Comparison of arsenate reduction and release by three As(V)-reducing bacteria isolated from arsenic-contaminated soil of Inner Mongolia, China

Arsenic (As) contamination has become a worldwide environmental problem: arsenite (As(III)) especially has posed a major threat to human health. Here, we report the first three isolates of anaerobic As(V)reducing bacterial strains (strains JQ DJ-3 and DJ-4) from a soil sample containing 48.7% of total As in the form of As(III) collected in Chifeng, Inner Mongolia, China. Strains JQ, DJ-3 and DJ-4 were phylogenetically closely related to Bacillus, Desuffitobacterium and Exiguobacterium, respectively. Among these strains, JQ and DJ-3 have the arsC gene, DJ-4 possesses the arrA gene. The three strains could all resist and reduce high concentrations of As(V) under anoxic conditions. The order of resistance to As(V) was DJ 3 > JQ > DJ-4. Strain DJ-3 not only possesses the strongest resistance to As(V) but could also reduce 53% of the As(V) to As(III) in the treatment of 60 mM As(V) in 5 d. All three strains could release As from goethite; strain DJ-4 has the highest ability to promote the release of As (90.5%) from goethite. These results suggested that strains JQ DJ-3 and DJ-4 may play an important role in the mobilization and transformation of As in soil. (C) 2016 Elsevier Ltd. All rights reserved.