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1.
Virginie Ansanay-Galeote Bruno Blondin Sylvie Dequin Jean-Marie Sablayrolles 《Biotechnology letters》2001,23(9):677-681
When 4% (v/v) ethanol was added progressively to two strains exhibiting different fermentative abilities, K1 (a commercial wine strain) and V5 (a strain derived of a wine yeast), the fermentation rate correlated directly to the ethanol concentration for both strains. In contrast, the effect of sudden addition of 2%, 4% or 6% (v/v) ethanol was different depending on the strain. While the same effect was observed for K1 whatever the way of ethanol addition, V5 required an adaptation period after the shock addition of ethanol. 相似文献
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van de Laar T Visser C Holster M López CG Kreuning D Sierkstra L Lindner N Verrips T 《Biotechnology and bioengineering》2007,96(3):483-494
Saccharomyces cerevisiae is a widely used host organism for the production of heterologous proteins, often cultivated in glucose-based fed-batch processes. This production system however has many factors limiting the productivity, mainly towards the end of the fermentation. For the optimised production of a Camelid antibody fragment this process was evaluated. In shake flask cultivations, it was found that ethanol has a strong effect on productivity increase and therefore glucose and ethanol fed-batch fermentations were compared. It appeared that specific heterologous protein production was up to five times higher in the ethanol cultivation and could be further optimised. Then the key characteristics of ethanol fed-batch fermentations such as growth rate and specific production were determined under ethanol limitation and accumulation and growth limiting conditions in the final phase of the process. It appeared that an optimal production process should have an ethanol accumulation throughout the feed phase of approximately 1% v/v in the broth and that production remains very efficient even in the last phase of the process. This productivity increase on ethanol versus glucose was also proven for several other Camelid antibody fragments some of which were heavily impaired in secretion on glucose, but very well produced on ethanol. This leads to the suggestion that the ethanol effect on improved heterologous protein production is linked to a stress response and folding and secretion efficiency. 相似文献
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Comparisons of five Saccharomyces cerevisiae strains for ethanol production from SPORL‐pretreated lodgepole pine
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Haifeng Zhou Tianqing Lan Bruce S. Dien Ronald E. Hector J. Y. Zhu 《Biotechnology progress》2014,30(5):1076-1083
The performances of five yeast strains under three levels of toxicity were evaluated using hydrolysates from lodgepole pine pretreated by Sulfite Pretreatment to Overcome the Recalcitrance of Lignocelluloses (SPORL). The highest level of toxicity was represented by the whole pretreated biomass slurry, while intermediate toxicity was represented by the hydrolysate with partial loading of pretreatment spent liquor. The zero toxicity was represented using the enzymatic hydrolysate produced from thoroughly washed SPORL lodgepole pine solids. The results indicate that strains D5A and YRH400 can tolerate the whole pretreated biomass slurry to produce 90.1 and 73.5% theoretical ethanol yield. Strains Y1528, YRH403, and FPL450 did not grow in whole hydrolysate cultures and were observed to have lower ethanol productivities than D5A and YRH400 on the hydrolysate with intermediate toxicity. Both YRH400 and YRH403 were genetically engineered for xylose fermentation but were not able to consume xylose efficiently in hydrolysate. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:1076–1083, 2014 相似文献
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Michael J. Harsch Soon A. Lee Matthew R. Goddard & Richard C. Gardner 《FEMS yeast research》2010,10(1):72-82
Laboratory strains of yeast ( Saccharomyces cerevisiae ) based on S288C ferment grape juice relatively poorly. We show that slow fermentation appears to be inherent to this strain, because the original S288C isolate shows fermentation similar to current laboratory isolates. We demonstrate further that some auxotrophic mutations in the laboratory strain show reduced rates of fermentation in grape juice, with lysine auxotrophs particularly impaired compared with isogenic Lys+ strains. Supplementing lysine at a 10-fold higher concentration than recommended allowed yeast cultures to reach higher final cell densities and restored the fermentation rate of auxotrophic strains to those of the corresponding wild-type strains. However, even with the additional supplementation, the fermentation rates of S288C strains were still slower than those of a commercial wine yeast strain. Conditions were developed that enable auxotrophic laboratory strains derived from S288C to ferment grape juice to completion with high efficiency on a laboratory scale. Fermentation in media based on grape juice will allow the suite of molecular genetic tools developed for these laboratory strains to be used in investigations of complex ferment characteristics and products. 相似文献
