Industrial attributes of p-glucanase produced by Bacillus sp. CSB55 and its potential application as bio-industrial catalyst

摘要

The beta-glucanase produced from Bacillus sp. CSB55 not only depicts the potent industrial characteristics but also relates as bio-industrial catalyst supporting the spontaneous formation of the products, high hydrolytic efficiency, and feasibility of the enzymatic reaction. A homogeneous beta-glucanase (GluB55) was purified via various purification processes resulting in 11.69% yield and 14.24-fold purity. Biochemical characterization of the purified enzyme revealed the molecular mass of approximately 40 kDa, which was verified by zymography. The optimum activity of GluB55 was determined at pH 7.2 and 55 degrees C. GluB55 could highly hydrolyze carboxymethylcellulose and was stable over a wide range of pH, retaining more than 70% residual activity at pH 5.8-11.0 and carried 100% thermostability as high as 60 degrees C. In addition, it showed 68% residual activity at 70 degrees C. The N-terminal amino acid sequence of GluB55 was Ala-Asn-Pro-Glu-Leu-Val-Asn-X-Gln-Ala-X-X-Ala-X-Gln-Gly. The enzyme activity was stimulated by Co2+ (158.6%), Zn2+ (211.1%), Mn2+ (264.4%), and Ba2+ (211.4%). Enzyme kinetics showed K-m and V-max values of 0.022 mg mL(-1) and 994.56 +/- 3.72 U mg(-1), respectively. Q(10) was calculated to be 1.12. increment H, increment G, and increment S were low revealing that the formation of the transition phase and conversion to the product is very well organized. The lower the free energy change ( increment G), the more feasible is the reaction.