Isolation of Streptomyces Species from Soil and its Medium Optimization for Microbial Transglutaminase Production by Box-Behnken Design

Gopal Samy B*, Sujitha S, Thya

Abstract

Transglutaminase (E.C. 2.3.2.13) are a family of enzymes that catalyze the covalent bond formation between open amine groups. They are widely used in food industries and their demand rises daily. Though they are available in mammalian tissues, fish and plants, the complex separation and purification process led to the search of Microbial Transglutaminase (MTGase). Finding a new microbial source of transglutaminase and the medium composition for MTGase production were the purpose of this work. Six Different types of Actinomycetes like strains were isolated from soil sample and two of them named PG03 and PG06 were selected based on their ability to produce 23 mg/ml and 21 mg/ml MTGase enzyme respectively. Strain PG03 was chosen for further studies and it was found to be a Streptomyces species. Standard enzyme production media composition is modified and tested to facilitate the optimized MTGase activity. Strategies like finest nitrogen and carbon source selection, revealing the key ingredients of media by full factorial design and their optimal concentration Box-Behnken design were adopted. At the 95% confidence level, second order polynomial model was applied to fit the research outcome. Under the proposed optimized conditions, the model predicted a transglutaminase yield of 21.7 mg/ml, very closely matching the experimental value of 24.1 mg/ml. The F-test was greater than the table value of 2.82 and the p-value of 0.004 clearly reveals that this regression was statistically significant at the 95% confidence level. Further, the proposed model has the ability to elucidate 48.8% response variation as indicated by the R2 of the regression value.

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