Arsenite oxidation in batch reactors with alginate-immobilized ULPAs1 strain

Arsenic is one of the major groundwater contaminants worldwide. It was previously demonstrated that the β-proteobacterium Cenibacterium arsenoxidans has an efficient As[III] oxidation ability. The present study was conducted to evaluate the performance of alginate-immobilized ULPAs1 in the oxidation of As[III] to As[V] in batch reactors. A two-level full factorial experimental design was applied to investigate the influence of main parameters involved in the oxidation process, i.e., pH (7–8), temperature (4°C–25°C), kind of nutrient media (2%–20% sauerkraut brine), and arsenic concentration (10–100 mg/L). One hundred milligram per liter of As[III] was fully oxidized by calcium-alginate immobilized cells in 1 h. It was found that the temperature as well as the kind of nutrient media used were significant parameters at a 95% confidence interval whereas only temperature was a significant parameter at a 99% confidence interval. The immobilization of the As[III] oxidizing strain in alginate beads offers a promising way to implement new treatment processes in the remediation of arsenic contaminated waters. © 2005 Wiley Periodicals, Inc.