Biodegradation of ZEN by Bacillus mojavensis L-4: Analysis of Degradation Conditions, Products, Degrading Enzymes, and Whole-Genome Sequencing, and Its Application in Semi-Solid-State Fermentation of Contaminated Cornmeal

Jiagao Chang ¹ Wenxuan Dong ¹ Shansong Gao ¹ Lele Hou ¹ Jihong Dong ¹ Huiling Qiu ^2* Fu Chen ^1*

• ¹ Qingdao Agricultural University, Qingdao, China
• ² Haidu College, Qingdao Agricultural University, Laiyang, Shandong, China

AbstractZearalenone (ZEN), a naturally occurring estrogenic mycotoxin prevalent in cereals and animal feed, poses significant challenge to livestock industry owing to its detrimental effects on animal reproduction. In this study, we isolated Bacillus mojavensis L-4 from the cecal content of laying hens, which demonstrated exceptional ZEN-degrading efficiency. Under optimized conditions (pH 7.0, 37 °C), L-4 completely degraded 0.5–1.0 µg/mL ZEN into less toxic 15-OH-ZEN within 24 h. Importantly, L-4 achieved a 49.41% degradation rate for ZEN in cornmeal. Whole-genome sequencing of L-4 revealed the presence of ZEN-degrading genes and enzymes. In particular, efeB 3668, a peroxidase-like enzyme with high homology (95.91%) to BsDyP from Bacillus subtilis, played a key role in ZEN detoxification primarily through hydrogen bonding and hydrophobic interactions. Thus, the rapid and effective degradation of ZEN by B. mojavensis L-4, coupled with its adaptability to diverse environments, underscores its potential application in safeguarding animal health and mitigating environmental pollution.