Mechanisms and applications of aflatoxin degradation by engineered <i>Lactobacillus plantarum</i> in food systems

Abstract Aflatoxin B 1 (AFB 1 ) is a highly toxic mycotoxin that contaminates grain and oil foods. Its strong carcinogenicity poses a serious threat to global food safety. Existing biological detoxification methods have limitations such as poor enzyme stability or insufficient antimicrobial efficacy, highlighting the urgent need for synergistic solutions with both efficient degradation and mould inhibition capabilities. This study aims to construct an engineered Lactobacillus plantarum strain that secretes Spore coat protein A laccase (CotA laccase) and systematically evaluate its AFB 1 degradation ability and industrial application potential. The engineered strain Lp‐CotA was successfully constructed using genetic engineering technology. Mechanistic studies revealed that the CotA enzyme breaks the lactone ring structure of AFB 1 , converting it into low‐toxicity products AFQ 1 and epi‐AFQ 1 , thereby reducing cytotoxicity. Application experiments showed that the engineered strain achieved over 85% AFB 1 degradation within 72 h. In flour, it exhibited preventive and repair effects against AFB 1 , effectively inhibited mould growth, and maximally preserved nutritional components. In apple preservation, the engineered strain controlled the decay rate to 10% with an AFB 1 degradation rate of 85.9%. This research provides an efficient and safe solution for the biological control of AFB 1 in grains, fruits, and vegetables, with important industrial application prospects.