Mechanism of microbial production of AC and BD optical isomers and
substrate specificity of butanediol dehydrogenase
Abstract
3-Hydroxybutanone (Acetoin, AC) and 2,3-butanediol (2,3-butanediol, BD)
are two essential four-carbon platform compounds with numerous
pharmaceutical and chemical synthesis applications. AC and BD have two
and three stereoisomers, respectively, while the application of the
single isomer product in chemical synthesis is superior. AC and BD are
glucose overflow metabolites produced by biological fermentation from a
variety of microorganisms. However, the AC or BD produced by
microorganisms using glucose is typically a mixture of various
stereoisomers. This was discovered to be due to the simultaneous
presence of multiple butanediol dehydrogenases (BDH) in microorganisms,
and the AC and BD can be interconverted under BDH catalysis. In this
paper, beginning with the synthesis pathways of microbial AC and BD, we
review in detail the studies on the formation mechanisms of different
stereoisomers of AC and BD, summarize the properties of different types
of BDH that have been tabulated, and analyze the structural
characteristics and affinities of different types of BDH by comparing
them using literature and biological database data. We also review
recent work on the production of octadecanoic acid. Using
microorganisms, the recent research on the production of optically pure
AC or BD was also reviewed.