乳酸乳球菌中双乙酰代谢支路的调控  

Genetic manipulation of the pathway for Diacetyl metabolism in Lactococcus Lactis

作　　者：杨丽杰[1] 王俊沪[1] 

机构地区：[1]东北农业大学,黑龙江哈尔滨150030

出　　处：《中国乳品工业》2004年第5期24-29,共6页China Dairy Industry

基　　金：黑龙江省"十五"科技重点攻关项目(BA01B302-6)

摘　　要：描述了从柠檬酸代谢、糖酵解来形成双乙酰的途径及其调节思路,并提出乳酸酸乳球菌的混合酸发酵及其调控机理,对双乙酰代谢支路的的遗传修饰方法进行了综述。结果表明,在特定条件下,有些乳酸菌从同型乳酸发酵转道成为异型乳酸发酵而产生其他代谢物(如甲酸或CO2,乙酸和乙醇),这种变化涉及到丙酮酸代谢的遗传修饰降低乳酸脱氢酶(LDH)活力或α-乙酰乳酸脱羧酶(ALD)活力、增加丙酮酸甲酸盐裂解酶(PFL)(厌氧条件)或α-乙酰合成酶(ALS)或丙酮酸脱氢酶(PDH)活力(好氧条件),这些方法会有效地将糖转化成为双乙酰。对双乙酰代谢支路的调控主要集中在超产als或ilvBN,失活ldh,pfl,aldB或与超产NADH-氧化酶方法相结合使用。The metabolic pathway involved in citrate fermentation and mixed acid fermentation to form Diacetyl is described in this paper. Genetic modification of the gene involved in the pathway for Diacetyl metabolism in Lactococcus lactis are also reviewed. Under certain conditions, homolactic behavior is lost and increased amounts of other metabolites, such as formate or CO2, acetate, and ethanol, are produced in what is generally called mixed acid fermentation.Such a shift involves a genetic modification of pyruvate metabolism with a decreased activity of lactate dehydrogenase(LDH) or α-acetolactate decarboxylase (ALD), an increase in pyruvate formate lyase(PFL) (anaerobic conditions) or α-acetolactate synthase (ALS) or pyruvate dehydrogenase (aerobic conditions) activity for the efficient conversion of sugar into diacetyl .Studies focus on the overproduction of ALS (als or ilvBN), inactivation of lactate dehydrogenase (LDH) ,pyruvate formate lyase , or ALDB , or a combination overproduction of NADH oxidase with one of these strategies.

关 键 词：乳酸乳球菌 双乙酰 混合酸发酵 遗传修饰 调控机理 

分 类 号：TS252.1[轻工技术与工程—农产品加工及贮藏工程]