Characterization of Arsenite-Oxidizing Bacteria Isolated from Arsenic-Rich Sediments, Atacama Desert, Chile

Abstract

Arsenic (As), a semimetal toxic for humans, is commonly associated with serious health problems. The most common form of massive and chronic exposure to As is through consumption of contaminated drinking water. This study aimed to isolate an As resistant bacterial strain to characterize its ability to oxidize As (III) when immobilized in an activated carbon batch bioreactor and to evaluate its potential to be used in biological treatments to remediate As contaminated waters. The diversity of bacterial communities from sediments of the As-rich Camarones River, Atacama Desert, Chile, was evaluated by Illumina sequencing. Dominant taxonomic groups (>1%) isolated were affiliated with Proteobacteria and Firmicutes. A high As-resistant bacterium was selected (Pseudomonas migulae VC-19 strain) and the presence of aio gene in it was investigated. Arsenite detoxification activity by this bacterial strain was determined by HPLC/HG/AAS. Particularly when immobilized on activated carbon, P. migulae VC-19 showed high rates of As(III) conversion (100% oxidized after 36 h of incubation). To the best of our knowledge, this is the first report of a P. migulae arsenite oxidizing strain that is promising for biotechnological application in the treatment of arsenic contaminated waters.

Winogradsky Bioelectrochemical System as a Novel Strategy to Enrich Electrochemically Active Microorganisms from Arsenic-Rich Sediments

“…The sediment bacterial communities were dominated mainly by the phyla Chlorobi, Chloroflexi, and Nitrospirae (Figure 4). These phyla have been reported as groups present in As-rich environments in the same region of Chile [37][38][39] as in other arsenic-rich environments, such as rice soil in India [40] and China [41,42]. Moreover, previous studies have demonstrated that genes related to As redox reactions are present in diverse phylogenetic groups of prokaryotes, including members of Proteobacteria, Chlorobi, Chloroflexi, and Nitrospirae [43,44].…”

Arsenic Contamination of Groundwater Is Determined by Complex Interactions between Various Chemical and Biological Processes

“…Arsenate is a structural analog of phosphate that competes with phosphate in many biochemical reactions [ 8 , 57 , 60 , 63 ]. The bonds that arsenate forms with phosphate and carboxyl groups are unstable and hydrolyze spontaneously: in oxidative phosphorylation, the analogue of the mitochondrial ATP synthesis reaction, i.e., ADP + arsenate + 4H + out → ADP-arsenate + 4H + in , is followed by the rapid hydrolysis of the high-energy bond of the ADP-arsenate (ADP-arsenate → ADP + arsenate).…”

On the Scarce Occurrence of Arsenic in Vineyard Soils of Castilla La Mancha: Between the Null Tolerance of Vine Plants and Clean Vineyards

“…In addition, the bacteria and fungi surrounding plant roots can promote plants' uptake of As, and also of heavy metals, by changing their activity. It is known that some bacteria can reduce As, while others can oxidize As [56].…”