Isolation and Characterization of the Zearalenone-Degrading Strain, Bacillus spizizenii B73, Inspired by Esterase Activity

Zearalenone (ZEN) is a widespread mycotoxin found in grain and feed, presenting a serious threat to animal and human health. This study investigated the ability of the novel strain B73, isolated from petroleum-contaminated soil, to detoxify ZEN. B73 was identified asBacillus spizizeniithrough physiological and biochemical tests, and further confirmed based on the 16S rRNA gene sequence and the complete genome sequence.B. spizizeniiB73 was capable of degrading up to 99.3% of ZEN at a concentration of 10 μg/mL in a minimal medium (pH = 7.0) within 8 h at 37 °C via HPLC-UV. In addition,B. spizizeniiB73 was used to treat ZEN-contaminated wheat bran, dried distillers grains (DDGS), and corn meal, whereby the respective degradation rates reached 96.32%, 98.73%, and 80.31% after 36 h of treatment. HPLC-Q-Exactive-MS/MS analysis revealed one of the degradation products to have the formula C17H24O4.B. spizizeniiB73 is a novel strain isolated from petroleum-contaminated soil, and the extracellular enzymes secreted by this strain show a remarkable ability to degrade ZEN.Keywords:zearalenone;Bacillus spizizenii;detoxification;cell extract;enzymeKey Contribution:Our study demonstrates thatBacillus spizizeniiB73 is capable of optimally degrading ZEN at 37 °C, pH 7.0, and with a 4% inoculation amount. After 36 h of degradation, ZEN degradation rates in wheat bran, corn meal, and DDGS were found to be 96.32%, 98.73%, and 80.31%, respectively, when the medium contained 50% grain content.