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VariousSaccharomyces cerevisiae strains were transformed with a 2 μ-based multicopy expression plasmid, pYIGP, carryingKluyveromyces marxianus inulinase gene under the control ofGAPDH promoter. Among them two strains, SEY2102 and 2805, showed high levels of cell growth and inulinase expression, and were
selected to study their fermentation properties on inulin. Jerusalem artichoke inulin was more effective for cell growth (10∼11
g-dry wt./L at 48 hr) and inulinase expression (1.0 units/mL with SEY2102/pYIGP and 2.5 units/mL with 2805/pYIGP) than other
inulin sources such as dahlia and chicory. It was also found that maximal ethanol production of 9 g/L was obtained from Jerusalem
artichoke inulin at the early stationary phase (around 30 hr), indicating that recombinantS. cerevisiae cells secreting exoinulinase could be used for the simultaneous saccharification of inulin and ethanol fermentation. 相似文献
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《Critical reviews in biotechnology》2013,33(1):22-48
Lignocellulosic biomass from agricultural and agro-industrial residues represents one of the most important renewable resources that can be utilized for the biological production of ethanol. The yeast Saccharomyces cerevisiae is widely used for the commercial production of bioethanol from sucrose or starch-derived glucose. While glucose and other hexose sugars like galactose and mannose can be fermented to ethanol by S. cerevisiae, the major pentose sugars D-xylose and L-arabinose remain unutilized. Nevertheless, D-xylulose, the keto isomer of xylose, can be fermented slowly by the yeast and thus, the incorporation of functional routes for the conversion of xylose and arabinose to xylulose or xylulose-5-phosphate in Saccharomyces cerevisiae can help to improve the ethanol productivity and make the fermentation process more cost-effective. Other crucial bottlenecks in pentose fermentation include low activity of the pentose phosphate pathway enzymes and competitive inhibition of xylose and arabinose transport into the cell cytoplasm by glucose and other hexose sugars. Along with a brief introduction of the pretreatment of lignocellulose and detoxification of the hydrolysate, this review provides an updated overview of (a) the key steps involved in the uptake and metabolism of the hexose sugars: glucose, galactose, and mannose, together with the pentose sugars: xylose and arabinose, (b) various factors that play a major role in the efficient fermentation of pentose sugars along with hexose sugars, and (c) the approaches used to overcome the metabolic constraints in the production of bioethanol from lignocellulose-derived sugars by developing recombinant S. cerevisiae strains. 相似文献
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Petra Bafrncová Daniela šmogrovičová Iveta Sláviková Jaroslava Pátková Zoltán Dömény 《Biotechnology letters》1999,21(4):337-341
The final ethanol concentration achieved was increased by 17% (to 103 g ethanol/l) when excess assimilable nitrogen was added to the batch very high gravity (VHG) ethanolic fermentations by Saccharomyces cerevisiae. The supplementation of the media with 12 g yeast extract l–1, 0.3 g cell walls l–1, 3 g glycine l–1 and 20 g soya flour l–1 led to halving reduction of the fermentation time to 28 h. The ethanol productivity was enhanced by more than 50% (to achieved value 3.3 g l–1 h–1). 相似文献
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K. Piršelová D. Šmogrovičová Š. Baláž 《World journal of microbiology & biotechnology》1993,9(3):338-341
Static fermentation of starch to ethanol by a co-culture of Saccharomycopsis fibuligera and Saccharomyces cerevisiae without addition of nutritional supplements was investigated with respect to initial starch concentration, pH of the media and initial dry weight ratio of Sps. fibuligera to Sacc. cerevisiae biomass (I
R).Optimal conditions for ethanol production were: starch from 20 to 30 g/l; initial pH values from 5.8 to 6.0; and I
R values of 2.0 or 3.0. The highest attained ethanol concentration, 13.7 g/l, represented 88% of the theoretical yield.K. Pirelová, D. mogroviová and . Balá are with the Department of Biochemical Technology, Faculty of Chemical Technology, Slovak Polytechnic University, Radlinského 9, 81237 Bratislava, Slovak Republic. 相似文献
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Berthels NJ Cordero Otero RR Bauer FF Thevelein JM Pretorius IS 《FEMS yeast research》2004,4(7):683-689
