木质生物资源的水解

水解是利用木质生物资源以生物转化法制取乙醇的重要步骤,水解技术主要包括稀酸水解、浓酸水解和酶水解。酶水解的特点是具有选择性,降解产物少,葡萄糖得率高,能耗较低,不要求反应器具有高耐腐蚀性,被视为最有潜力降低乙醇生产成本的突破口。目前,利用木质生物资源制取乙醇还没有进入工业化生产。其原因在于成本高于利用淀粉和糖料,原料的预处理成本高、纤维素酶的生产成本高、酶活力低、纤维素的酶水解效率低、酶用量大、对半纤维素的有效利用不够。因此,需要研发有效的预处理工艺,提高纤维素底物的生物酶可及度;筛选高效纤维素酶、优化酶水解工艺,提高纤维素的水解率;利用基因重组的发酵性微生物,把戊糖发酵成乙醇,提高乙醇的产量,降低生产成本。

Hydrolysis of Woody Biomass

Hydrolysis is an important step for bioconversion of woody biomass to ethanol.Hydrolysis technology includes dilute acid hydrolysis,concentrated acid hydrolysis and enzymatic hydrolysis.Featured as selective attack,less degradation product,high recovery of glucose,low energy consumption,no demand on anti-corrosive reactor,enzymatic hydrolysis has been regarded as the potential breakthrough to lower the cost of ethanol production.Currently the cost of bioconversion of biomass to ethanol is higher than those of starch and sugar due to high cost of raw material pretreatment,expensive cellulase production,low cellulase activity,low efficiency of enzymatic hydrolysis,high cellulase loading and insufficient utilization of hemicellulose.Therefore,(effective) pretreatment technology should be developed to improve enzymatic digestibility of(cellulose),selection of high-efficient cellulase and optimization of enzymatic hydrolysis should be conducted to raise the rate of enzymatic hydrolysis.Conversion of(5-carbon) sugars into ethanol by means of genetically engineered microorganisms should be conducted to raise ethanol production.