A statistical experimental design to plastein synthesis which was catalyzed by transglutaminase, using the mixture of soy protein isolate(SPI) hydrolysate and whey protein isolate (WPI) hydrolysate, was investigated. Enzyme/Substrate(E/S:5-25U/g), pH(5-9) and temperature (35-65°C) were selected as major operating variables. To investigate the effects of variables to yield of plastein, the statistical experiment of Box-Behnken design(BBD) and Response Surface methodology(RSM) was employed. Regression analysis showed that the experiment data accorded with the predicted values obtained from quadratic regression equation in BBD with R-Squared of 0.9866 and F-value of 102.51. The optimum results estimated by BBD were as follows: E/S(19.5U/g), pH(6.8), and temperature(50.0°C), gave a maximum plastein yield of 54%. In the present experiment, the preliminary study on plastein functions such as foaming, emulsifying, were showed that plastein had a good biological function.
Enhanced production of poly glutamic acid by Bacillus sp. SW1-2 using statistical experimental design