Enantiopure ( S )-2-methylbutanoic acid [( S )-2-MBA] is a high-value chiral compound with applications in fragrances, pharmaceuticals, and agrochemicals. However, conventional chemical synthesis lacks stereoselectivity, while existing biosynthetic methods suffer from low yield and purity. Here, we report a novel microbial process using Bacillus spizizenii ATCC 6633 for efficient ( S )-2-MBA production via L-isoleucine catabolism. Through targeted screening of rhizospheric soil isolates and Bacillaceae strains, ATCC 6633 demonstrated superior performance, producing 3.67 g/L ( S )-2-MBA with 99.32% enantiomeric excess ( ee ) under optimized conditions (45 °C, 8% inoculation, 5 g/L glucose, and 8 g/L L-isoleucine). A 58.92% conversion efficiency was achieved, and a simplified purification process recovered 63.90% product with 97.32% purity. Mechanistic studies suggested glucose depletion triggered ( S )-2-MBA accumulation, aligning with starvation-induced secondary metabolism. This cost-effective, eco-friendly approach eliminates racemic separation steps and harsh reagents, positioning ATCC 6633 as a promising biocatalyst for sustainable ( S )-2-MBA production.
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.
危险品化学品经营许可证（带存储）