Conversion of Lignocellulosic Biomass to Ethanol
Conversion of Lignocellulosic Biomass to Ethanol
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DOI：
10.1002/9781119771951.ch10
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发表时间：
2021-10
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影响因子：
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通讯作者：
Ramiya Baskaran;V. Natarajan;Shereena P. Joy;C. Krishnan
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文献类型：
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作者：
Ramiya Baskaran;V. Natarajan;Shereena P. Joy;C. Krishnan
利用木质纤维素生物质（LCB）生产纤维素乙醇是一种很有前途的生物燃料，利用生物催化剂通过生物化学途径生产纤维素乙醇已得到广泛的研究。LCB中的木质素-碳水化合物复合物（LCC）使其对生物催化剂的降解具有高度抗性。因此，LCB的热化学预处理被用来瓦解LCC结构，并促进纤维素酶对纤维素纤维的生物催化水解。有几种基于机械、水热和热化学处理的预处理方法。预处理的LCB随后被酶促水解成单糖并发酵成乙醇。非水解性溶解性多糖单加氧酶（LPMO）和扩张素样蛋白增强纤维素的酶促水解的效率。当LPMO氧化裂解糖苷键时，扩张素样蛋白质破坏结晶纤维素中的氢键，以使纤维素酶能够快速作用。异源木聚糖多糖是作物残渣等常规原料中的主要半纤维素。酶的混合物将木聚糖水解成木糖用于随后的发酵。基因工程微生物用于有效地将葡萄糖和木糖共发酵为乙醇。在高固体负载（HSL）下LCB的酶促水解以及葡萄糖和木糖的共发酵对于实现高乙醇浓度是重要的。本章介绍了LCB生产乙醇的生化处理的各个方面。
Cellulosic ethanol produced from lignocellulosic biomass (LCB) is a promising biofuel to reduce the use of petrol. The production of cellulosic ethanol through biochemical route using biocatalysts has been investigated widely. The lignin‐carbohydrate complex (LCC) in LCB makes it highly recalcitrant to degradation by biocatalysts. Hence, a thermochemical pretreatment of LCB is employed to disintegrate the LCC structure and facilitate cellulase's biocatalytic hydrolysis of cellulose fibers. There are several pretreatment methods based on mechanical, hydrothermal, and thermochemical treatments. The pretreated LCB is subsequently enzymatically hydrolyzed to simple sugars and fermented to ethanol. The non‐hydrolytic lytic polysaccharide monooxygenases (LPMO) and expansins like proteins enhance the efficiency of the enzymatic hydrolysis of cellulose. While LPMO oxidatively cleaves the glucosidic bonds, the expansin‐like proteins break the hydrogen bonds in the crystalline cellulose to enable rapid action of cellulases. The heterogeneous xylan polysaccharide is the major hemicellulose in conventional feedstocks like crop residues. A mixture of enzymes hydrolyze xylan to xylose for subsequent fermentation. Genetically engineered microbes are used to efficiently co‐ferment glucose and xylose to ethanol. The enzymatic hydrolysis of LCB at high solids loading (HSL) and co‐fermentation of glucose and xylose are important to achieve high ethanol concentration. This chapter describes various aspects of biochemical processing of LCB to produce ethanol.