Enhanced enzymatic hydrolysis of lignocellulose by optimizing enzyme complexes.
To enhance the conversion of the cellulose and hemicellulose, the corncob pretreated by aqueous ammonia soaking was hydrolyzed by enzyme complexes. The saturation limit for cellulase (Spezyme CP) was determined as 15 mg protein/g glucan (50 filter paper unit (FPU)/g glucan). The accessory enzymes (beta-glucosidase, xylanase, and pectinase) were supplemented to hydrolyze cellobiose (cellulase-inhibiting product), hemicellulose, and pectin (the component covering the fiber surfaces), respectively. It was found that beta-glucosidase (Novozyme 188) loading of 1.45 mg protein/g glucan [30 cellobiase units (CBU)/g glucan] was enough to eliminate the cellobiose inhibitor, and 2.9 mg protein/g glucan (60 CBU/g glucan) was the saturation limit. The supplementation of xylanase and pectinase can increase the conversion of cellulose and hemicellulose significantly. The yields of glucose and xylose enhanced with the increasing enzyme loading, but the increasing trend became low at high loading. Compared with xylanase, pectinase was more effective to promote the hydrolysis of cellulose and hemicellulose. The supplementation of pectinase with 0.12 mg protein/g glucan could increase the yields of glucose and xylose by 7.5% and 29.3%, respectively.
Zhang
Mingjia
M
State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, 92 Weijin Road, Nankai District, Tianjin 300072, China.
Su
Rongxin
R
Qi
Wei
W
He
Zhimin
Z
D002475:Cellobiose / Q000378:metabolism; D002480:Cellulase / Q000378:metabolism; D043364:Endo-1,4-beta Xylanases / Q000378:metabolism; D004798:Enzymes / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D006868:Hydrolysis; D008031:Lignin / Q000378:metabolism*; D011096:Polygalacturonase / Q000378:metabolism; D013379:Substrate Specificity; D014994:Xylose / Q000378:metabolism; D003313:Zea mays / Q000378:metabolism; D001617:beta-Glucosidase / Q000378:metabolism
D004798:Enzymes; C036909:lignocellulose; D002475:Cellobiose; D008031:Lignin; D014994:Xylose; D011096:Polygalacturonase; D001617:beta-Glucosidase; D002480:Cellulase; D043364:Endo-1,4-beta Xylanases; D005947:Glucose