乳酸乳球工程菌表达L-苯丙氨酸解氨酶的工艺优化

目的]提高乳酸乳球工程菌表达L-苯丙氨酸解氨酶的水平.方法]对培养基种类、接种量、培养温度、诱导剂浓度、磷酸甘油二钠浓度等因素进行了优化.结果]使用DifcoTM M17 Broth培养基培养乳酸乳球菌时,L-苯丙氨酸解氨酶表达活性最高;磷酸甘油二钠对L-苯丙氨酸解氨酶表达活性有较大影响,可提高活性93.8％.通过正交试验,得到PAL最佳表达条件为接种量2.0％,培养温度30℃,磷酸甘油二钠浓度2.0％,诱导剂浓度10.0 μg/L. PAL表达酶活可达3.05 IU/ml.结论]在发酵扩大培养中优化了L-苯丙氨酸解氨酶在乳酸乳球菌中的表达条件,为今后生产及应用提供参考.

Process Optimization of L-phenylalanine Ammonialyase Expression in Lactococcus lactis

Objective] In order to improve the level of L-phenylalanine ammonialyase expression in Lactococcus lactis.Method] The kinds of culture medium,inoculum concentration,incubation temperature,inducer concentration,two sodium glycerophosphate concentration were optimized. Results] The cultured L.lactis medium using DifcoTM M17 Broth,L-phenylalanine ammonia lyase activity is highest; two sodium glycerophosphate on L-phenylalanine ammonialyase expression significantly affected the enzyme activity,can improve the activity of 93.8％.Through the orthogonal experiment,the optimal conditions for PAL expression were inoculum concentration 2.0％,incubation temperature 30 ℃,two sodium glycerophosphate concentration 2.0％,inducer concentration 10.0 μg/L.The expression of PAL enzyme activity was 3.05 IU/ml.Conclusion] The study optimized expression condition of L-phenylalanine ammonialyase in Lactococcus lacti,and provided a reference for future production and application.