earticle

영어

Effects of controlled- and uncontrolled-pH operations on phenylalanine ammonia lyase (PAL) production by arecombinant Escherichia coli strain were investigated at uncontrolled-pH (pHUC) and controlled-pH (pHC) of 5.5, 6.0, 6.5, 7.0,7.5, 8.0, and 8.5 in bioreactor systems. The results showed that the recombinant PAL activity was improved significantly bycontrolled pH strategy. Among the pHC operations, the highest PAL activities were obtained under pHC 7.5 strategy where cellmass (OD600 nm) and PAL activity was 1.3 and 1.8 fold higher than those of pHUC, respectively. The maximum PAL activityreached 123 U/g. The pHC 7.5 strategy made recombinant plasmid more stable and therefore allowed easier expression of PALrecombinant plasmid, which increased PAL production. It was indicated that the new approach (controlled-pH strategy)obtained in this work possessed a high potential for the industrial production of PAL, especially in the biosynthesis of L-phenylalanine.