Improved productivity of recombinant human-like collagen ii by supplying amino acids encoded by rare codons

Abstract

Amino acids, the key growth factors, affect cell growth and metabolism directly or indirectly. In order to enhance the production of human-like collagen (HLC) II, amino acids were added into initial fermentation broth and response surface methodology (RSM) was used to screen the suitable varieties of amino acids and optimize their doses. Single-factor experiment showed that arginine, proline, threonine, cysteine and methionine could increase the production of human-like collagen II by 23.32 to 66.95%. With the optimization method of RSM, the final optimal concentration of arginine, cysteine and methionine were confirmed to be 5.95, 8.73 and 0.35 g·L-1 respectively. Under the optimal cultivation condition the maximal production of HLC reached 0.586 g·L-1 which was 150.43% higher than that of the control group at 0.234 g·L-1, while the acetate accumulation was 12.51% less than that of the control. Key words: Human-like collagen, methionine, rare condons, recombinant Escherichia coli, response surface methodology.