[Gene regulation to lactic acid bacteria for increasing production of flavor metabolite].
Abstract: The major flavor substances Lactic acid bacteria produced include the buttermilk aroma butanedione, the yoghurt flavor acetaldehyde and the amino acid. Metabolic engineering in LAB had focused primarily on rerouting of pyruvate metabolism towards butanedione or acetaldehyde to improve the flavor of fermented milk, which has considerable economic value. The typical yogurt flavor is caused by acetaldehyde produced through many different pathways. The attention was focused on one specific reaction for acetaldehyde formation catalyzed by serine hydroxymethyltransferase, which encoded by the glyA gene. In addition, the efficient conversion of glucose into acetaldehyde was achieved by over-expression of pyruvate decarboxylase and NADH oxidase in LAB. The concentration of acetaldehyde derived from this regulation is higher than the other strategy. As for the regulation of butanedione, it was focused on combinating inactivation of alpha-acetolactate decarboxylase with low lactate dehydrogenase activity, or with overproduction of NADH-oxidase, or with overproduction of alpha-acetolactate synthase. Then the possibility of co-regulation with certain three kinds of enzyme above was recommended.
Han
Xi-Yan
XY
Key Lab of Dairy Science, Ministry of Education, College of Food Science and Engineering, Northeast Agricultural University, Harbin 150030, China. hanxiyan_0_0@163.com
Sun
Da-Qing
DQ
Xiang
Li
L
Huo
Gui-Cheng
GC
Jiang
Yu-Jun
YJ
D000079:Acetaldehyde / Q000378:metabolism*; D004852:Epoxy Compounds / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D048668:Lactobacillus delbrueckii / Q000235:genetics* / Q000378:metabolism; D013294:Lactococcus lactis / Q000235:genetics* / Q000378:metabolism; D007934:Leuconostoc / Q000235:genetics* / Q000378:metabolism; D048249:Streptococcus thermophilus / Q000235:genetics* / Q000378:metabolism
D004852:Epoxy Compounds; C007366:diepoxybutane; D000079:Acetaldehyde