Abstract:

Microbial transglutaminase (MTG)-producing strain Streptoymyces mobaraensis (S. mobaraensis) was subjected
to mutagenesis using UV irradiation and diethyl sulfate (DES) treatment and the resulting colonies were screened by a high
throughput method. Results showed that the combined mutagenesis had better performance than single mutagenesis. The
high-yield MTG-producing mutants had either a higher MTG protein expression or a shortened maturation time of MTG.
Among these, one mutant had the highest yield of 7.02 U/mL enzymatic activity, which was 54% higher than that of the
wild-type strain. Further study found that this strain expressed MTG products 24 hours earlier than the wild-type one did.
However, the yield of MTG could be highly inhibited by the zymogen pro-MTG.

Key words: microbial transglutaminase (MTG), Streptomyces mobaraensis, diethyl sulfate (DES), ultraviolet (UV), combined mutation