共查询到17条相似文献,搜索用时 984 毫秒
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从大豆糖蜜中进行高产乙醇酵母的筛选和鉴定,并对其发酵特性进行研究。从大豆糖蜜中通过菌种的富集分离,TTC平板法初筛,耐乙醇能力及乙醇发酵能力的测定,筛选出一株乙醇产量达9.07%(V/V)的菌株P14。通过个体形态、菌落特征、生理生化及26S rDNA D1/D2区序列分析将菌株P14鉴定为酿酒酵母。研究了大豆糖蜜浓度及添加氮源和无机盐对酿酒酵母P14发酵生产乙醇的影响及酿酒酵母P14对大豆糖蜜中低聚糖的利用,结果表明大豆糖蜜浓度、添加氮源和无机盐对乙醇发酵影响显著,最佳的大豆糖蜜浓度为40%,添加氮源为1.2 g/L的蛋白胨;补加的无机盐为0.4 g/L MgSO4。在此培养基中发酵72 h后,糖蜜中90.10%的葡萄糖,91.23%的蔗糖,92.56%的棉籽糖和96.97%的水苏糖被酵母利用。因此大豆糖蜜中筛选出来的酿酒酵母P14具有较强的利用大豆糖蜜中的大豆低聚糖发酵产生乙醇的能力。 相似文献
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为获得适合刺梨果酒酿造的非酿酒酵母菌株,从刺梨自然发酵液中分离优质非酿酒酵母,通过形态学与26S rDNA序列分析来鉴定菌株;从葡萄糖耐受性、柠檬酸耐受性、酒精耐受性、二氧化硫耐受性、单宁耐受性、β-糖苷酶产生能力、硫化氢产生能力等方面分析菌株的生理特征;与酿酒酵母混合发酵刺梨果汁,从发酵刺梨果酒常规理化指标、感官品评以及香气物质方面探讨非酿酒酵母对刺梨果酒品质的影响。结果表明,利用赖氨酸筛选培养基从刺梨果实上筛选出80株非酿酒酵母,嗅闻法筛选出一株产香浓郁的菌株F13。形态学与分子生物学鉴定结果表明,F13为一株刺梨来源的葡萄汁有孢汉逊酵母;该菌株可耐受浓度为300 g/L葡萄糖、3%乙醇、3%柠檬酸、300 mg/L SO2以及25 g/L单宁处理。但酒精耐受性和β-糖苷酶产生能力不及酿酒酵母X16。此外,F13菌株不产硫化氢。F13与酿酒酵母混合发酵可降低刺梨果酒的酒精度和挥发酸,增加残糖量,分别为11.1%±0.39%、(0.67±0.03)g/L、(20.41±1.44)g/L。F13不影响刺梨果酒的感官品评,但可有效增加刺梨果酒中醇类物质的种类和含量,降低酯类物质种类和含量。本研究从刺梨自然发酵液中得到一株非酿酒酵母F13,对酿酒环境具有较优的耐受性(耐糖、酸、酒精度、二氧化硫),具有一定的工业化应用潜能。 相似文献
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研究酿酒酵母对乙醇耐受性的机理,对于发展乙醇生产有重要意义.酿酒酵母乙醇耐受性涉及到基因组水平上许多基因的复杂的相互作用,已知许多影响细胞膜的完整性和通透性、细胞壁结构、蛋白质构象,以及糖和氨基酸等的吸收等基因都与乙醇耐受性有关,与乙醇诱导相关的基因往往也与其他的环境因素如渗透压、热激、化学毒性、氧化压力等诱导的基因有关或重叠.因此,从基因转录动力学研究酿酒酵母乙醇耐受性并通过全转录工程构建乙醇耐受性工程菌己成为重要的研究热点.该文对近年来酿酒酵母乙醇耐受性分子机理以及全转录工程构建工程菌的研究作一综述,旨在为了解酵母乙醇耐受性机理和培育乙醇耐受性高产酵母菌株提供参考. 相似文献
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醇类物质是酿酒酵母在酒酿造过程中产生的主要代谢产物之一,酒精发酵过程中酿酒酵母代谢是产生醇类物质的主要来源,深入研究黄酒酿酒酵母醇类物质的代谢调控机制,对于高级醇的含量控制以及定向培育产乙醇及芳香醇的黄酒酿酒酵母工业菌株具有重要的指导意义。本文系统综述了黄酒中主要醇类物质的代谢途径及基因敲除方法、诱变育种技术以及发酵环境变化在酿酒酵母对醇类物质代谢调控中的应用,对黄酒酿酒酵母对醇类物质代谢调控系统的建立有重要的理论意义,为实现黄酒中醇类物质含量的精准调控提供了参考。 相似文献
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Tolerance mechanism of the ethanol-tolerant mutant of sake yeast 总被引:2,自引:0,他引:2
Ogawa Y Nitta A Uchiyama H Imamura T Shimoi H Ito K 《Journal of Bioscience and Bioengineering》2000,90(3):313-320
Several ethanol-tolerant mutants have been bred from industrial sake yeasts, but the mechanism of ethanol tolerance in these mutants has not been elucidated. After the determination of the entire genome sequence of Saccharomyces cerevisiae, various methods to monitor the whole-gene expression of the yeast have been developed. In this study, we used a commercially available nylon membrane on which virtually every gene of S. cerevisiae was spotted to compare expression profiles between the ethanol-tolerant mutant and its parent sake yeast to investigate the mechanism of ethanol tolerance in this mutant. As a result, we found that several genes were highly expressed only in the ethanol-tolerant mutant but not in the parent strain. These genes were known to be induced in cells that were exposed to various stresses, such as ethanol, heat, and high osmolarity, or at the stationary-phase but not at the log-phase. In the ethanol-tolerant mutant, the expression level of these stress-responsive genes was further increased after exposure to ethanol. We also found that substances such as catalase, glycerol and trehalose that may have protective roles under stressful conditions were accumulated in high amounts in the ethanol-tolerant mutant. The ethanol-tolerant mutant also exhibited resistance to other stresses including heat, high osmolarity and oxidative stress in addition to ethanol tolerance. These results indicate that the mutant exhibits multiple stress tolerance because of elevated expression of stress-responsive genes, resulting in accumulation of stress protective substances. 相似文献
