Characterization and application potential in soil remediation of two aerobic arsenate-reducing bacteria isolated from arsenic-contaminated soils.

Abstract

Mobilization and release of arsenic (As) from the soil matrix is essential to promote the in situ remediation efficiency of As-contaminated soil. In the current study, two aerobic As(V)-reducing strains Leclercia sp. SMR8 and Klebsiella sp. SMR14 were isolated from As-contaminated soils. The As(V) reduction capacity was mediated by the arsC gene which was successfully amplified from both strains. The bacterial growth characteristics were evaluated, and both strains demonstrated good environmental adaptability with high As(V) tolerance, wide growth temperature range, and utilization of various carbon substrates. Except for bacterial growth and regulation of ars genes, initial As(V) concentration was confirmed as the dominant factor impacting the As(V) reduction rate by the strains. The reduced As(V) proportion decreased from 95 to 70% with increasing the initial As(V) concentration from 100 to 600 mg/L. The results of soil extraction experiments showed that the addition of the strains promoted As extraction efficiency from contaminated soil, and the process was significantly influenced by the added carbon substrates. SMR14 using glucose as a carbon source exhibited excellent extraction efficiency, indicating application potential in soil remediation.