Yield-determining factors in high-solids enzymatic hydrolysis of lignocellulose.
Yield-determining factors in high-solids enzymatic hydrolysis of lignocellulose.
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DOI：
10.1186/1754-6834-2-11
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发表时间：
2009-06-08
影响因子：
6.3
通讯作者：
Jørgensen H
中科院分区：
文献类型：
--
作者：
Kristensen JB;Felby C;Jørgensen H
在高固体（底物）浓度下工作在木质纤维素生物质的酶促转化中是有利的，因为它增加了产物浓度和植物生产率，同时降低了能量和水输入。然而，对于许多木质纤维素底物，已经表明，在增加底物浓度时，相应的产率以目前的模型和酶-底物相互作用的知识无法解释的方式降低。产率的这种降低是不希望的，因为它抵消了在高固体含量下工作的优点。“固体效应”的原因至今仍不清楚。发现在增加固体浓度时转化率降低是一种通用或内在效应，描述了从5至30%初始总固体含量（w/w）的线性相关性。先前已经证明，不充分的混合与该效应无关。滤纸水解实验表明，无论是木质素含量，也不是半纤维素衍生的抑制剂似乎是负责产量下降。在高固体负载下，葡萄糖和特别是纤维二糖（和同时糖化和发酵中的乙醇）在增加的浓度下的产物抑制起作用，但不能完全解释转化率的降低。纤维素酶的吸附被发现在增加固体浓度降低。在降低的吸附和转化率之间存在强相关性，表明纤维素酶对纤维素的吸附的抑制导致产率降低。水解产物对酶吸附的抑制似乎是在纤维素生物质的酶促分解中增加底物浓度时产率降低的主要原因。为了促进在高固体浓度下的高转化率，必须提高对高固体产物抑制和吸附抑制机制的理解。
Working at high solids (substrate) concentrations is advantageous in enzymatic conversion of lignocellulosic biomass as it increases product concentrations and plant productivity while lowering energy and water input. However, for a number of lignocellulosic substrates it has been shown that at increasing substrate concentration, the corresponding yield decreases in a fashion which can not be explained by current models and knowledge of enzyme-substrate interactions. This decrease in yield is undesirable as it offsets the advantages of working at high solids levels. The cause of the 'solids effect' has so far remained unknown. The decreasing conversion at increasing solids concentrations was found to be a generic or intrinsic effect, describing a linear correlation from 5 to 30% initial total solids content (w/w). Insufficient mixing has previously been shown not to be involved in the effect. Hydrolysis experiments with filter paper showed that neither lignin content nor hemicellulose-derived inhibitors appear to be responsible for the decrease in yields. Product inhibition by glucose and in particular cellobiose (and ethanol in simultaneous saccharification and fermentation) at the increased concentrations at high solids loading plays a role but could not completely account for the decreasing conversion. Adsorption of cellulases was found to decrease at increasing solids concentrations. There was a strong correlation between the decreasing adsorption and conversion, indicating that the inhibition of cellulase adsorption to cellulose is causing the decrease in yield. Inhibition of enzyme adsorption by hydrolysis products appear to be the main cause of the decreasing yields at increasing substrate concentrations in the enzymatic decomposition of cellulosic biomass. In order to facilitate high conversions at high solids concentrations, understanding of the mechanisms involved in high-solids product inhibition and adsorption inhibition must be improved.
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影响因子：
5.7
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影响因子：
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