A genome shuffling-generated <i>Saccharomyces cerevisiae</i> isolate that ferments xylose and glucose to produce high levels of ethanol

Ge, Jingping; Sun, Haijie; Song, Gang; Ling, Hongzhi; Ping, Wenxiang

doi:10.1007/s10295-011-1076-7

Cited by 23 publications

(9 citation statements)

References 25 publications

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“…In addition, genome shuffling has also been used in combination with metabolic engineering and evolutionary adaptation, for improving D-xylose utilization capacity in different S. cerevisiae strains [56,57]. In the present paper, we successfully exploited a combinatorial approach using all three random strain improvement strategies described above, in order to improve D-xylose fermentation efficiency of the recombinant industrial strain HDY.GUF5.…”

Section: Discussionmentioning

confidence: 99%

Development of a D-xylose fermenting and inhibitor tolerant industrial Saccharomyces cerevisiae strain with high performance in lignocellulose hydrolysates using metabolic and evolutionary engineering

Demeke

Dietz

et al. 2013

Biotechnol Biofuels

272

213

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BackgroundThe production of bioethanol from lignocellulose hydrolysates requires a robust, D-xylose-fermenting and inhibitor-tolerant microorganism as catalyst. The purpose of the present work was to develop such a strain from a prime industrial yeast strain, Ethanol Red, used for bioethanol production.ResultsAn expression cassette containing 13 genes including Clostridium phytofermentans XylA, encoding D-xylose isomerase (XI), and enzymes of the pentose phosphate pathway was inserted in two copies in the genome of Ethanol Red. Subsequent EMS mutagenesis, genome shuffling and selection in D-xylose-enriched lignocellulose hydrolysate, followed by multiple rounds of evolutionary engineering in complex medium with D-xylose, gradually established efficient D-xylose fermentation. The best-performing strain, GS1.11-26, showed a maximum specific D-xylose consumption rate of 1.1 g/g DW/h in synthetic medium, with complete attenuation of 35 g/L D-xylose in about 17 h. In separate hydrolysis and fermentation of lignocellulose hydrolysates of Arundo donax (giant reed), spruce and a wheat straw/hay mixture, the maximum specific D-xylose consumption rate was 0.36, 0.23 and 1.1 g/g DW inoculum/h, and the final ethanol titer was 4.2, 3.9 and 5.8% (v/v), respectively. In simultaneous saccharification and fermentation of Arundo hydrolysate, GS1.11-26 produced 32% more ethanol than the parent strain Ethanol Red, due to efficient D-xylose utilization. The high D-xylose fermentation capacity was stable after extended growth in glucose. Cell extracts of strain GS1.11-26 displayed 17-fold higher XI activity compared to the parent strain, but overexpression of XI alone was not enough to establish D-xylose fermentation. The high D-xylose consumption rate was due to synergistic interaction between the high XI activity and one or more mutations in the genome. The GS1.11-26 had a partial respiratory defect causing a reduced aerobic growth rate.ConclusionsAn industrial yeast strain for bioethanol production with lignocellulose hydrolysates has been developed in the genetic background of a strain widely used for commercial bioethanol production. The strain uses glucose and D-xylose with high consumption rates and partial cofermentation in various lignocellulose hydrolysates with very high ethanol yield. The GS1.11-26 strain shows highly promising potential for further development of an all-round robust yeast strain for efficient fermentation of various lignocellulose hydrolysates.

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Section: Discussionmentioning

confidence: 99%

Development of a D-xylose fermenting and inhibitor tolerant industrial Saccharomyces cerevisiae strain with high performance in lignocellulose hydrolysates using metabolic and evolutionary engineering

Demeke

Dietz

et al. 2013

Biotechnol Biofuels

272

213

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“…In this way, both laboratory and industrial strains of S. cerevisiae have been improved for phenotypes such as ethanol tolerance, thermotolerance, acetic acid tolerance, and fermentation performance (Table2). Some recent studies also combine metabolic engineering with genome shuffling (Wang & Hou, 2010; Jingping et al ., 2012; Tao et al ., 2012; Wang et al ., 2012a; Demeke et al ., 2013). These approaches are promising to optimize strains for second-generation bioethanol production.…”

Section: Natural and Artificial Diversitymentioning

confidence: 99%

“…Next, only fast-growing colonies are tested individually in small-scale fermentations, and only superior hybrids are used for a next round of shuffling (Shi et al ., 2009; Zheng et al ., 2011a, b, 2013a, b; Tao et al ., 2012). Other investigators have instead tried to first improve stress tolerance and found that hybrids generated after multiple rounds of genome shuffling and selection also showed increased general fermentation performance (Wei et al ., 2008; Cao et al ., 2009, 2010, 2012; Hou, 2009; Wang & Hou, 2010; Jingping et al ., 2012; Lu et al ., 2012; Wang et al ., 2012a). Alternatively, some researchers inoculated their entire hybrid population in a very high-gravity fermentation and harvested cells for a next round of shuffling when the viability of the culture had considerably dropped, thereby enriching for the best adapted hybrids (Hou, 2010; Liu et al ., 2011).…”

Section: Natural and Artificial Diversitymentioning

confidence: 99%

Improving industrial yeast strains: exploiting natural and artificial diversity

Steensels¹,

Snoek²,

Meersman³

et al. 2014

FEMS Microbiol Rev

380

288

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Yeasts have been used for thousands of years to make fermented foods and beverages, such as beer, wine, sake, and bread. However, the choice for a particular yeast strain or species for a specific industrial application is often based on historical, rather than scientific grounds. Moreover, new biotechnological yeast applications, such as the production of second-generation biofuels, confront yeast with environments and challenges that differ from those encountered in traditional food fermentations. Together, this implies that there are interesting opportunities to isolate or generate yeast variants that perform better than the currently used strains. Here, we discuss the different strategies of strain selection and improvement available for both conventional and nonconventional yeasts. Exploiting the existing natural diversity and using techniques such as mutagenesis, protoplast fusion, breeding, genome shuffling and directed evolution to generate artificial diversity, or the use of genetic modification strategies to alter traits in a more targeted way, have led to the selection of superior industrial yeasts. Furthermore, recent technological advances allowed the development of high-throughput techniques, such as ‘global transcription machinery engineering’ (gTME), to induce genetic variation, providing a new source of yeast genetic diversity.

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“…Saccharomyces cerevisiae was engineered for assembly of minicellulosomes by heterologous expression of a recombinant scaffolding protein from Clostridium cellulovorans and a chimeric endoglucanase E from Clostridium thermocellum which is helpful for higher yield of ethanol production (Hyeon et al 2010). Microaeration enhances productivity of bioethanol from LCW using ethanologenic E. coli (Okuda et al 2007); simultaneous saccharification and fermentation (SSF) using recombinant Saccharomyces cerevisiae results in high ethanol production of theoretical value (Jingping et al 2012). The saccharification of the lignocellulosic biomass by the enzymes and the subsequent fermentation of the sugars to ethanol by the yeast Saccharomyces and Zymomonas mixed with Kluyveromyces fragilis has produced improved ethanol production (Szambelan et al 2004).…”

Section: Fermentationmentioning

confidence: 99%