Degradation of aflatoxin B1 by Bacillus velezensis 906 postbiotics: potential mechanism and safety evaluation

Optimized postbiotics achieved 88.5% AFB 1 degradation with Cu 2+ or Fe 2+ . • Postbiotics attack furan and lactone rings of AFB1 to yield C 17 H 12 O 5 and C 16 H 12 O 5 . • Postbiotics reduced AFB 1 in peanut meal to below safety standard. • Postbiotics alleviated hepatic injury and inflammation in mice. • Postbiotics promoted the colonization of beneficial gut microbials. Probiotics and postbiotics offer a promising approach to decontaminate widely occurring aflatoxin B 1 (AFB 1 ). This study identified and optimized the postbiotics from Bacillus velezensis 906, systematically exploring the degradation products and pathways and evaluating the degradation efficacy and in vivo safety. The optimized postbiotics degraded 77.6% of AFB 1 in vitro , which increased to 88.5% with Cu 2+ supplementation. The degradation process involves lactone ring cleavage and furan ring modification to yield C 17 H 12 O 5 and C 16 H 12 O 5 . In moldy peanut meal, treatment merely with postbiotics and probiotics inhibited fungal growth and reduced AFB 1 from 100.86 μg/kg to 37.54 μg/kg and 45.81 μg/kg, while preserving nutritional quality. Oral gavage of moldy peanut meal treated with postbiotics significantly reduced serum alanine aminotransferase (ALT) by 29%, malondialdehyde (MDA) by 43.60% and interleukin-1β (IL-1β) by 59.8%, and normalized liver pathology and the gut microbiota ratio. In summary, B. velezensis 906 can efficiently degrade AFB 1 , ensuring the safety of moldy peanut meal for consumption while preserving its quality and nutritional value, providing an effective and safe strategy for the mycotoxin bioremediation in food and feed matrices. Download: Download high-res image (440KB) Download: Download full-size image