By Increasing The Metabolic Flux Of The Pyruvate Node To Improve The Yield Of The Class Of Human Collagen Ii

Recombinant Escherichia coli BL21 is used to produce human-like collagen.To improve human-like collagen production, pyruvate was added to the zymotic fluid at the phase of expression of human-like collagen. And response surface methodology (RSM) was adopted to optimize the adding time and dosage of pyruvate and the concentration of phosphate buffer. Finally, the adding time of pyruvate was at the point of induction, the optimal dosage of pyruvate and the concentration of buffer were 8.23 mmol·L-1 and 0.17 mol·L-1, respectively. Under the optimal cultivation condition, Cell OD600 was increased 28.72% compaired to the control group, the maximal production of human-like collagen could be up to 0.29 g·L-1 which was 11.54% higher than that of the control group.Based on the optimized results of flask experiment, the adding time and dosage of pyruvate was choosen to continue the fermenter experiment. The experiment results shown that when the recombinant Escherichia coli BL21 cells were cultivated under the condition that the adding time of pyruvate was at 1h after induction and the dosage of pyruvate was 15.84mmol/L the production of human-like collagen would be improved. And the highest dry cell density (69.6g/L dry cell weight) and human-like collagen production (11.87 g/L).