Engineering yeast with bifunctional minicellulosome and cellodextrin pathway for co-utilization of cellulose-mixed sugars.
Engineering yeast with bifunctional minicellulosome and cellodextrin pathway for co-utilization of cellulose-mixed sugars.
复制标题
具有双功能微纤维素体和纤维糊精途径的工程酵母用于纤维素混合糖的共同利用
DOI：
10.1186/s13068-016-0554-6
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发表时间：
2016
影响因子：
6.3
通讯作者：
Tan TW
中科院分区：
文献类型：
--
作者：
Fan LH;Zhang ZJ;Mei S;Lu YY;Li M;Wang ZY;Yang JG;Yang ST;Tan TW
背景联合生物处理(CBP)将纤维素酶生产、纤维素糖化和发酵整合为一步，已被广泛认为是生产第二代燃料乙醇的最终低成本配置。然而，对微生物菌株的需求限制了CBP的应用。结果在本工作中，通过异源纤维糊精利用途径和双功能微纤维素体工程酿酒酵母获得了纤维分解酵母。细胞展示的微小纤维素体是由两个支架蛋白衍生的，含有一个内切葡聚糖酶和一个外切葡聚糖酶，而胞内的纤维糊精途径由一个纤维糊精转运体和一个β-葡萄糖苷酶组成，它模拟了热梭状芽胞杆菌独特的纤维素利用系统。在没有葡萄糖抑制/抑制纤维素酶和混合糖吸收的情况下，啤酒降解和利用纤维素。因此，只需少量接种非诱导酵母细胞，就能在一步共发酵过程中有效地将纤维素和半乳糖共同转化为乙醇，从羧甲基纤维素获得了~62.61 mg纤维素乙醇/g cell·h的高比产率，从磷酸膨胀纤维素获得了~56.37 mg纤维素乙醇/g cell·h的高比产率。这项工作的成果可能会进一步促进纤维素生物燃料的生产。
BackgroundConsolidated bioprocessing (CBP), integrating cellulase production, cellulose saccharification, and fermentation into one step has been widely considered as the ultimate low-cost configuration for producing second-generation fuel ethanol. However, the requirement of a microbial strain able to hydrolyze cellulosic biomass and convert the resulting sugars into high-titer ethanol limits CBP application.ResultsIn this work, cellulolytic yeasts were developed by engineeringSaccharomyces cerevisiaewith a heterologous cellodextrin utilization pathway and bifunctional minicellulosomes. The cell-displayed minicellulosome was two-scaffoldin derived, and contained an endoglucanase and an exoglucanase, while the intracellular cellodextrin pathway consisted of a cellodextrin transporter and a β-glucosidase, which mimicked the unique cellulose-utilization system inClostridium thermocellumand allowedS. cerevisiaeto degrade and use cellulose without glucose inhibition/repression on cellulases and mixed-sugar uptake. Consequently, only a small inoculation of the non-induced yeast cells was required to efficiently co-convert both cellulose and galactose to ethanol in a single-step co-fermentation process, achieving a high specific productivity of ~62.61 mg cellulosic ethanol/g cell·h from carboxymethyl cellulose and ~56.37 mg cellulosic ethanol/g cell·h from phosphoric acid-swollen cellulose.ConclusionsOur work provides a versatile engineering strategy for co-conversion of cellulose-mixed sugars to ethanol byS. cerevisiae, and the achievements in this work may further promote cellulosic biofuel production.