Abstract:

In the present study, we optimized the conditions for purifying β-1,3-1,4-glucanase produced by Mucor petrinsularis
M-28 in solid-state fermentation, and characterized some enzymatic properties of the purified enzyme. The cultured medium was
extracted with acetic acid-sodium acetate buffer at pH 5.5 by shaking at 200 r/min for 30 min and the crude enzyme extract was
salted out with 80% saturated ammonium sulfate, dialyzed for 24 h, and chromatrographed on a Sephadex G-100 column. As a
result, two protein peaks were obtained as determined by UV spectrophotometry. One of these was found to be enzymatically
active. The pooled activity peak was highly concentrated using polyethylene glycol before being analyzed for purity by SDSPAGE.
It turned out that the purified enzyme displayed a single protein band with a molecular weight of 17.2 kD. Its specific
activity was 225.02 U/mg, which was 3.48 times more active than the crude enzyme. The optimum temperature and pH for the
enzyme activity were 40 ℃ and 6.0, respectively. The enzyme appeared to be stable at temperatures between 40 and 50 ℃ and
in the pH range of 4.0–7.0, respectively. Both Fe3 + and Al3 + had obvious inhibitory effects on the enzyme. In contrast, Fe2 + could
obviously activate the enzyme, but other metal ions had a little impact.

Key words: Mucor petrinsularis, β-1,3-1,4 -glucanase, separation and purification, enzymatic properties