苯乳酸是由乳酸菌属等微生物代谢合成的一种新型食品防腐剂。今利用透性化干酪乳杆菌(Lactobacillus casei B3)细胞转化苯丙酮酸，合成得到了苯乳酸，并通过单因素实验和正交实验，确定了适宜的转化条件，即：干酪乳杆菌在−20℃冷冻6 h后用于转化，苯丙酮酸浓度为8 g⋅L−1，葡萄糖浓度为14 g⋅L−1，菌浓度为100 g⋅L−1，pH值为8.0，温度为35℃，转速为75 r⋅min−1，转化时间为4 h；优化条件下苯乳酸的收率达65.5%，转化液中苯乳酸浓度达到了5.3 g⋅L−1。%Phenyllactic acid is a novel food preservative produced by some strains of lactic acid bacteria. In this work, phenyllactic acid was synthesized from phenylpyruvic acid with permeabilizedLactobacillus casei B3cells. The biotransformation process was optimized by single factor and orthogonal experiments, which resulted in an optimized transformation condition as 6 h freezing time for theL. casei B3 cells at−20℃ with phenylpyruvic acid concentration of 8 g⋅L−1, glucose concentration of 14 g⋅L−1, cell concentration of 100 g⋅L−1, pH value of 8.0, temperature of 35℃ and shaking rate of 75 r⋅min−1 for 4 h. The phenyllactic acid yield (defined as the molar ratio of the final phenyllactic acid to the substrate phenylpyruvic acid in the broth) was 65.5% and the phenyllactic acid concentration reached to 5.3 g⋅L−1 under such conditions.
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