While unfermented grape must contains approximately equal amounts of the two hexoses glucose and fructose, wine producers worldwide often have to contend with high residual fructose levels (>2 gl(-1)) that may account for undesirable sweetness in finished dry wine. Here, we investigate the fermentation kinetics of glucose and fructose and the influence of certain environmental parameters on hexose utilisation by wine yeast. Seventeen Saccharomyces cerevisiae strains, including commercial wine yeast strains, were evaluated in laboratory-scale wine fermentations using natural Colombard grape must that contained similar amounts of glucose and fructose (approximately 110 gl(-1) each). All strains showed preference for glucose, but to varying degrees. The discrepancy between glucose and fructose utilisation increased during the course of fermentation in a strain-dependent manner. We ranked the S. cerevisiae strains according to their rate of increase in GF discrepancy and we showed that this rate of increase is not correlated with the fermentation capacity of the strains. We also investigated the effect of ethanol and nitrogen addition on hexose utilisation during wine fermentation in both natural and synthetic grape must. Addition of ethanol had a stronger inhibitory effect on fructose than on glucose utilisation. Supplementation of must with assimilable nitrogen stimulated fructose utilisation more than glucose utilisation. These results show that the discrepancy between glucose and fructose utilisation during fermentation is not a fixed parameter but is dependent on the inherent properties of the yeast strain and on the external conditions. 相似文献
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甘油是酿酒酵母乙醇代谢途径中的主要副产物,降低甘油生成,可以提高乙醇的产率和原料的利用率。以工业酒精酵母单倍体S1(MATa)为研究对象,构建了一个4.5 kb左右的基因敲除突变盒gpd2Δ::PGK1PT-POS5-HyBR,利用醋酸锂转化法转入S1,得到重组菌S3(gpd2Δ::PGK1PT-POS5-HyBR),使得工业酒精酵母在敲除GPD2的同时整合过表达了NADH激酶基因POS5。结果表明,在150 g/L的葡萄糖摇瓶发酵实验中,重组菌S3在不影响菌株生理特性的条件下,乙醇得率(g ethanol/g glucose)比原始菌株S1提高了8%,甘油得率(g glycerol/g glucose)降低了33.64%。本研究证明过表达NADH激酶基因可降低乙醇发酵中副产物甘油的生成并提高乙醇得率。 相似文献
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Almeida JR Runquist D Sànchez i Nogué V Lidén G Gorwa-Grauslund MF 《Biotechnology journal》2011,6(3):286-299
Conversion of agricultural residues, energy crops and forest residues into bioethanol requires hydrolysis of the biomass and fermentation of the released sugars. During the hydrolysis of the hemicellulose fraction, substantial amounts of pentose sugars, in particular xylose, are released. Fermentation of these pentose sugars to ethanol by engineered Saccharomyces cerevisiae under industrial process conditions is the subject of this review. First, fermentation challenges originating from the main steps of ethanol production from lignocellulosic feedstocks are discussed, followed by genetic modifications that have been implemented in S. cerevisiae to obtain xylose and arabinose fermenting capacity per se. Finally, the fermentation of a real lignocellulosic medium is discussed in terms of inhibitory effects of furaldehydes, phenolics and weak acids and the presence of contaminating microbiota. 相似文献
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Luis Caspeta Jesús Coronel Arturo Montes de Oca Eduardo Abarca Lidia González Alfredo Martínez 《Biotechnology and bioengineering》2019,116(10):2587-2597
Thermal damage, high osmolarity, and ethanol toxicity in the yeast Saccharomyces cerevisiae limit titer and productivity in fermentation to produce ethanol. We show that long-term adaptive laboratory evolution at 39.5°C generates thermotolerant yeast strains, which increased ethanol yield and productivity by 10% and 70%, in 2% glucose fermentations. From these strains, which also tolerate elevated-osmolarity, we selected a stable one, namely a strain lacking chromosomal duplications. This strain (TTY23) showed reduced mitochondrial metabolism and high proton efflux, and therefore lower ethanol tolerance. This maladaptation was bolstered by reestablishing proton homeostasis through increasing fermentation pH from 5 to 6 and/or adding potassium to the media. This change allowed the TTY23 strain to produce 1.3–1.6 times more ethanol than the parental strain in fermentations at 40°C with glucose concentrations ~300 g/L. Furthermore, ethanol titers and productivities up to 93.1 and 3.87 g·L −1·hr −1 were obtained from fermentations with 200 g/L glucose in potassium-containing media at 40°C. Albeit the complexity of cellular responses to heat, ethanol, and high osmolarity, in this study we overcome such limitations by an inverse metabolic engineering approach. 相似文献
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Improved ethanol tolerance of Saccharomyces cerevisiae strains by increases in fatty acid unsaturation via metabolic engineering 总被引:2,自引:0,他引:2
Susumu Kajiwara Keiko Suga Hidetaka Sone Katsumi Nakamura 《Biotechnology letters》2000,22(23):1839-1843
To enhance the ethanol tolerance of Saccharomyces cerevisiae, the Arabidopsis thaliana FAD2 gene and/or the S. cerevisiae OLE1 gene were over-expressed in this yeast. The transformant over-expressing both these genes could not only synthesize dienoic fatty acids but also increased the unsaturated fatty acid content of membrane lipid and then showed the highest viability in the presence of 15% (v/v) ethanol. 相似文献
18.
