3-Phenyllactic acid production by substrate feeding and pH-control in fed-batch fermentation of Lactobacillus sp. SK007.

3-Phenyllactic acid (PLA), which is produced by some strains of lactic acid bacteria (LAB), is a known antimicrobial agent with a broad spectrum. Batch and fed-batch fermentation by the strain Lactobacillus sp. SK007 for PLA production have been reported. With batch fermentation without pH-control, PLA production yield was 2.42 g L(-1). When fed-batch fermentation by Lactobacillus sp. SK007 was conducted in 3 L initial volume with pH-control at 6.0 and intermittent feeding, which was developed after fermentation for 12 h and every 2 h with 120 mL 100 g L(-1) PPA phenylpyruvic acid (PPA) and 50 mL 500 g L(-1) glucose each time, PLA production yield reached 17.38 g L(-1). The final conversion ratio of PPA to PLA was 51.1%, and the PLA production rate was 0.241 g L(-1) h(-1). This indicated that PPA was the ideal substrate for PLA fermentation production, and fed-batch fermentation with intermittent PPA feeding and pH-control was an effective approach to improve PLA production yield.