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World journal of microbiology & biotechnology
Mar 28, 2025;41 (4): 117.

Microbial synthesis of enantiopure (S)-2-methylbutanoic acid via L-isoleucine catabolism in Bacillus spizizenii.

Jing-Yi Zhao, Fan Gao, Mengru Wu, Yang Li, Yong Chen, Zijun Xiao
Author Information
  1. Jing-Yi Zhao: Department of Biology and Energy Chemical Engineering, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), 66 Changjiang West Road, Huangdao District, Qingdao, 266580, China.
  2. Fan Gao: Department of Biology and Energy Chemical Engineering, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), 66 Changjiang West Road, Huangdao District, Qingdao, 266580, China.
  3. Mengru Wu: Department of Biology and Energy Chemical Engineering, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), 66 Changjiang West Road, Huangdao District, Qingdao, 266580, China.
  4. Yang Li: Department of Biology and Energy Chemical Engineering, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), 66 Changjiang West Road, Huangdao District, Qingdao, 266580, China.
  5. Yong Chen: Department of Biology and Energy Chemical Engineering, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), 66 Changjiang West Road, Huangdao District, Qingdao, 266580, China.
  6. Zijun Xiao: Department of Biology and Energy Chemical Engineering, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), 66 Changjiang West Road, Huangdao District, Qingdao, 266580, China. zjxiao@upc.edu.cn.
PMID: 40148725 DOI: 10.1007/s11274-025-04324-8

Abstract

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.

Keywords

Bacillus spizizenii (S)-2-methylbutanoic acid Chiral synthesis L-isoleucine catabolism

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Grants

  1. 31771946/National Natural Science Foundation of China

MeSH Term

Bacillus
Isoleucine
Stereoisomerism
Soil Microbiology
Glucose
Butyrates
Secondary Metabolism

Chemicals

Isoleucine
Glucose
Butyrates
Journal Article

Word Cloud

Created with Highcharts 10.0.0S-2-MBAL-isoleucine-2-methylbutanoicacidsynthesisBacillusspizizeniiATCC6633catabolismpurityprocessproductionvia32%glucoseEnantiopure[-2-MBA]high-valuechiralcompoundapplicationsfragrancespharmaceuticalsagrochemicalsHoweverconventionalchemicallacksstereoselectivityexistingbiosyntheticmethodssufferlowyieldreportnovelmicrobialusingefficienttargetedscreeningrhizosphericsoilisolatesBacillaceaestrainsdemonstratedsuperiorperformanceproducing367 g/L99enantiomericexcesseeoptimizedconditions45 °C8%inoculation5 g/L8 g/L5892%conversionefficiencyachievedsimplifiedpurificationrecovered6390%product97Mechanisticstudiessuggesteddepletiontriggeredaccumulationaligningstarvation-inducedsecondarymetabolismcost-effectiveeco-friendlyapproacheliminatesracemicseparationstepsharshreagentspositioningpromisingbiocatalystsustainableMicrobialenantiopureChiral

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