Non-sterilized fermentative production of acetoin with 2,3-butanediol as a main byproduct from maize hydrolysate by a newly isolated thermophilic Bacillus strain

Zijun Xiao, Rulin Gu, Xiaoyuan Hou, Jing yi Zhao, Hu Zhu, Jian Lu

    Research output: Contribution to journalArticlepeer-review

    Abstract

    BACKGROUND: Acetoin is an important biorefinery platform chemical with many industrial uses. It is mainly produced by chemical synthesis or mesophilic fermentation with high costs. RESULTS: A thermophilic Bacillus strain was isolated to efficiently produce acetoin from maize hydrolysate at 50°C. The fermentation medium was statistically optimized by Plackett-Burman design. Operational conditions were then optimized using a 4.2 L fermenter conducted at 50°C without sterilization. Oxygen enriched air (65% oxygen) accelerated substrate consumption but did not increase product titer. In comparison with 600 rpm, agitation speed controlled at 400 rpm yielded less acetoin but more 2,3-butanediol in the final products. A two-stage pH control strategy (pH first at 6.6-7.1 then at 7.7-8.0) was applied to further increase the yield of acetoin. Finally, 50.8 g L-1 of acetoin and 32.1 g L-1 of 2,3-butanediol were obtained from 251 g L-1 of degermed maize flour (dry weight). The conversion yield from sugar to the 4-carbon compounds (acetoin and 2,3-butanediol) was 94.4% of the theoretical value. CONCLUSION: This is the first report of non-sterilized fermentative production of acetoin. Using degermed maize hydrolysate as the main feedstock, this work sets a new titer record of acetoin fermentation among known thermophilic producing systems. copy; 2017 Society of Chemical Industry.

    Original languageEnglish
    JournalJournal of Chemical Technology and Biotechnology
    Volume92
    Issue number11
    Early online date11 May 2017
    DOIs
    Publication statusPublished - Nov 2017

    Keywords

    • 2,3-butanediol
    • Acetoin
    • Bacillus
    • Cost-effective
    • Maize hydrolysate
    • Non-sterilized thermophilic fermentation

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