Isolation and cultivation of transglutaminase-producing bacteria from seafood processing factories

Abstract

Microbial transglutaminase (MTGase) is a transferase that catalyzes the acyl transfer reaction. MTGase has been applied to many protein containing foods to improve their textural property. Screening of MTGase producing microorganisms from various sources might lead to the discovery of novel MTGase with different characteristics. In this study, MTGase producing microorganisms were screened from soils, wastewater and floc-floating on wastewater from seafood processing factories by the filter paper disc (FPD) assay. The MTGase-positive colonies were confirmed by the hydroxamate assay in SPY medium. 95% of 312 FPD positive isolates showed the MTGase activity by hydroxamate assay in the SPY medium after cultivation at 37˚C for 36 h. Based on the assay, 15.86% of the tested colonies were considered as high MTGase activity colonies. The MTGase positive isolates, C1112, C1714 and C2361 were identified by 16s rDNA as neighbor of Providencia stuartii, Providencia alcalifaciens and Enterobacter cloacae with the similarity at 99.2, 97.3 and 99.9%, respectively. Enterobacter sp. C2361 and Providencia sp. C1112 were selected to cultivate in four media to compare the growth and MTGase productivity with Streptoverticillium mobaraense DSMZ 40847. The SPY medium was the most effective medium for production of MTGase by Enterobacter sp. C2361 and Providencia sp. C1112 with the activity of MTGase at 0.77+0.04 and 0.92+0.02 U/ml, respectively.