Zastrow CR Hollatz C de Araujo PS Stambuk BU 《Journal of industrial microbiology & biotechnology》2001,27(1):34-38
Maltotriose, the second most abundant sugar of brewer's wort, is not fermented but is respired by several industrial yeast
strains. We have isolated a strain capable of growing on a medium containing maltotriose and the respiratory inhibitor, antimycin
A. This strain produced equivalent amounts of ethanol from 20 g l−1 glucose, maltose, or maltotriose. We performed a detailed analysis of the rates of active transport and intracellular hydrolysis
of maltotriose by this strain, and by a strain that does not ferment this sugar. The kinetics of sugar hydrolysis by both
strains was similar, and our results also indicated that yeast cells do not synthesize a maltotriose-specific α-glucosidase.
However, when considering active sugar transport, a different pattern was observed. The maltotriose-fermenting strain showed
the same rate of active maltose or maltotriose transport, while the strain that could not ferment maltotriose showed a lower
rate of maltotriose transport when compared with the rates of active maltose transport. Thus, our results revealed that transport
across the plasma membrane, and not intracellular hydrolysis, is the rate-limiting step for the fermentation of maltotriose
by these Saccharomyces cerevisiae cells. Journal of Industrial Microbiology & Biotechnology (2001) 27, 34–38.
Received 13 January 2001/ Accepted in revised form 29 May 2001 相似文献
19.
Development of novel carrier using natural zeolite and continuous ethanol fermentation with immobilized Saccharomyces cerevisiae in a bioreactor 总被引:1,自引:0,他引:1
Sho Shindo Susumu Takata Haruo Taguchi Noboru Yoshimura 《Biotechnology letters》2001,23(24):2001-2004
A natural zeolite, easily vitrified and blown at 1300 °C with a high porosity and diam. of 5–100 m, was used to immobilize Saccharomyces cerevisiae at 3.6 × 108 cells ml–1 carrier. When the abilities of natural zeolite carrier were compared with glass beads, the capacity for immobilization and alcohol fermentation activity were, respectively, 2-fold higher and 1.2-fold higher than that of glass beads. Continuous alcohol fermentation was stable for over 21 d without breakage of the carrier. 相似文献
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Katsunori Yoshikawa Tadamasa Tanaka Chikara Furusawa Keisuke Nagahisa Takashi Hirasawa & Hiroshi Shimizu 《FEMS yeast research》2009,9(1):32-44
We quantified the growth behavior of all available single gene deletion strains of budding yeast under ethanol stress. Genome-wide analyses enabled the extraction of the genes and determination of the functional categories required for growth under this condition. Statistical analyses revealed that the growth of 446 deletion strains under stress induced by 8% ethanol was defective. We classified these deleted genes into known functional categories, and found that many were important for growth under ethanol stress including several categories that have not been characterized, such as peroxisome. We also performed genome-wide screening under osmotic stress and identified 329 osmotic-sensitive strains. We excluded these strains from the 446 ethanol-sensitive strains to extract the genes whose deletion caused sensitivity to ethanol-specific (359 genes), osmotic-specific (242 genes), and both stresses (87 genes). We also extracted the functional categories that are specifically important for growth under ethanol stress. The genes and functional categories identified in the analysis might provide clues to improving ethanol stress tolerance among yeast cells. 相似文献