Bio-adsorption and Bio-transformation of Arsenic by Acidithiobacillus ferrooxidans BY3.

ABSTRACT

Arsenic, a toxic element in the environment, has seriously threatened the health of hundreds of millions of people in the world. Meanwhile, microorganisms play an important role in the adsorption and bio-transformation of arsenic. Here, we compared the biological characteristics of Acidithiobacillus ferrooxidans BY3 in different media systems, such as arsenic bio-adsorption and bio-transformation capacities. We show that arsenic stress significantly affected the pH and Eh of the culture systems, as well as the oxidation rates of Fe2+ and bacteria numbers. Furthermore, arsenic influenced bacterial structure and composition of the cell membrane, caused volume decreased and changed the vibration conditions of characteristic peaks of surface groups (-CH2, -NH, and -OH) on cell membranes. In addition, At.f-BY3 shows high bio-adsorption abilities and certain bio-transformation abilities for iAsIII. Bio-adsorption and conversion efficiency was also shown to be significantly affected by Fe2+ concentrations in the reaction systems. Statistic analysis revealed 10.07-fold increase of the transformation ability of iAsIII into iAsV in the 9 K growth media containing 1600 mg/L NaAsO2 compared with that in the 1 K growth media. Our findings contribute to understand the applications and microbiological mechanisms of Acidithiobacillus ferrooxidans in arsenic pollution. Graphical Abstract Bio-adsorption and bio-transformation are used as a biological method of heavy metals pollution, such as Cu2+, Ni2+, Pb2+, Cr2+, Zn2+, Cd2+, As3+ and As5+ in acid mine water. The aim of this investigation was to assess the performance of arsenite (iAsIII) to adsorption and transformation by Acidithiobacillus ferrooxidans BY3, and application of Acidithiobacillus ferrooxidans BY3 on the aspect of arsenic pollution has great potential of exploration.