Polyacrylamide hydrogel carrier (matrix-type macrogel beads): Improvement in the catalytic behavior, stability, and reusability of industrially valuable xylanase from a thermophile Geobacillus stearothermophilus

Abstract

The solid macrogel beads composed of the polyacrylamide hydrogel matrix are widely opted to use in various bioengineering applications because of chemically inert and electrically neutral behavior. In the current study, biocompatibility and the robust nature of the insoluble polyacrylamide matrix-based macrogel beads were successfully analyzed and proved to be an efficient carrier matrix with 59% immobilization yield of xylanase. Immobilized xylanase indicated remarkable catalytic properties and stability profile with reference to its soluble counterpart. The optimum reaction temperature and pH of immobilized enzyme remained same at 50 °C and 7.0, respectively; however, the catalysis period shifted to 15 min. as related to soluble enzyme (5 min.). The diffusional hindrance of the large molecular mass xylan from the corncob source created a decline in Vmax of immobilized enzyme from 4772.5 to 451.3 U min−1; however, the Km value increased from 0.507 to 0.76 mg min−1 with reference to its soluble counterpart. Immobilized xylanase showed its striking tolerance capability against high temperatures as compared to its soluble part and retained 52% activity at 60 °C after 120 min. About 32% activity of immobilized xylanase attained at 70 °C even after 60 min. Immobilized xylanase within macrogel beads also exhibited good recycling efficiency by retaining 24% activity after 6 consecutive catalytic rotations and revealed its capability to be used as a plausible candidate to proceed various industrial bioprocesses.

Keywords

• Polyacrylamide matrix
• Xylanase
• Immobilization
• Biodegradation
• Thermal stability
• Reusability