Enhanced acetoin production by Serratia marcescens H32 with expression of a water-forming NADH oxidase.
Cofactor engineering was employed to enhance production of acetoin by Serratia marcescens H32. 2,3-Butanediol was a major byproduct of acetoin fermentation by S. marcescens H32. In order to decrease 2,3-butanediol formation and achieve a high efficiency of acetoin production, nox gene encoding a water-forming NADH oxidase from Lactobacillus brevis was expressed. Batch fermentations suggested the expression of the NADH oxidase could increase the intracellular NAD(+) concentration (1.5-fold) and NAD(+)/NADH ratio (2.9-fold). Meanwhile, 2,3-butanediol was significantly decreased (52%), and the accumulation of acetoin was enhanced (33%) accordingly. By fed-batch culture of the engineered strain, the final acetoin titer up to 75.2g/l with the productivity of 1.88 g/(lh) was obtained. To the best of our knowledge, these results were new records on acetoin fermentation ever reported.
State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Meilong Road 130, Shanghai 200237, PR China.
Jian-An
JA
Sun
Liao-Yuan
LY
Zhang
Ben
B
Rao
Ya-Ling
YL
Shen
Dong-Zhi
DZ
Wei
D000093:Acetoin / Q000302:isolation & purification / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D024861:Genetic Enhancement / Q000379:methods*; D052196:Levilactobacillus brevis / Q000235:genetics / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism*; D009247:NADH, NADPH Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D012706:Serratia marcescens / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D013045:Species Specificity; D014867:Water / Q000378:metabolism*
D009097:Multienzyme Complexes; D011994:Recombinant Proteins; D014867:Water; D000093:Acetoin; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases