Immobilization of β-1,3-xylanase on pitch-based hyper-crosslinked polymers loaded with Ni for algal biomass manipulation.

β-1,3-xylanase plays an important role in the conversion of algal biomass into renewable chemical commodities and functional xylooligosaccharides. Efficient immobilization of the target enzymes that could integrate the separation, purification, and immobilization in one-step may have great potentials. The cheap and easily obtained pitch was adopted as the raw material to prepare the hyper-cross-linked polymers with the specific surface areas of 560 m/g and the Ni loading about 80 mg/g. As a carrier, it could immobilize and purify the β-1,3-xylanases directly from the crude cell debris with the activity recovery of (80.66 ± 0.87) %. The half-life of the immobilized β-1,3-xylanases was 50 min at 50 °C, which was significantly longer than the free ones with only 14 min. The immobilized β-1,3-xylanases could retain 65 % of the activity after stored at 30 ℃ for 80 h, they could also retain 87 % of the original activity after 15 cycles of reuse. In terms of potential applications in the manipulation of algae Caulerpa lentillifera, the immobilized β-1,3-xylanases could release 30 % more reducing sugar in 85 h. The method proposed here is promising for algal biomass manipulation because of its low cost, stable storage, convenient recycling and excellent reusability.