Growth and fermentation of D-xylose by Saccharomyces cerevisiae expressing a novel D-xylose isomerase originating from the bacterium Prevotella ruminicola TC2-24.
Growth and fermentation of D-xylose by Saccharomyces cerevisiae expressing a novel D-xylose isomerase originating from the bacterium Prevotella ruminicola TC2-24.
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DOI：
10.1186/1754-6834-6-84
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发表时间：
2013-05-30
影响因子：
6.3
通讯作者：
Mertens JA
中科院分区：
文献类型：
--
作者：
Hector RE;Dien BS;Cotta MA;Mertens JA
表达D-木糖异构酶(XI)的酿酒酵母菌株从D-木糖生产乙醇的产量是已报道的最高的。不幸的是，在酿酒酵母中表达的大多数细菌XI要么没有功能，需要额外的菌株修饰，要么对D-木糖亲和力低。本研究分析了瘤胃和肠道微生物中的几种XI，以确定具有改良性质的酶用于D-木糖发酵的酿酒酵母。从一株酿酒酵母CEN.PK2-1C中分离到4个来源于瘤胃和肠道细菌的XI，并在其天然D-木糖代谢的亲本菌株PK2-1C中高效表达。根据菌株在D-木糖介质中的生长能力，其中三个XIs在酿酒酵母中具有功能。从瘤胃普雷沃特拉菌TC2-24中筛选出一株最有希望表达XI的菌株，通过D-木糖在好氧和微氧条件下的连续转移，使其进一步适应于好氧和发酵生长。该进化菌株在D-木糖培养基上的比生长速率为0.23h-1，与已报道的酿酒酵母相似菌株(包括表达Piromyces sp的菌株)的生长速度相当。E2 XI.利用该菌株发酵D-木糖，91h产乙醇13.6g/L，代谢率为理论值的83%。通过对该酶的分析，确定了该酶的Vmax为0.81Mole/μ/mg蛋白，Km值为34 mm。本研究从瘤胃细菌Prevoella rumicola TC2-24中鉴定出一种新的木糖异构酶，与在酵母中表达的其他细菌和真菌的D-木糖异构酶相比，它具有最高的亲和力和比活性之一。当在酿酒酵母中表达并用于发酵D-木糖时，可获得很高的乙醇产量。这一新的XI应该是构建其他D-木糖发酵菌株的一个有前途的资源，包括工业酵母的遗传背景。
Saccharomyces cerevisiae strains expressing D-xylose isomerase (XI) produce some of the highest reported ethanol yields from D-xylose. Unfortunately, most bacterial XIs that have been expressed in S. cerevisiae are either not functional, require additional strain modification, or have low affinity for D-xylose. This study analyzed several XIs from rumen and intestinal microorganisms to identify enzymes with improved properties for engineering S. cerevisiae for D-xylose fermentation. Four XIs originating from rumen and intestinal bacteria were isolated and expressed in a S. cerevisiae CEN.PK2-1C parental strain primed for D-xylose metabolism by over expression of its native D-xylulokinase. Three of the XIs were functional in S. cerevisiae, based on the strain’s ability to grow in D-xylose medium. The most promising strain, expressing the XI mined from Prevotella ruminicola TC2-24, was further adapted for aerobic and fermentative growth by serial transfers of D-xylose cultures under aerobic, and followed by microaerobic conditions. The evolved strain had a specific growth rate of 0.23 h-1 on D-xylose medium, which is comparable to the best reported results for analogous S. cerevisiae strains including those expressing the Piromyces sp. E2 XI. When used to ferment D-xylose, the adapted strain produced 13.6 g/L ethanol in 91 h with a metabolic yield of 83% of theoretical. From analysis of the P. ruminicola XI, it was determined the enzyme possessed a Vmax of 0.81 μmole/min/mg protein and a Km of 34 mM. This study identifies a new xylose isomerase from the rumen bacterium Prevotella ruminicola TC2-24 that has one of the highest affinities and specific activities compared to other bacterial and fungal D-xylose isomerases expressed in yeast. When expressed in S. cerevisiae and used to ferment D-xylose, very high ethanol yield was obtained. This new XI should be a promising resource for constructing other D-xylose fermenting strains, including industrial yeast genetic backgrounds.
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影响因子：
3.6
作者：
Ma, Menggen;Liu, Z. Lewis;Moon, Jaewoong
通讯作者：
Moon, Jaewoong
影响因子：
3.6
作者：
Dodd D;Mackie RI;Cann IK
通讯作者：
Cann IK
影响因子：
4.4
作者：
Lee, Sun-Mi;Jellison, Taylor;Alper, Hal S.
通讯作者：
Alper, Hal S.
影响因子：
3.8
作者：
Jeppsson, M;Bengtsson, O;Gorwa-Grauslund, MF
通讯作者：
Gorwa-Grauslund, MF
DOI：
10.1099/00207713-47-2-284
发表时间：
1997-04-01
期刊：
INTERNATIONAL JOURNAL OF SYSTEMATIC BACTERIOLOGY
影响因子：
--
作者：
Avgustin, G;Wallace, RJ;Flint, HJ
通讯作者：
Flint, HJ