High‐level expression of xyloglucanase B from Rhizomucor miehei and its application in the preparation of partially hydrolyzed apple pomace xyloglucan

Abstract

AbstractA xyloglucanase gene (RmXEG12B) was cloned from Rhizomucor miehei CAU432 and successfully expressed in Pichia pastoris. The highest xyloglucanase activity of 26,200 U/mL was achieved after 168 h high‐cell‐density fermentation. The optimal pH and temperature of RmXEG12B were 5.0 and 55°C, respectively. RmXEG12B showed good stability within pH of 3.0–10.0 and was stable up to 50°C. It exhibited the highest specific activity (5989.3 U/mg) towards tamarind xyloglucan. RmXEG12B hydrolyzed apple pomace xyloglucan to produce the partially hydrolyzed apple pomace xyloglucan, which demonstrated a weight average molecular weight of 1.6 × 104 Da and contained three major oligosaccharides with a degree of polymerization of 7–10. This is a strategy for the comprehensive utilization of apple pomace to produce the partially hydrolyzed apple pomace xyloglucan.