Saha Badal C, Cotta Michael A
Fermentation Biotechnology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, U.S. Department of Agriculture, Peoria, Illinois 61604, USA.
Biotechnol Prog. 2006 Mar-Apr;22(2):449-53. doi: 10.1021/bp050310r.
Wheat straw used in this study contained 44.24 +/- 0.28% cellulose and 25.23 +/- 0.11% hemicellulose. Alkaline H(2)O(2) pretreatment and enzymatic saccharification were evaluated for conversion of wheat straw cellulose and hemicellulose to fermentable sugars. The maximum yield of monomeric sugars from wheat straw (8.6%, w/v) by alkaline peroxide pretreatment (2.15% H(2)O(2), v/v; pH 11.5; 35 degrees C; 24 h) and enzymatic saccharification (45 degrees C, pH 5.0, 120 h) by three commercial enzyme preparations (cellulase, beta-glucosidase, and xylanase) using 0.16 mL of each enzyme preparation per g of straw was 672 +/- 4 mg/g (96.7% yield). During the pretreatment, no measurable quantities of furfural and hydroxymethyl furfural were produced. The concentration of ethanol (per L) from alkaline peroxide pretreated enzyme saccharified wheat straw (66.0 g) hydrolyzate by recombinant Escherichia coli strain FBR5 at pH 6.5 and 37 degrees C in 48 h was 18.9 +/- 0.9 g with a yield of 0.46 g per g of available sugars (0.29 g/g straw). The ethanol concentration (per L) was 15.1 +/- 0.1 g with a yield of 0.23 g/g of straw in the case of simultaneous saccharification and fermentation by the E. coli strain at pH 6.0 and 37 degrees C in 48 h.
本研究中使用的小麦秸秆含有44.24±0.28%的纤维素和25.23±0.11%的半纤维素。对碱性H₂O₂预处理和酶促糖化进行了评估，以将小麦秸秆纤维素和半纤维素转化为可发酵糖。通过碱性过氧化物预处理（2.15% H₂O₂，v/v；pH 11.5；35℃；24小时）和酶促糖化（45℃，pH 5.0，120小时），使用三种商业酶制剂（纤维素酶、β-葡萄糖苷酶和木聚糖酶），每克秸秆使用0.16 mL每种酶制剂，从小麦秸秆（8.6%，w/v）中获得的单糖最大产量为672±4 mg/g（产率96.7%）。在预处理过程中，未产生可测量量的糠醛和羟甲基糠醛。在pH 6.5和37℃下，重组大肠杆菌菌株FBR5在48小时内将碱性过氧化物预处理的酶糖化小麦秸秆（66.0 g）水解产物转化为乙醇的浓度（每升）为18.9±0.9 g，每克可利用糖的产率为0.46 g（每克秸秆0.29 g）。在pH 6.0和37℃下，大肠杆菌菌株在48小时内进行同步糖化和发酵时，乙醇浓度（每升）为15.1±0.1 g，每克秸秆的产率为0.23 g。
