Production of transglutaminase by Streptomyces isolates in solid-state fermentation.

Abstract

To screen Streptomyces isolates for transglutaminase (TGase) production in solid-state fermentation (SSF) on various substrates. Streptomyces mobaraensis NRRL B-3729, Streptomyces paucisporogenes ATCC 12596 and Streptomyces platensis NRRL 2364 strains were screened for extracellular TGase production in SSF on different substrates. High-protein-content beans, peas and lentils proved to be the best substrates. Good TGase production was obtained on liver kidney beans and green mung beans in a 4- to 6-day SSF. Temperature optima of the enzymes varied between 45 to 50 degrees C. Molecular weight determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS PAGE) indicated similar size ( approximately 37 kDa) for all three enzymes. TGase was the dominating protein band on SDS PAGE for two Streptomyces strains in SSF extracts. Other enzymes were present in smaller quantities. Streptomyces mobaraensis NRRL B-3729, S. paucisporogenes ATCC 12596 and S. platensis NRRL 2364 strains were successfully propagated under SSF conditions on crushed/milled liver kidney bean and green mung bean to obtain good level of TGase. Owing to much reduced production cost and direct applicability, SSF TGase without downstream processing (cheap in situ enzyme, crude enzyme) may be an excellent candidate for some nonfood applications.