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Belloch C Orlic S Barrio E Querol A 《International journal of food microbiology》2008,122(1-2):188-195
Along the fermentation process yeasts are affected by a succession of stress conditions that affect their viability and fermentation efficiency. Among the stress conditions the most relevant are high sugar concentration and low pH in musts, temperature and, as fermentation progresses, ethanol accumulation. Nowadays, due to the demanding nature of modern winemaking practices and sophisticated wine markets, there is an ever-growing search for particular wine yeast strains possessing a wide range of optimized, improved or novel enological characteristics. Traditionally, the species S. cerevisiae and S. bayanus within the Saccharomyces sensu stricto species are considered some of the most important yeast species involved in fermentation processes. However, in the last years, hybrid strains between the species S. cerevisiae, S. bayanus and S. kudriavzevii have been described as yeasts conducting the alcoholic fermentations and some of them are commercially available. Our results indicate that yeasts in the Saccharomyces sensu stricto complex were not affected by low pH or high glucose content in the media; however temperature and ethanol concentration variables appreciably affected their growth. The strains pertaining to S. cerevisiae were able to tolerate high temperature stress, whereas strains within S. bayanus and S. kudriavzevii were better adapted to growth at lower temperatures. Regarding to alcohol tolerance, S. cerevisiae is tolerating alcohol better than S. bayanus or S. kudriavzevii. Surprisingly, the natural hybrids between these species have adapted to growth under ethanol and temperature stress by inheriting competitive traits from one or another parental species. These results open new perspectives in the construction of new hybrid strains with biotechnological interest, as the characteristics of the parents may result in interesting combinations in the hybrids. 相似文献
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微生物在发酵过程中往往会面临一系列诸如高温、高渗透压、乙醇等压力。该研究探究了4种食品酵母对葡萄糖的流加强度和热激压力的生理响应差异性。结果表明,Pichia kudriavzevii和Saccharomyces cerevisiae的生长几乎没有受到升温压力的影响。高速流加的葡萄糖和梯度升温抑制了Cyberlindnera fabianii的还原糖消耗,而对其他酵母没有影响。P.kudriavzevii和S.cerevisiae的胞内海藻糖表现为对葡萄糖的流加和低压力热激(35、37℃)高度敏感,C.fabianii的胞内海藻糖均表现出低敏感性,而Candida tropicalis的胞内海藻糖仅在严重压力下(>39℃)才开始积累。在所有酵母中,P.kudriavzevii的海藻糖含量在发酵调控后变化最显著,增长了3.7倍。此外,除C.fabianii外,高速流加的葡萄糖有利于P.kudriavzevii、S.cerevisiae和C.tropicalis乙醇的积累,特别是P.kudriavzevii的乙醇含量最高,达到48 g/L。该研究结果可以用于高耐受性菌株的筛选,为生物乙醇和酿造食品的应用提供指导。 相似文献
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研究几种不同脂肪酸对酿酒酵母在存活率、生长速率和发酵方面的酒精耐性的影响。结果表明:培养基中添加两种不饱和脂肪酸(棕榈油酸和油酸)能显著增加酵母菌在酒精冲击下的存活率,其中棕榈油酸的效应更强。同时这些存活的酵母菌在含酒精培养基上的生长速率也比普通酵母菌更快,而两种饱和脂肪酸(棕榈酸和硬脂酸)在提高酵母菌存活率和生长速率方面几乎无贡献。同时在添加相同浓度不饱和脂肪酸的条件下,培养至稳定期的酵母菌比对数期酵母菌具有更高的存活率和更好的生长速率。但在发酵方面,添加短链脂肪酸(棕榈油酸和棕榈酸)能够使酵母菌发酵达到较高的酒精体积分数,这个结果与酵母菌生长耐酒精性的结果不一致,表明酵母菌生长和发酵的酒精耐性机制是不同的。 相似文献
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