Isolation And Identification Of Arsenic-resistant Bacteria And Their Abilities To Reduce As(Ⅴ) Or Oxidizie As(Ⅲ)

Microbial remediation has been recognized as an economically efficient remediation method without secondary pollution and have been concerned by many researchers. In recent years, microbial remediation of arsenic has been conducted and obtained some achievement. However, some relative works are still remained indoor experimently while some problems of technique are unsolved. Hence, on the basis of the current studies, it is important to study the interaction between arsenic and microorganism, which will provide sufficient theoretical support and biomaterial for the application of technique of arsenic microbial remediation.In this study,we isolated and identificated that highly effective arsenic-resistant bacterial strains from arsenic-contaminated soils in ShiMeng of China and explore their capable of reducing arsenate to arsenite under laboratory conditions,The principal findings were obtained as follows:1. Isolation of As resistant bacterial strains were carried out with serially diluted plating.The results indicated that 28 As-resistant bacterial strains were isolated from eight soil samples,and better colony growth of 2-2,4-3 and 8-5 were presented when the As stress concentration was 2000mg. It indicate that screening of three bacterial strains have high-resistance to arsenic.2. The morphological and 16SrDNA-based molecular biological identification of three bacterial strins were conducted.The results showed that the colony morphology,spore structure of 2-2,4-3 and 8-5 were respectively similar to those of Pseudomonas taiwanensis、Pseudomonas monteilii and Pseudomonas sp. and with 100% of the similarity of all.Online sequences comparision to GenBank obtained accession number as follow:KP313734,KP313735, and KP313736.3. The abilities of As oxidation and reduction were evaluated under laboratory conditions.The results indicated that three bacterial strains have no As(III)-oxidating ability but higher As(V)-reducing activity in batch tests. That Pseudomonas taiwanensis and Pseudomonas monteilii completely reducing 10mg·L-1 of As(V) to As(III) with 6h under laborary conditions. In addition, the results showed that three bacterial strains have biological adsorption ability of As(III) and As (V).