Fig. 1.

Production of TGase by S. lividans TK24/pIJ86/tgl. a The gene structure of tg1. b Construction of TGase expression plasmid pIJ86/tg1. c TGase activity assay of the culture supernatants of Streptomyces strains. d SDS-PAGE analysis of the TGases in the culture supernatants of Streptomyces strains. Labeling for (a): The numbers in the illustration indicate the base positions. Labeling for (c): 1: S. lividans TK24/pIJ86/tgl (the recombinant strain that expresses the S. hygroscopicus TGase ORF using the TGase endogenous promoter), 2: S. lividans TK24/pIJ86 (the control strain that carries pIJ86), 3: S. lividans TK24 (the control strain without the expression plasmid), 4: S. hygroscopicus WSH03-13 (the wild type strain that produces TGase). Labels for (d): M: protein marker, 1: S. lividans TK24/pIJ86/tgl, 2: S. lividans TK24/pIJ86, 3: S. lividans TK24, 4: S. hygroscopicus WSH03-13. The recombinant S. lividans TK24 were inoculated into 30 mL of medium (which contained 50 μg/mL apramycine) and cultured at 30 °C and 200 rpm for 48 h