Enhancement of Catalytic Performance of α-dextranase from Chaetomium gracile Through Optimization and Suitable Shear Force
2018
Zhang, Zedong | Liu, Jidong | Ma, Shaoying | Lü, Haiqin | Hang, Fangxue | Huang, Peng | Li, Kai
Dextran causes negative impact on the normal production of sugar industry. Traditional removal methods have many disadvantages. 6-alpha-D-glucan-6-glucanohydrolase (EC 3.2.1.11) from Chaetomium gracile without food safety concern could remove dextran, but it has low level of enzyme production. The present study aimed to improve α-dextranase activity to meet industry demand. Consequently, α-dextranase activity reached 242.8 U/mL when fermentation condition was 29 °C, pH 6.0 and 220 rpm. Meanwhile, ten glass beads were added to fermentation medium when fermentation time was 12 h, which improved enzyme activity by 135.5% with the highest activity. Purified α-dextranase exhibited excellent thermal stability and surfactants tolerance. α-Dextranase from C. gracile could remove dextran by 46.6% in mixed sugarcane juice and 14.1% in clarified sugarcane juice. It had similar dextran removal efficiency with commercial enzymes. These evaluations showed that α-dextranase had great potential in removing dextran in sugar industry.
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