worldwide. Many environmental isolates of bacteria which detoxify this metalloid would serve beneficial in the depuration processes. We suggest that only such strains capable of high tolerance to toxic arsenite, would biotransform As in polluted estuarine environments and would prove useful in As bioremediation applications. [ABSTRACT FROM AUTHOR]