Fig. 4.

The effect of codon optimization on the expression of TGase in S. lividans. The plasmid pTGO encoded TGase ORF with the optimized promoter (see Fig. 2b). The plasmid pTGOm encoded the same promoter as pTGO, and the TGase ORF was optimized according to the codon preference of S. lividans (see Fig. 3). The recombinant S. lividans TK24 that expressed pTGO or pTGOm was inoculated into 30 mL of medium (which contained 50 μg/mL apramycine) and cultured at 30 °C and 200 rpm for 3 days