苯丙氨酸解氨酶重组大肠杆菌产酶条件研究

Optimization of Production Conditions of Phenylalanine Ammonia-Lyase by Recombinant E.coli

为了提高重组苯丙氨酸解氨酶(PAL)活力,研究培养基初始pH值、种龄、接种量、装液量和发酵时间对重组PAL活力的影响,并用响应面分析法优化了培养条件。单因素最适培养条件为:发酵培养基初始pH7.0、种龄10h、接种量10%、装液量50ml、发酵时间24h。响应面优化后的结果表明,种龄、接种量和发酵时间对重组PAL活力影响较大,但三者之间没有显著的交互作用。优化后的产酶条件是:种龄13.3h、接种量10.7%、发酵时间25.5h、在此条件下,PAL活力比不优化的培养条件的酶活增加了15%左右,重组PAL酶活达到14.95U/ml。

Effects of initial pH value of fermentation medium, inoculation time, inoculation volume, broth volume in 250-ml flask and fermentation time on the activity of phenylalanine ammonia-lyase （PAL） produced by recombinant E. coli JM109 were investigated through single-factor test, and then the main affecting factors confirmed in single-factor test were optimized through response surface analysis （RSA）. The results showed that initial pH value of fermentation medium and broth volume in 250-ml flask are not main affecting factors, and they can be controlled at 6.5 to 7 and 50 ml, respectively; inoculation time, inoculation volume and fermentation time are main affecting factors, and their optimal levels are 13.3 h, 10.7 % and 25.5 h, respectively. By this optimization, the activity of PAL is increased by about 15%, reaching 14.95 U/ml.