Isolation and identification of a transglutaminase producing strain and its tgl cloning and expression

By using the dilution plate method, 166 bacterial strains isolated from soil samples and one strain, TGase1318, which could produce transglutaminase, was obtained after screening with gel formation method and Folk's colorimetry method.The strain was identified as Bacillus subtilis according to the morphology, physiological and biochemical characters as well as 16 S r DNA sequence homological analysis.The tgl gene, which was a 738 bp long nucleotide, was cloned from the strain and encoded a 245 residue long TGase.Homological analysis of TGase peptide sequence revealed that it shared 94% ¹00% conservation with TGase of other B.subtilis strains released by NCBI.The expression recombinant plasmids p TZ- tgl and p ET21b- tgl were constructed and transformed into B.subtilis WB800 and E. coli BL21, respectively. The results of BSA crosslink at 70℃ indicated the tgl gene was expressed in both B.subtilis and E.coli with TGase activity.This study laid a foundation for the application of TGase from B.subtilis TGase1318 to food industry.