A novel carboxylesterase Est3617 from a food-fermentation bacterium for rapid remediation of β-cyfluthrin in environment and food.

Abstract

The ubiquitous contamination of pyrethroid insecticides poses significant threats to environmental safety and human health. In this study, Aneurinibacillus aneurinilyticus D-21, isolated from traditional fermented food Pixian broad bean paste, was identified as an efficient degrader of β-cyfluthrin (β-CYF). Transcriptomic analysis under β-CYF stress uncovered a key carboxylesterase gene est3617, which was cloned and expressed in Escherichia coli. The purified enzyme Est3617, containing a canonical catalytic triad (Ser97-Asp193-His223), exhibited optimal activity at 45 °C and pH 9.0, along with broad substrate specificity and notable stability under varied temperature and pH conditions. Importantly, Est3617 demonstrated high efficacy in degrading β-CYF residues across various environmental matrices (water, soil and sediments). Within 24 h of treatment, over 75 % of β-CYF was degraded and its half-life was significantly reduced to 5.32-8.26 h. Moreover, when employed as a cleaning agent for fruits and vegetables, Est3617 also exhibited considerable potential for removing β-CYF residues, achieving degradation rates of 67.02-81.35 % within 60 min among different vegetable types. These results support Est3617 as a promising and potentially safe biocatalyst, enabling a practical "from environment to food" enzymatic strategy to mitigate pyrethroid contamination.