earticle

영어

To improve phenylalanine ammonia lyase (E.C.4.3.1.5-PAL) activity in recombinant Escherichia coli, Someapproaches for improving phenylalanine ammonia lyase (PAL) activity in recombinant E. coli were developed followingpreliminary studies by means of response surface method. The results shown that permeabilization with combination of TritonX-100, cetyl trimethyl ammonium bromide (CTAB), and acetone enriched cellular recombinant PAL activity significantly,which improved over 10-fold as compared with the control (untreat cell), as high as 181.37 U/g. The optimum values for thetested variables were Triton X-100 0.108 g/L, CTAB 0.15 g/L, and acetone 45.2%(v/v). Furthermore, a second-order modelequation was suggested and then validated experimentally. It was indicated that addition of surfactants and organic solventsmade the cells more permeable and therefore allowed easier access of the substrate to the enzyme and excretion of theproduct, which increased the rate of transport of L-phenylalanine and trans-cinnamic acids. These improved methods of PALactivity enrichment could serve as a rich enzyme source, especially in the biosynthesis of L-phenylalanine.