A Bacillus subtilis Strain ZJ20 with AFB1 Detoxification Ability: A Comprehensive Analysis

SIMPLE SUMMARY: AFB(1) is the most toxic mycotoxin known and is considered a class of carcinogens with serious damaging effects on various tissues and organs, especially the liver. In this study, we screened a Bacillus subtilis ZJ20 that effectively degraded AFB(1) (84.23% degradation rate) and sequenced and analyzed its complete genome. The general traits of Bacillus subtilis ZJ20 and its genome were outlined, and further genetic analyses showed that the strain had strong enzyme content, metabolic activity, and antioxidant capacity. Potential antibacterial, antifungal, and antiviral capacities of ZJ20 were hypothesized by metabolic prediction. In addition, genes encoding AFB(1)-degrading enzymes, including chitinase, laccase, lactonase, and manganese peroxidase, were identified in the whole genome of ZJ20, demonstrating that ZJ20 degrades AFB(1) through multiple enzymes. ABSTRACT: As a class I carcinogen, aflatoxin can cause serious damage to various tissues and organs through oxidative stress injuries. The liver, as the target organ of AFB(1), is the most seriously damaged. Biological methods are commonly used to degrade AFB(1). In our study, the aflatoxin B(1)-degrading strain ZJ20 was screened from AFB(1)-contaminated feed and soil, and the degradation of AFB(1) by ZJ20 was investigated. The whole genome of strain ZJ20 was analyzed, revealing the genomic complexity of strain ZJ20. The 16S rRNA analysis of strain ZJ20 showed 100% identity to Bacillus subtilis IAM 12118. Through whole gene functional annotation, it was determined that ZJ20 has high antioxidant activity and enzymatic activity; more than 100 CAZymes and 11 gene clusters are involved in the production of secondary metabolites with antimicrobial properties. In addition, B. subtilis ZJ20 was predicted to contain a cluster of genes encoding AFB(1)-degrading enzymes, including chitinase, laccase, lactonase, and manganese oxidase. The comprehensive analysis of B. subtilis provides a theoretical basis for the subsequent development of the biological functions of ZJ20 and the combinatorial enzyme degradation of AFB(1).