earticle

영어

In recent years, 2,3-butanediol (2,3-BDO) which is a colorless and odorless 4-carbon chemical has been applied wildly in industries such as synthetic rubber industry, antifreeze substance, food and cosmetics pharmaceuticals. Actually, researchers have already been interested in 2,3-BDO biosynthesizing mechanisms since a century ago. In 2,3-BDO synthesis pathway from pyruvate, two pathways exist with respect to different aeration environments. Pyruvate changes to acetolactate and then acetoin to 2,3-BDO directly under anaerobic condition, while the aerobic pathway is constructed by the change from acetolactate to diacetyl firstly and then diacetyl to acetoin and 2,3-BDO. Since two different pathways regulate NADH balance in different mechanism and influence greatly on 2,3-BDO synthesis, the identification of the working mechanisms in these pathways is of importance.In this study, Klebsiella pneumoniae strain was utilized to constructed 3 different mutant strains (by over-expressing budB, budA and budC genes) with respect to 2,3-BDO synthesis pathway firstly. Then, continuous cultures under aerobic and anaerobic conditions were performed using these strains in order to obtain the steady-state data. Extracellular metabolite profiles under steady-state were used to perform metabolic flux analysis for data analysis and calculations of the enzyme working mechanisms. The research helped clarify different intracellular functions under different oxygen supply situation and is beneficial for improve 2,3-BDO productivity.