Screening of Strains with fibrinolytic activity and angiotensin-converting enzyme inhibitory activity from doenjang

As a first step to develop a doenjang possessing functional properties, microbial strains possessing proteolytic activity, fibrinolytic activity, and angiotensin-converting enzyme (ACE) inhibitory activity were screened and isolated from Korean traditional doenjang. First, total 264 isolates showing proteolytic activity were isolated from 14 different doenjang samples. Among them, 4 strains producing both of fibrinolytic activity and ACE inhibitor into the culture medium were selected. The levels of ACE inhibitory effect of G19, G26, P16, and P25 strains were about 82.5, 78.5, 74.5, and 75.6% of inhibition ratio in soybean powder broth, respectively. All isolates were identified as Bacillus amyloliquefaciens based on SDS-PAGE profiles of whole cell proteins and 16S rRNA gene sequence analysis. The result implied that the selected Bacillus strains could be used for the development of doenjang possessing functional properties as potential starter.