Acetoin production enhanced by manipulating carbon flux in a newly isolated Bacillus amyloliquefaciens

► An acetoin high-producing Bacillus amyloliquefaciens FMME044 was newly isolated. ► The mechanism of exchange of 2,3-butanediol and acetoin is explained. ► A novel strategy of manipulating carbon flux to acetoin is proposed. ► 51.2 g/L acetoin with yield of 0.43 g/g and productivity of 1.42 g/L/h was achieved.