Tolerance and Bioaccumulation of Arsenate by Aspergillus Oryzae TLWK-09 Isolated from Arsenic-Contaminated Soils

Eleven indigenous arsenic-tolerant fungi were isolated from arsenic-contaminated mine tailing and identified by molecular biology methods. Among them, Aspergillus oryzae (denoted as A. oryzae TLWK-09) had high tolerance and bioaccumulation of As(V). The maximum tolerance to As(V) concentration of A. oryzae TLWK-09 reached 5000 mg/L. As(V) bioaccumulation on A. oryzae TLWK-09 in the aqueous system was investigated under different environmental conditions such as mycelia dosage, contact time, pH, and ionic strength. Bioaccumulation data of As(V) were fitted to Langmuir model, and the maximum uptake capacity of A. oryzae TLWK-09 for As(V) was 54.12 mg/g at 301 K. The morphological structures of mycelia changed obviously under As(V) stress by scanning electron microscope (SEM) and transmission electron microscope (TEM) analysis. The analysis of Fourier transform infrared spectroscopy (FTIR) indicated the presence of carboxyl, hydroxyl, and amino groups on the fungal mycelia, which showed that these groups accounted for As(V) bioaccumulation. These results suggested that A. oryzae TLWK-09 could be an efficient and promising bioremediation material for As(V) pollution.