Ma Cui Qing, Xu Ping, Dou Yi Meng, Qu Yin Bo
State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, China.
Biotechnol Prog. 2003 Nov-Dec;19(6):1672-6. doi: 10.1021/bp0341242.
On an industrial scale, the production of pyruvate at a high concentration from the cheaper lactate substrate is a valuable process. To produce pyruvate from lactate by whole cells, various lactate-utilizing microorganisms were isolated from soil samples. Among them, strain WLIS, identified as Acinetobacter sp., was screened as a pyruvate producer. For the pyruvate preparation from lactate, the preparative conditions were optimized with whole cells of the strain. The cells cultivated in the medium containing 100 mM of l-lactate showed the highest biotransformation efficiency from lactate to pyruvate. The optimized dry-cell concentration, pH, and temperature of reaction were 6 g/L, pH 7.0-7.5, and 30 degrees C, respectively. The influences of ethylenediaminetetraacetic acid (EDTA) and aeration on a biotransformation reaction were carried out under the test conditions. Under the optimized reaction conditions, l-lactate at concentrations of 200 and 500 mM were almost totally stoichiometrically converted into pyruvate in 8 and 12 h, respectively. About 60% of 800 mM of l-lactate was transformed into pyruvate in 24 h. This reduced conversion rate is probably due to the high substrate inhibition in biotransformation.
在工业规模上，从更廉价的乳酸底物中高浓度生产丙酮酸是一个有价值的过程。为了通过全细胞从乳酸生产丙酮酸，从土壤样品中分离出了各种利用乳酸的微生物。其中，被鉴定为不动杆菌属的WLIS菌株被筛选为丙酮酸生产者。对于从乳酸制备丙酮酸，用该菌株的全细胞优化了制备条件。在含有100 mM L-乳酸的培养基中培养的细胞显示出从乳酸到丙酮酸的最高生物转化效率。优化后的干细胞浓度、pH值和反应温度分别为6 g/L、pH 7.0 - 7.5和30℃。在测试条件下研究了乙二胺四乙酸（EDTA）和通气对生物转化反应的影响。在优化的反应条件下，浓度为200 mM和500 mM的L-乳酸分别在8小时和12小时内几乎完全按照化学计量转化为丙酮酸。800 mM的L-乳酸在24小时内约60%转化为丙酮酸。这种转化率降低可能是由于生物转化中高底物抑制作用。
