Bioremediation of β-cypermethrin and 3-phenoxybenzaldehyde contaminated soils using Streptomyces aureus HP-S-01

Using laboratory and field experiments, the ability of Streptomyces aureus HP-S-01 to eliminate beta-cypermethrin (beta-CP) and its metabolite 3-phenoxybenzaldehyde (3-PBA) in soils was investigated. In the laboratory, 80.5% and 73.1% of the initial dose of beta-CP and 3-PBA (50 mg kg(-1)) was removed in sterilized soils within 10 days, respectively, while in the same period, disappearance rate of beta-CP and 3-PBA in non-sterilized soils was higher and reached 87.8% and 79.3%, respectively. Furthermore, the disappearance process followed the first-order kinetics and the half-life (T (1/2)) for beta-CP and 3-PBA reduced by 20.3-52.9 and 133.7-186.8 days, respectively, as compared to the controls. The addition of sucrose to the soils enhanced the ability of strain HP-S-01 to eliminate beta-CP and 3-PBA. Similar results were observed in the field experiments. The introduced strain HP-S-01 quickly adapted to the environment and rapidly removed beta-CP and 3-PBA without any lag phases in the field experiments. Compared with the controls, 47.9% and 67.0% of applied dose of beta-CP and 3-PBA was removed from the soils without extra carbon sources and 52.5% and 73.3% of beta-CP and 3-PBA was eliminated in soils supplemented with sucrose within 10 days, respectively. Analysis of beta-CP degradation products in soil indicated that the tested strain transform beta-CP to 3-PBA and alpha-hydroxy-3-phenoxy-benzeneacetonitrile. However, both intermediates were transient and they disappeared after 10 days. Therefore, the selected actinomyces strain HP-S-01 is suitable for the efficient and rapid bioremediation of beta-CP contaminated soils.