Open AccessA novel α-galactosidase from the thermophilic probiotic Bacillus coagulans with remarkable protease-resistance and high hydrolytic activity
Author(s) -
Ruili Zhao,
Rui Zhao,
Yishuai Tu,
Xiaoming Zhang,
Liping Deng,
Xiangdong Chen
Publication year - 2018
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0197067
Subject(s) - bacillus coagulans , probiotic , thermophile , protease , food science , microbiology and biotechnology , hydrolysis , chemistry , biology , extremophile , enzyme , biochemistry , bacteria , fermentation , genetics
A novel α-galactosidase of glycoside hydrolase family 36 was cloned from Bacillus coagulans , overexpressed in Escherichia coli , and characterized. The purified enzyme Aga-BC7050 was 85 kDa according to SDS-PAGE and 168 kDa according to gel filtration, indicating that its native structure is a dimer. With p -nitrophenyl-α- d - galactopyranoside (pNPGal) as the substrate, optimal temperature and pH were 55 °C and 6.0, respectively. At 60 °C for 30 min, it retained > 50% of its activity. It was stable at pH 5.0–10.0, and showed remarkable resistance to proteinase K, subtilisin A, α-chymotrypsin, and trypsin. Its activity was not inhibited by glucose, sucrose, xylose, or fructose, but was slightly inhibited at galactose concentrations up to 100 mM. Aga-BC7050 was highly active toward pNPGal, melibiose, raffinose, and stachyose. It completely hydrolyzed melibiose, raffinose, and stachyose in < 30 min. These characteristics suggest that Aga-BC7050 could be used in feed and food industries and sugar processing.