Pectate lyases (Pels) can be used in the textile industrial process for cotton scouring and ramie degumming, and its hydrolyzed products oligo galacturonic acid, are high-value added agricultural and health products. In our previous studies, an alkaline pectate lyase PEL168 mutant, PEL3, was obtained with improved specific activity and thermostability. Here, a facile and rapid method for preparing an immobilized PEL3-inorganic hybrid nanoflower was developed, as it could improve its biocatalytic performance. With 0.02 mg/mL (112.2 U/mL) PEL3 in PBS buffer, five different divalent ions, including Mn2+, Ca2+, Co2+, Zn2+, and Cu2+, were used as inorganic component. The results showed that PEL3/Cu3(PO4)2 hybrid nanoflowers presented the highest relative activity with 2.5-fold increase, compared to the free PEL3. X-ray diffraction analysis confirmed that the composition of PEL3/Cu3(PO4)2 hybrid nanoflowers were pectate lyase PEL3 and Cu3(PO4)2⋅5H2O. The optimum temperature and pH of PEL3/Cu3(PO4)2 hybrid nanoflowers were ascertained to be 55°C and pH 9.0, respectively, exhibiting subtle difference from the free PEL3. However, the PEL3/Cu3(PO4)2 hybrid nanoflowers maintained 33% residual activity after 24 h incubation at 55°C, while the free PEL3 completely lost its activity after 18 h incubation at 55°C. Furthermore, over 50% residual activity of the PEL3/Cu3(PO4)2 hybrid nanoflowers was remained, even after four times of repetitive utilization, demonstrating its promising stability for practical application.
Keywords: enzyme immobilization; hybrid nanoflowers; pectate lyases; textile industry; thermostability.
Copyright © 2020 Wu, Luo, Lu, Zhan and Zhang.