A novel biochemical route for fuels and chemicals production from cellulosic biomass.
A novel biochemical route for fuels and chemicals production from cellulosic biomass.
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DOI：
10.1371/journal.pone.0031693
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发表时间：
2012
期刊：
影响因子：
3.7
通讯作者：
Xiong X
中科院分区：
文献类型：
--
作者：
Fan Z;Wu W;Hildebrand A;Kasuga T;Zhang R;Xiong X
以酶解为特征的常规生化平台包括五个关键步骤：预处理、纤维素酶生产、酶解、发酵和产物回收。糖是作为反应中间体生产的，用于随后发酵成燃料和化学品。在此，提出了一种替代的生物化学途径。预处理、酶水解和纤维素酶生产被合并到一个单一步骤中，称为合并的好氧处理，并且糖醛酸盐作为用于通过发酵生产生物燃料的反应性中间体而产生。在这项研究中，我们证明了巩固的酶水解和纤维素酶的生产步骤中的新途径，使用粗糙脉孢菌作为模型微生物和纤维素转化为乙醇作为模型系统的可行性。我们试图证明两个假设：1）纤维素可以通过减少β-葡萄糖苷酶的产生和通过增强纤维二糖脱氢酶的产生而被引导产生纤维二糖酸; 2）纤维二糖酸的两种水解产物-葡萄糖和琥珀酸-都可以用作乙醇和其他化学品生产的碳源。我们的研究结果表明，敲除多个拷贝的β-葡萄糖苷酶基因导致从纤维素生产纤维二糖酸，而不损害纤维素水解速率。通过添加外源性纤维二糖脱氢酶来模拟纤维二糖脱氢酶的过表达导致更多的纤维二糖酸盐生产。纤维二糖酸的两种水解产物：葡萄糖和葡萄糖酸盐都可以被大肠杆菌KO 11用于高效的乙醇生产。它们同时用于葡萄糖和葡萄糖酸盐共发酵。葡萄糖酸盐的使用速度甚至比葡萄糖更快。研究结果支持了这两个假设的可行性，为拟议的新路线奠定了基础。
The conventional biochemical platform featuring enzymatic hydrolysis involves five key steps: pretreatment, cellulase production, enzymatic hydrolysis, fermentation, and product recovery. Sugars are produced as reactive intermediates for subsequent fermentation to fuels and chemicals. Herein, an alternative biochemical route is proposed. Pretreatment, enzymatic hydrolysis and cellulase production is consolidated into one single step, referred to as consolidated aerobic processing, and sugar aldonates are produced as the reactive intermediates for biofuels production by fermentation. In this study, we demonstrate the viability of consolidation of the enzymatic hydrolysis and cellulase production steps in the new route using Neurospora crassa as the model microorganism and the conversion of cellulose to ethanol as the model system. We intended to prove the two hypotheses: 1) cellulose can be directed to produce cellobionate by reducing β-glucosidase production and by enhancing cellobiose dehydrogenase production; and 2) both of the two hydrolysis products of cellobionate—glucose and gluconate—can be used as carbon sources for ethanol and other chemical production. Our results showed that knocking out multiple copies of β-glucosidase genes led to cellobionate production from cellulose, without jeopardizing the cellulose hydrolysis rate. Simulating cellobiose dehydrogenase over-expression by addition of exogenous cellobiose dehydrogenase led to more cellobionate production. Both of the two hydrolysis products of cellobionate: glucose and gluconate can be used by Escherichia coli KO 11 for efficient ethanol production. They were utilized simultaneously in glucose and gluconate co-fermentation. Gluconate was used even faster than glucose. The results support the viability of the two hypotheses that lay the foundation for the proposed new route.
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影响因子：
4.4
作者：
OHTA, K;BEALL, DS;INGRAM, LO
通讯作者：
INGRAM, LO
影响因子：
3.5
作者：
ERIKSSON, KE;PETTERSSON, B;WESTERMARK, U
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WESTERMARK, U
影响因子：
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3.4
作者：
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作者：
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