PHENYLALANINE PRODUCTION BY PERIODIC INDUCTION OF GENE-EXPRESSION USING A TEMPERATURE-DISTRIBUTED DUAL FERMENTER SYSTEM

For the enhancement of phenylalanine production by Escherichia coli AT2471 harboring plasmid pSY130-14, we employed a circulating cultivation system composed of a conventional stirred fermentor and a plate heat exchanger (PHE)-type fermentor. Periodic induction of gene expression was achieved by circulating the culture liquid between the two fermentors at different temperatures. Production of phenylalanine was 28.5 g/l when the temperature and residence time of the stirred and PHE fermentors were maintained at 38.5-degrees-C for 30 min, and at 43.5-degrees-C for 5 min, respectively. These results indicate that phenylalanine production can be increased 55% by periodic induction using this novel, dual-fermenter, temperature-distributed cultivation system compared with that of single-vessel culture at a constant temperature.