Screening the culture medium and optimal fermentation conditions for the production of transglutaminase by the Streptomyces sp. strain TG1G1

Abstract

Microbial transglutaminase (MTGase) catalyses the creation of isopeptide bonds between the γ-carboxamide group of the glutamine residues as acyl donors and the ε-amine group of different compounds as a receptor that modifies protein structure. This research objective was to improve the transglutaminase activity produced by a strain of Streptomyces sp. TG1G1 by choosing an appropriate medium and optimising fermentation conditions. The study started with screening different media formulations and then various fermentation conditions, including pH, temperature, and time for optimal MTGase production. The findings of these studies revealed that the maximum MTGase activity was shown in the medium composed of peptone (1%), yeast extract (0.2%), MgSO₄.7H₂O (0.2%), KH₂PO₄ (0.4%), Na₂HPO₄ (0.5%), soybean powder (1.5%), potato starch (1.5%), and glucose (0.5%). MTGase activity reached the highest level (43.6 mU/ml) under the following culture conditions: pH 7.5, temperature of 30^oC, for 4 days of culture. In addition, MTGase activity increased when the culture medium contained three carbon sources, including soybean meal, potato starch, and glucose. These results propose appropriate culture conditions and medium factors for transglutaminase biosynthesis of Streptomyces sp. strain TG1G1.