Abstract: The resources and separation methods of the lactate dehydrogenase (LDH) and its catalytic characteristics on synthesis of phenyllactic acid (PLA) were reviewed. Firstly, the resources of microorganisms for LDH and the isolation approaches of this enzyme from those lactic acid bacteria were discussed. It was found that the chromatography using cryogels could be an effective and novel one-step approach for the purification of LDH from crude broth having the advantages like high purity. Then, the crucial mechanisms, the optimized conditions, the enzyme engineering modification methods, as well as the influences of pH, temperature and heat resistance parameters on the biosynthesis of PLA by LDH with phenylpyruvic acid as the key substrate, were discussed. It was found that the optimal reaction conditions, such as pH and temperature, for the catalytic activities of LDH from different strains were quite different during the biosynthesis of PLA. Finally, recent studies regarding the enzyme engineering modification of LDH in the biosynthesis of PLA were summarized and compared. It was found that the catalytic activities of LDH in the biosynthesis of PLA from phenylpyruvic acid could be improved by the genetic modification and the co-expressing systems of LDH with coenzymes could be considered as the important future direction in this field.

Key words: lactate dehydrogenase, lactic acid bacteria, phenyllactic acid, phenylpyruvic acid, purification

摘要： 对乳酸脱氢酶的来源、分离纯化及其催化合成苯乳酸的研究进行了综述。首先，分析了乳酸脱氢酶的微生物来源，重点对乳酸菌中乳酸脱氢酶的分离方法及相关研究现状进行了总结，认为采用晶胶层析方法可直接一步从破胞液中分离高纯度的乳酸脱氢酶；然后，分析了乳酸脱氢酶催化苯丙酮酸的核心反应机理、最适条件及其工程改造，讨论了pH、温度、耐热性等参数对乳酸脱氢酶催化苯丙酮酸的影响，表明不同菌种乳酸脱氢酶催化苯丙酮酸最适pH和温度有很大差异；最后，对比了乳酸脱氢酶酶法合成苯乳酸相关工程改造的研究工作，指出基因修饰能有效提高乳酸脱氢酶酶法对苯丙酮酸的催化能力，同时乳酸脱氢酶与辅酶共表达体系的构建是下一步研究的重点方向。

关键词: 乳酸脱氢酶, 乳酸菌, 苯乳酸, 苯丙酮酸, 分离纯化