Efficient (3S)-Acetoin and (2S,3S)-2,3-Butanediol Production from meso-2,3-Butanediol Using Whole-Cell Biocatalysis

Area of Science:

• Biotechnology
• Synthetic Biology
• Chemical Engineering

Background:

• (3S)-Acetoin and (2S,3S)-2,3-butanediol are crucial chiral building blocks for synthesizing valuable chemicals.
• Current fermentative production methods for these chemicals are challenging and inefficient.
• Meso-2,3-butanediol serves as a potential precursor for producing these chiral compounds.

Purpose of the Study:

• To establish a whole-cell biocatalysis strategy for efficient production of (3S)-acetoin and (2S,3S)-2,3-butanediol.
• To utilize meso-2,3-butanediol as a starting material for the biocatalytic synthesis.
• To develop engineered *E. coli* strains for high-yield and high-purity production.

Main Methods:

• Engineered *E. coli* co-expressing (2R,3R)-2,3-butanediol dehydrogenase, NADH oxidase, and *Vitreoscilla* hemoglobin for (3S)-acetoin production.
• Developed a second biocatalyst co-expressing (2S,3S)-2,3-butanediol dehydrogenase and formate dehydrogenase for subsequent (2S,3S)-2,3-butanediol synthesis.
• Optimized reaction conditions and employed synchronous catalysis with dual biocatalysts.

Main Results:

• Achieved a maximum (3S)-acetoin concentration of 72.38 g/L with 94.65% stereoisomeric purity.
• Produced (2S,3S)-2,3-butanediol with a concentration of 38.41 g/L and 98.03% stereoisomeric purity from meso-2,3-butanediol.
• Demonstrated the feasibility of a two-step whole-cell biocatalysis process from meso-2,3-butanediol.

Conclusions:

• The developed whole-cell biocatalysis strategy offers a promising alternative for producing (3S)-acetoin and (2S,3S)-2,3-butanediol.
• Meso-2,3-butanediol can be effectively converted into valuable chiral chemicals using engineered microorganisms.
• This approach highlights the potential of synthetic biology for sustainable chemical production.