Premium
Purification and characterization of a novel lichenase from Bacillus licheniformis GZ‐2
Author(s) -
Gao Zhen
Publication year - 2016
Publication title -
biotechnology and applied biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.468
H-Index - 70
eISSN - 1470-8744
pISSN - 0885-4513
DOI - 10.1002/bab.1206
Subject(s) - bacillus licheniformis , molecular mass , enzyme , chemistry , biochemistry , enzyme assay , hydrolysis , escherichia coli , open reading frame , microbiology and biotechnology , chromatography , biology , gene , peptide sequence , bacteria , genetics , bacillus subtilis
A novel lichenase from Bacillus licheniformis GZ‐2 was purified to homogeneity by two steps ion‐exchange chromatography with a specific activity of 8231.3 U/mg. The purified enzyme showed as a single protein band with a molecular mass of 25 kDa. The optimum pH and temperature for the enzyme activity were 6.5 and 60 °C, respectively. The enzyme exhibited strict specificity for β ‐1,3–1,4‐ d ‐glucans. The kinetic parameters K m and V max were 5.11 mg/mL and 2097 µmol/Min/mg for lichenan and 7.42 mg/mL and 1440 µmol/Min/mg for barley β ‐glucan. Compared to most of the reported β ‐1,3–1,4‐glucanases (lichenase), the activity of the purified enzyme for lichenan was much higher than that for barley β ‐glucan. The main products of β ‐glucan hydrolyzed by the lichenase were cellubiosyltriose (DP3) and cellutriosyltraose (DP4). The lichenase gene from B. licheniformis GZ‐2 was cloned and sequenced. The open reading frame of gene gz‐2 contained 642 bp coding for a 214 amino acid mature protein. The gene was cloned into an expression vector pET 28a and expressed in Escherichia coli BL21. The activity in cell lysate supernatant was 137.9 U/mg.