CO2-H2O based pretreatment and enzyme hydrolysis of soybean hulls

Publication date: Available online 27 June 2017 Source:Enzyme and Microbial Technology Author(s): S.M. Mahfuzul Islam, Qian Li, Abdullah Al Loman, Lu-Kwang Ju The high carbohydrate content of soybean hull makes it an attractive biorefinery resource. But hydrolyzing its complex structure requires concerted enzyme activities, at least cellulase, xylanase, pectinase and α-galactosidase. Effective pretreatment that generates minimal inhibitory products is important to facilitate enzymatic hydrolysis. Combined CO2-H2O pretreatment and enzymatic hydrolysis by Aspergillus niger and Trichoderma reesei enzyme broths was studied here. The pretreatment was evaluated at 80°C–180°C temperature and 750psi–1800psi pressure, with fixed moisture content (66.7%) and pretreatment time (30min). Ground hulls without and with different pretreatments were hydrolyzed by enzyme at 50°C and pH 4.8 and compared for glucose, xylose, galactose, arabinose, mannose and total reducing sugar release. CO2-H2O pretreatment at 1250psi and 130°C was found to be optimal. Compared to the unpretreated hulls hydrolyzed with 2.5-fold more enzyme, this pretreatment improved glucose, xylose, galactose, arabinose and mannose releases by 55%, 35%, 105%, 683% and 52%, respectively. Conversions of 97% for glucose, 98% for xylose, 41% for galactose, 59% for arabinose, 87% for mannose and 89% for total reducing sugar were achieved with Spezyme CP at 18FPU/g hull. Monomerization of all carbohydrate types was de...
Source: Enzyme and Microbial Technology - Category: Biotechnology Source Type: research