α-Glucosidase inhibitory activity and protease characteristics produced by Bacillus amyloliquefaciens

Abstract

In this study, three GRAS (generally recognized as safety) strain was isolated from Doenjang and Cheonggukjang and identified as a protease-producing microorganism, following the appearance of a clear zone around its colony when cultured on a medium containing skim milk. Based on an analysis of the nucleotide sequence of 16S ribosomal RNA, the strains wereas identified as Bacillus amyloliquefaciens and wereas therefore named Bacillus amyloliquefaciens CDD5, Bacillus amyloliquefaciens CPD4, and Bacillus amyloliquefaciens CGD3. Here, we analyzed the protease and α-glucosidase inhibitory activities of the three B. amyloliquefaciens strains. Among the isolated strains, B. amyloliquefaciens CGD3 exhibited the highest protease activity (9.21 U/mL, 24 hr). The protease activities of B. amyloliquefaciens CDD5 and B. amyloliquefaciens CPD4 reached 1.14 U/mL and 8.02 U/mL, respectively, at 48 hr. The proteases from the three B. amyloliquefaciens strains showed the highest activities within a pH range of 8.0-9.0 at 50°C, and casein was found to be the preferred substrate on evaluating enzyme activity in the substrate specificity assay. The B. amyloliquefaciens strains exhibited maximal growth when the nutrient broth medium had an initial pH within the range of 5.0-10.0, 6-9% sodium chloride (NaCl), and 5% glucose. B. amyloliquefaciens CDD5 exhibited a low α-glucosidase inhibition rate (5.32%), whereas B. amyloliquefaciens CPD4 and B. amyloliquefaciens CGD3 exhibited relatively higher inhibition rates of 96.89% and 97.55%, respectively.

Isolation and Characterization of Protease Producing B. amyloliquefaciens JH-35 from Food Waste

“…WRD-2 (Ok et al, 2001), 청국장에서 분리한 Bacillus sp. JK-1 (Kim, 2007)와 B. amyloliquefaciens (Lee et al, 2015), 재래식 된장 에서 분리한 B. licheniformis (Bae and Yoon, 2012), 해수에 서 분리한 Pseudoaltermonas donghaensis HJ51 (Oh et al, 2015)와 Micrococcus sp. PS-1 (Jin et al, 2013) 등의 많은 연구가 이루어 지고 있다.…”