Efficient bioconversion of 2,3-butanediol into acetoin using Gluconobacter oxydans DSM 2003

<jats:title>Abstract</jats:title> <jats:sec> <jats:title>Background</jats:title> <jats:p>2,3-Butanediol is a platform and fuel biochemical that can be efficiently produced from biomass. However, a value-added process for this chemical has not yet been developed. To expand the utilization of 2,3-butanediol produced from biomass, an improved derivative process of 2,3-butanediol is desirable.</jats:p> </jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>In this study, a <jats:italic>Gluconobacter oxydans</jats:italic> strain DSM 2003 was found to have the ability to transform 2,3-butanediol into acetoin, a high value feedstock that can be widely used in dairy and cosmetic products, and chemical synthesis. All three stereoisomers, <jats:italic>meso</jats:italic>-2,3-butanediol, (2<jats:italic>R</jats:italic>,3<jats:italic>R</jats:italic>)-2,3-butanediol, and (2<jats:italic>S</jats:italic>,3<jats:italic>S</jats:italic>)-2,3-butanediol, could be transformed into acetoin by the strain. After optimization of the bioconversion conditions, the optimum growth temperature for acetoin production by strain DSM 2003 was found to be 30°C and the medium pH was 6.0. With an initial 2,3-butanediol concentration of 40 g/L, acetoin at a high concentration of 89.2 g/L was obtained from 2,3-butanediol by fed-batch bioconversion with a high productivity (1.24 g/L · h) and high yield (0.912 mol/mol).</jats:p> </jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p> <jats:italic>G. oxydans</jats:italic> DSM 2003 is the first strain that can be used in the direct production of acetoin from 2,3-butanediol. The product concentration and yield of the novel process are both new records for acetoin production. The results demonstrate that the method developed in this study could provide a promising process for efficient acetoin production and industrially produced 2,3-butanediol utilization.</jats:p> </jats:sec>