Potential Starter Culture Isolated from Traditionally Fermented YangJiang Lobster Sauce and Protease Characteristics Research

The purpose of this study was to isolate strains from traditionally fermented Yangjiang lobster sauce, those can use as potential starter culture for the pure fermentation under controlled conditions of temperature and pH. The result was found that seven strains isolated by PDA medium, and then they were evaluated for production of protease on skim milk agar. Especially three strains, which Rhizopus oryzae, Aspergillus oryzae and Pichia burtonii exhibited high proteolytic activities with area of clear zone. Seven strains identified by morphological and phylogenetic analysis, which studies based on the 16S, 18S ribosomal gene sequences and 26S rDNA D1 / D2 sequence, showed that two pathogens strains survived in traditional Yangjiang lobster sauce. The research investigated effects of pH and temperature on activity and stability of protease, effect of metal ions and NaCl on protease activity in three high proteolytic activity strains.