Optimal conditions for hepatitis B core antigen production in shaked flask fermentation

The effects of various environmental factors such as pH (5, 6, 7, 8 and 9), temperature (30, 37 and 40°C) and rotational speed (150, 200 and 250 rpm) on the growth and the hepatitis B core antigen (HBcAg) production of Escherichia coli W3110IQ were examined in the present study. The highest growth rate is achieved at pH 7, 37°C and at a rotational speed of 250 rpm which is 0.927 h^-1. The effect of pH on cell growth is more substantial compared to other parameters; it recorded a 123% different between the highest growth rate (0.927 h^-1) at pH 7 and lowest growth at pH 5. The highest protein yield is achieved at pH 9, rotational speed of 250 rpm and 40°C. The yield of protein at pH 7 is 154% higher compared to the lowest yield achieved at pH 5. There is about 28% different of the protein yield for the E. coli cultivated at 250 rpm compared to that at 150 rpm which has the lowest HBcAg yield. The yield of protein at 40°C is 38% higher compared to the lowest yield achieved at 30°C.