Science and Education Publishing Journal of Food and Nutrition Research 2333-1240 2 12 2014 11 21 Control of the Ratio of Inducer to Cell Concentration to Enhance the Phytase Production in Recombinant Pichiapastoris 980 984 EN Housheng Hong College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China Zhaosheng Min Huiming Guo JFNR201421219 10.12691/jfnr-2-12-19 2014 11 12 2014 11 18 2014 11 21 Phytase production by Pichiapastoris was used as a case to study the mechanism and strategy for optimization of heterologous protein production. It was found that the ratio of inducer-methanol to cell concentration had a significant influence on phytase production. In this case, we found that the optimum initial cell concentration and methanol concentration were 85 g/L and 10 g/L, respectively. During induction period, an easy-to-control methanol feeding method was proposed according to the optimal ratio of methanol to cell concentration at a range of 0.063 -0.132 g/g, and phytase activity and productivity reached 53984 U/mL and 529.25 U/(mL·h), respectively. The method for optimization of phytase production through controlling the optimal ratio maybe provide an alternative idea to enhance other heterologous protein production with P. pastoris.