Studies on Character of a Chitinase ChiC from Aeromonas veronii B565 and its Synergism with Chitin Binding Protein.

To investigate the characteristics of low activity ChiC from A. veronii B565 and break the bottleneck of its application, this experiment established a recombined ChiC pichia engineering bacteria GS115/PIC9-ChiC, carried out methanol induction expression and purification, and studied its basic enzymology properties. The result indicated that ChiC was expressed in P. pastoris with a yield of 232.6 mg/L after 48 h methanol induction. The purified ChiC showed optimal specific activity of 7.6 U/mg at pH 8.0 and 40°C. ChiC had broad adaptability for pH and temperature. It retained over 80% optimal activity at pH 3.0~10.0 at 40°C or the temperature 0~40°C at pH 7.0. The chitin binding protein CBP21 from Serratia marcescens GIM1.217 was expressed in E. Coli. The affinity of CBP21 for shrimp shell chitin and colloidal chitin were different, the chitinase activity of ChiC was increased significantly from 2 (colloidal chitin as substrate) to 9 (shrimp shell chitin as substrate) fold, when acted synergistically with CBP21. This study laid a theoretical foundation for further slurrying chitinase gene, and provided a possible solution for breaking the bottleneck of this low enzyme activity of chitinase application. [ABSTRACT FROM AUTHOR]