Bio-remediation of acephate–Pb(II) compound contaminants by Bacillus subtilis FZUL-33

Removal of Pb2 + and biodegradation of organophosphorus have been both widely investigated respectively. However, bio-remediation of both Pb2 + and organophosphorus still remains largely unexplored. Bacillus subtilis FZUL-33, which was isolated from the sediment of a lake, possesses the capability for both biomineralization of Pb2 + and biodegradation of acephate. In the present study, both Pb2 + and acephate were simultaneously removed via biodegradation and biomineralization in aqueous solutions. Batch experiments were conducted to study the influence of pH, interaction time and Pb2 + concentration on the process of removal of Pb2 +. At the temperature of 25°C, the maximum removal of Pb2 + by B.subtilis FZUL-33 was 381.31 ± 11.46 mg/g under the conditions of pH 5.5, initial Pb2 + concentration of 1300 mg/L, and contact time of 10 min. Batch experiments were conducted to study the influence of acephate on removal of Pb2 + and the influence of Pb2 + on biodegradation of acephate by B.subtilis FZUL-33. In the mixed system of acephate–Pb2 +, the results show that biodegradation of acephate by B.subtilis FZUL-33 released PO43 +, which promotes mineralization of Pb2 +. The process of biodegradation of acephate was affected slightly when the concentration of Pb2 + was below 100 mg/L. Based on the results, it can be inferred that the B.subtilis FZUL-33 plays a significant role in bio-remediation of organophosphorus-heavy metal compound contamination.

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