Degradation of β-HCH by Enterobacter sp. CS01: Characteristics, mechanism and application in soil remediation

Abstract

β-Hexachlorocyclohexane (β-HCH) is a persistent organochlorine pesticide that poses a significant threat to the ecological environment, necessitating the urgent development of effective degradation methods. Microbial degradation has demonstrated substantial potential among various bioremediation techniques due to its environmentally friendly and economical characteristics. This study evaluates the degradation capability of Enterobacter sp. CS01 on β-HCH, its physiological responses, and its potential application in soil remediation. Under optimal conditions (pH 7, 30°C), 51 % of β-HCH was effectively removed. Metabolomics and antioxidant enzyme activity analyses revealed that CS01 defends against oxidative damage by modulating the activities of superoxide dismutase (SOD) and catalase (CAT), involving butyrate, alanine, aspartate, and glutamate metabolism, as well as the pentose phosphate pathway. CS01 converts β-HCH into less toxic intermediates through dichloride elimination, dehalogenation of hydrogen, and hydrolysis reactions. Soil experiments indicated that soil enzyme activities (S-POD, S-DHA, S-PPO) are closely related to the degradation of β-HCH, with the order of carbon source utilization being esters, amino acids, and sugars. This study provides new insights into the microbial degradation mechanisms of organochlorine pesticides and aids in the development of more efficient and environmentally friendly degradation technologies.