Researchers Engineer Bacillus licheniformis for the Production of Liquid Fuel Additive

2,3-Butanediol (2,3-BD) can be used as a liquid fuel additive to replace petroleum oil, and is important in the pharmaceutical and plastic industries. Microbial production of 2,3-BD by Bacillus licheniformis presents potential advantages, but previous attempts have resulted in the production of a mix of D-2,3-BD and meso-2,3-BD isomers.

Scientists from Hubei University and Huazhong Agricultural University in China wanted to develop a strain of B. licheniformis that produces high titers of the pure meso-2,3-BD isomer. Researchers then deleted the gdh gene, a catalyst for D-2,3-BD biosynthesis, from the wild-type strain WX-02. The acoR gene, involved in acetoin degradation, was also deleted to divert acetoin, a precursor, towards meso-2,3-BD.

The double-deletion mutant produced 28.2 g/L of meso-2,3-BD isomer with >99 % purity. The concentration was 50 % higher than that of the wide type. The results of this study showed the potential of producing meso-2,3-BD with high titer and purity through metabolic engineering.