Unraveling the genetic basis of xylose consumption in engineered Saccharomyces cerevisiae strains.
Unraveling the genetic basis of xylose consumption in engineered Saccharomyces cerevisiae strains.
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DOI：
10.1038/srep38676
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发表时间：
2016-12-21
影响因子：
4.6
通讯作者：
Pereira GA
中科院分区：
文献类型：
--
作者：
Dos Santos LV;Carazzolle MF;Nagamatsu ST;Sampaio NM;Almeida LD;Pirolla RA;Borelli G;Corrêa TL;Argueso JL;Pereira GA
开发能够发酵木糖（木质纤维素生物质中丰富的五碳糖）的生物催化剂是实现第二代乙醇可行生产的关键步骤。在这项工作中，通过添加戊糖代谢必需基因来修饰酿酒酵母的稳健工业菌株。随后，通过选择最佳木糖利用的适应性进化循环，菌株可以有效地将木糖转化为乙醇，产率为约0.46 g乙醇/g木糖。虽然独立进化，但两种菌株携带共同的突变：木糖异构酶基因的扩增和ISU 1的失活，ISU 1是一种编码参与铁硫簇组装的支架蛋白的基因。此外，其中一株进化株携带MAPKKK信号通路成员SSK 2的突变。在验证实验中，突变ISU 1或SSK 2提高了酵母细胞代谢木糖的能力，而没有适应性进化，这表明这些基因是木糖发酵调控网络中的关键参与者。此外，向生长培养基中添加铁离子改善了木糖发酵，即使是非进化细胞。我们的研究结果为C5-酵母的代谢工程提供了有前途的新目标，并指出铁作为一种潜在的新添加剂，用于改善第二代乙醇生产。
The development of biocatalysts capable of fermenting xylose, a five-carbon sugar abundant in lignocellulosic biomass, is a key step to achieve a viable production of second-generation ethanol. In this work, a robust industrial strain of Saccharomyces cerevisiae was modified by the addition of essential genes for pentose metabolism. Subsequently, taken through cycles of adaptive evolution with selection for optimal xylose utilization, strains could efficiently convert xylose to ethanol with a yield of about 0.46 g ethanol/g xylose. Though evolved independently, two strains carried shared mutations: amplification of the xylose isomerase gene and inactivation of ISU1, a gene encoding a scaffold protein involved in the assembly of iron-sulfur clusters. In addition, one of evolved strains carried a mutation in SSK2, a member of MAPKKK signaling pathway. In validation experiments, mutating ISU1 or SSK2 improved the ability to metabolize xylose of yeast cells without adaptive evolution, suggesting that these genes are key players in a regulatory network for xylose fermentation. Furthermore, addition of iron ion to the growth media improved xylose fermentation even by non-evolved cells. Our results provide promising new targets for metabolic engineering of C5-yeasts and point to iron as a potential new additive for improvement of second-generation ethanol production.
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影响因子：
14.8
作者：
Gietz, R. Daniel;Schiestl, Robert H.
通讯作者：
Schiestl, Robert H.
影响因子：
6.3
作者：
Hector RE;Dien BS;Cotta MA;Mertens JA
通讯作者：
Mertens JA
影响因子：
48
作者：
Gibson, Daniel G.;Young, Lei;Smith, Hamilton O.
通讯作者：
Smith, Hamilton O.
影响因子：
3.7
作者：
Delobel, Pierre;Tesniere, Catherine
通讯作者：
Tesniere, Catherine
影响因子：
4.2
作者：
Kaba, Hani E. J.;Nimtz, Manfred;Bilitewski, Ursula
通讯作者：
Bilitewski, Ursula