Optimization of the Cellulase−Ultrasonic Synergistic Extraction Conditions of Polysaccharides from Lenzites betulina

Abstract Lenzites betulina has been recognized as a rich source of chemical components, including polysaccharides, sterides and sugar alcohols. In this study, cellulase−ultrasonic synergistic extraction method was applied to extract polysaccharides from L. betulina , and the response surface methodology was used to optimize the extraction conditions. The eight basic factors affecting extraction yield were evaluated by Plackett−Burman design (PBD). Then, the four important factors significantly affecting the yield of polysaccharides from L. betulina , including enzymolysis temperature, enzymolysis time, ultrasound time and ultrasound temperature, were optimized by Box−Behnken design (BBD). Maximum extraction yield of L. betulina polysaccharides was 13.64±0.09 % at a cellulase dosage of 0.8 %, enzymolysis temperature of 60 °C, enzymolysis time of 180 min, pH of 4.5, liquid‐solid ratio of 45 ml/g, ultrasound power of 300 W, ultrasound time of 20 min and ultrasound temperature of 45 °C. Subsequently, the characteristic structure of crude polysaccharides was determined by FT‐IR. Results indicated that cellulase−ultrasonic synergistic treatment is suitable for L. betulina polysaccharides extraction, and it has good prospect for development and utilization.