Results and discussion . Construction of recombinant Escherichia coli . According to the construction method of recombinant E. coli , the whole genomic DNA of E. coli was used as the template, Ec TDH-F and Ec TDH-R were used as the primers for PCR amplification, and the amplified products were subjected to agarose gel electrophoresis, as shown in Additional file 1 : Figure S1A. The PCR product was purified with the kit, and the purified product and pACYCDuet-1 vector were si...