Direct ethanol production from cellulosic materials using a diploid strain of Saccharomyces cerevisiae with optimized cellulase expression.
Direct ethanol production from cellulosic materials using a diploid strain of Saccharomyces cerevisiae with optimized cellulase expression.
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DOI：
10.1186/1754-6834-4-8
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发表时间：
2011-04-15
影响因子：
6.3
通讯作者：
Kondo A
中科院分区：
文献类型：
--
作者：
Yamada R;Taniguchi N;Tanaka T;Ogino C;Fukuda H;Kondo A
纤维素的水解需要纤维素水解酶内切葡聚糖酶、纤维素生物水解酶和β-葡萄糖苷酶的作用。这些酶的表达比例和协同作用显著影响纤维素降解的程度和特定速率。在这项研究中，我们利用我们之前开发的优化酵母中纤维素酶表达水平的方法，构建了一个二倍体的酿酒酵母菌株，优化了纤维素酶的表达，并试图提高纤维素降解活性，使秸秆直接生产乙醇成为可能，这是木质纤维素生物质最丰富的来源之一。在糖蜜培养基（381.4 mU/g湿细胞）中预培养的工程二倍体菌株显示出比亲本单倍体菌株（63.5 mU/g湿细胞）高约6倍的磷酸肿胀纤维素（PASC）降解活性。二倍体菌株用于发酵PASC时，72小时内乙醇产量为7.6 g/l，乙醇产量达到理论值的75%，预处理后的稻秆在72小时内乙醇产量为7.5 g/l。我们开发了一种优化表达纤维素水解酶的二倍体酵母菌株，使其能够直接从纤维素材料中发酵。虽然这是一项概念验证研究，但据我们所知，这是第一个使用表达纤维素酶的酵母在不添加外源酶的情况下从农业废物生物质中生产乙醇的报告。我们的研究结果表明，将酵母的多基因表达优化和二倍体化结合起来是一种很有前途的方法，可以提高不同类型木质纤维素生物质的乙醇产量。
Hydrolysis of cellulose requires the action of the cellulolytic enzymes endoglucanase, cellobiohydrolase and β-glucosidase. The expression ratios and synergetic effects of these enzymes significantly influence the extent and specific rate of cellulose degradation. In this study, using our previously developed method to optimize cellulase-expression levels in yeast, we constructed a diploid Saccharomyces cerevisiae strain optimized for expression of cellulolytic enzymes, and attempted to improve the cellulose-degradation activity and enable direct ethanol production from rice straw, one of the most abundant sources of lignocellulosic biomass. The engineered diploid strain, which contained multiple copies of three cellulase genes integrated into its genome, was precultured in molasses medium (381.4 mU/g wet cell), and displayed approximately six-fold higher phosphoric acid swollen cellulose (PASC) degradation activity than the parent haploid strain (63.5 mU/g wet cell). When used to ferment PASC, the diploid strain produced 7.6 g/l ethanol in 72 hours, with an ethanol yield that achieved 75% of the theoretical value, and also produced 7.5 g/l ethanol from pretreated rice straw in 72 hours. We have developed diploid yeast strain optimized for expression of cellulolytic enzymes, which is capable of directly fermenting from cellulosic materials. Although this is a proof-of-concept study, it is to our knowledge, the first report of ethanol production from agricultural waste biomass using cellulolytic enzyme-expressing yeast without the addition of exogenous enzymes. Our results suggest that combining multigene expression optimization and diploidization in yeast is a promising approach for enhancing ethanol production from various types of lignocellulosic biomass.
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影响因子：
4.1
作者：
Kim, MD;Rhee, SK;Seo, JH
通讯作者：
Seo, JH
影响因子：
3.4
作者：
Yamada, Ryosuke;Yamakawa, Syun-ichi;Kondo, Akihiko
通讯作者：
Kondo, Akihiko
影响因子：
5
作者：
Kadam, KL;Newman, MM
通讯作者：
Newman, MM
影响因子：
8.4
作者：
Den Haan, Riaan;Rose, Shaunita H.;van Zyl, Willem H.
通讯作者：
van Zyl, Willem H.
影响因子：
2.8
作者：
Lee, TH;Aoki, H;Shoda, M
通讯作者：
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