Comparison of pretreatment strategies for enzymatic saccharification and fermentation of barley straw to ethanol
Comparison of pretreatment strategies for enzymatic saccharification and fermentation of barley straw to ethanol
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DOI：
10.1016/j.nbt.2009.10.005
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发表时间：
2010-02-28
影响因子：
5.4
通讯作者：
Cotta, Michael A.
中科院分区：
文献类型：
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作者：
Saha, Badal C.;Cotta, Michael A.
本研究中使用的大麦秸秆含有34.3%的纤维素，23.0%的半纤维素和13.3%的木质素（水分，6.5%）。几种预处理（稀酸，石灰和碱性过氧化物）和酶糖化程序进行了评价转化为单糖的大麦草。糖的最大释放量（葡萄糖，384 mg;木糖，187 mg;阿拉伯糖，32 mg;总糖，604 mg/g;最大理论糖产量的94%）（10%，w/v）通过碱性过氧化氢获得（2.5%H2O2，pH 11.5）预处理（35 ℃，24小时）和酶糖化（45 ℃，pH5.0，120小时），稀释2倍后加入三种商业酶制剂的混合物（纤维素酶、β-葡糖苷酶和半纤维素酶），每种酶的剂量水平为0.15 μ g稻草。稀酸和石灰预处理，然后酶糖化产生566毫克（88%产率）和582毫克（91%产率）总糖/克的大麦秆，分别。利用混合糖的重组大肠杆菌菌株FBR 5在17小时内从稀酸预处理和酶糖化的大麦杆水解物（23.7g糖/L）的乙醇产率为11.4g/L（0.48g/g有效糖，0.26g/g麦杆）。从石灰和碱性过氧化物预处理的大麦秆获得的24.4和26.2 g糖/L的乙醇产率分别为11.4和11.9 g/L。在所用条件下，三种预处理均未抑制发酵。
Barley straw used in this study contained 34.3% cellulose, 23.0% hemicellulose and 13.3% lignin (moisture, 6.5%). Several pretreatments (dilute acid, lime and alkaline peroxide) and enzymatic saccharification procedures were evaluated for the conversion of barley straw to monomeric sugars. The maximum release of sugars (glucose, 384 mg; xylose, 187 mg; arabinose, 32 mg; total sugars, 604 mg/g; 94% of maximum theoretical sugar yield) from barley straw (10%, w/v) was obtained by alkaline peroxide (2.5% H2O2, pH 11.5) pretreatment (35 degrees C, 24 hours) and enzymatic saccharification (45 degrees C, pH 5.0, 120 hours) after diluting 2 times before adding a cocktail of three commercial enzyme preparations (cellulase, beta-glucosidase and hemicellulase) each at the dose level of 0.15 mug of straw. Dilute acid and lime pretreatments followed by enzymatic saccharification generated 566 mg (88% yield) and 582 mg (91% yield) total sugars/g of barley straw, respectively. The yield of ethanol from the dilute acid pretreated and enzymatically saccharified barley straw hydrolyzate (23.7 g sugars/L) was 11.4 g/L (0.48 g/g available sugars, 0.26 g/g straw) by the mixed sugar utilizing recombinant Escherichia coli strain FBR5 in 17 hours. The ethanol yields were 11.4 and 11.9 g/L from 24.4 and 26.2 g sugars/L obtained from lime and alkaline peroxide pretreated barley straw, respectively. No inhibition of fermentation occurred by any of the three pretreatments under the conditions used.