酿酒酵母低温耐受机制的研究进展

酿酒酵母（Saccharomyces cerevisiae）和发酵温度是影响葡萄酒产量和品质的关键性因素。低温发酵可以促进酯类、醇类、酮类、萜烯类等芳香物质的合成,提高葡萄酒质量。然而,低温发酵会延长酿酒酵母的潜伏期,降低细胞活性和发酵速率,甚至使发酵过程中止。因此,研究酿酒酵母的低温耐受机制为解决葡萄酒低温发酵这一工业难题提供了理论依据。介绍了低温对不同酿酒酵母生理特性、发酵性能、基因表达和细胞成分变化的影响,以及识别和响应低温信号的分子机制等方面的研究进展。     

酿酒酵母酒精耐性研究进展

酿酒酵母是目前使用最广泛的菌种之一，它的耐酒精性能及其机理一直被广泛地关注及研究。本文介绍了目前国内外对酵母酒精耐性的研究方向和进展，主要内容包括耐酒精性能评价，以及酵母细胞膜、蛋白质、海藻糖和培养基组成等方面与酒精耐性的关系。     

多重耐性酿酒酵母的选育及其蔗汁酒精发酵的研究

本研究以酿酒酵母AS2.1189为亲株,利用亚硝酸诱变酵母并建立含561株诱变株的菌种库,通过耐性平板点种初筛法,经5次传代培养后筛选得到遗传性能稳定的耐性诱变株,其中Y75、Y226、Y324这3株是耐热、耐渗透压和耐酒精性能都有提高的诱变株。3株诱变株在亲株极限耐受条件下的生长速率和最终细胞浓度都要大于亲株。研究诱变株Y75在胁迫条件下利用蔗汁发酵酒精,结果表明Y75最高菌体浓度高出亲株约2.5个OD₆₀₀单位;Y75发酵液pH低于亲株约0.4个单位;Y75耗糖速率明显大于亲株,但最终残糖基本相同;发酵20 h后Y75的产酒度高于亲株约1%(体积分数,下同),Y75和亲株的最终产酒度为14.82%和14.22%。     

Cu^2＋对酿酒酵母酒精发酵影响的研究进展

铜制剂农药应用历史悠久,可有效的防治葡萄霜霉、白粉等病害,在全球葡萄园中使用频繁和广泛。不合理使用铜制剂农药会引起葡萄果实的铜污染,升高葡萄汁的铜含量,进而影响酿酒酵母正常的酒精发酵,最终影响葡萄酒的品质。综述了Cu^2＋对酿酒酵母生长活性和酒精发酵影响的研究进展,并针对已取得的研究成果进行展望,旨在为Cu^2＋对酿酒酵母影响的深入研究提供参考。     

酿酒酵母在纤维素酒精发酵中的应用

通过大量实验尝试了通常用于淀粉酒精发酵的酿酒酵母在纤维素酒精发酵过程中的应用情况,实验结果证明,酿酒酵母发酵纤维素原料水解液时,相对于淀粉酒精发酵来说,在抑制物等较多因素的影响下,加量比较大,发酵延迟期比较长。     

海藻糖含量与酿酒酵母酒精耐性的关系

对酿酒酵母(Saccharomyces cerevisiae BY-6)中性海藻糖酶缺失突变株(△nthl)的海藻糖含量和酒精耐性之间的关系进行了研究.结果表明,中性海藻糖酶缺失突变株细胞海藻糖含量较高,用18%vol的酒精处理4h后仍可保持高的细胞存活率,并且无呼吸缺陷型的出现,说明高海藻糖含量可以保护细胞膜,防止线粒体DNA丢失和胞内物质的外渗,与酵母的酒精耐性之间存在一定的关系.     

发酵促进剂在酒精发酵过程中对酿酒酵母的影响

概述目前酒精发酵工业生产中发酵促进剂组分对酿酒酵母的影响,通过对其有效作用机理的分析,为酒精发酵促进剂产品开发应用研究提供理论支持。     

酒精发酵过程中酿酒酵母海藻糖代谢的研究

研究了酿酒酵母在酒精发酵过程中酵母细胞内海藻糖的代谢。结果表明海藻糖的代谢受几种因素如底物浓度、发酵温度以及其他条件的调节与控制。在试验中对酿酒酵母细胞内海藻糖在整个酒精发酵过程中的生物功能作了简要的评价。     

紫外诱变选育高产酒精及酸的酿酒酵母

利用紫外辐照的方式对从葡萄表面筛选的菌株Y6进行诱变,选育出产酒精能力强、产酸能力高并且发酵性能稳定的酿酒酵母菌株。通过单因素试验选择酵母菌株距30 W紫外灯30 cm照射100 s,致死率为75.62%为最佳诱变条件。采用三苯基氯化四氮唑（TTC）法和溴甲酚绿法以及杜氏小管筛选出产酒精和产酸强的目标菌株Y6-5,并对其遗传稳定性进行研究。结果表明,诱变菌株Y6-5与出发菌株Y6相比较,其产酒精、产酸能力分别提高了28.13%和201.41%,并且遗传稳定性良好。     

提高酿酒酵母耐受性能的研究进展

近年来,随着酿酒酵母被广泛地应用于工业生产,其发酵产物乙醇受到各界的广泛关注。但由于酿酒酵母对乙醇的毒性作用很敏感及发酵过程中的动态变化,导致酿酒酵母的生长和代谢受到多种环境胁迫因素的抑制。如何提高酿酒酵母的耐受性成为当前研究的重中之重。通过综合分析酿酒酵母在发酵生产过程中的耐受机理及抑制因素,总结提高酵母耐受性能的方法,为提高酿酒酵母的耐受性提供见解。     

Inhibition of mitochondrial fragmentation during sake brewing causes high malate production in sake yeast

We previously demonstrated the presence and fragmentation of mitochondria during alcohol fermentation. Here, we show that Fis1p induces mitochondrial fragmentation, and inhibition of mitochondrial fragmentation causes higher malate production during sake brewing. These findings indicate that mitochondrial morphology affects the metabolism of constituents, providing a breeding strategy for high-malate-producing yeasts.     

酵母菌高糖耐受机制的研究进展

在酒精浓醪发酵生产中,酵母菌在高糖度、高渗透压等恶劣环境下发酵产生乙醇的性能与其耐受机制有密切的联系。该文以酵母菌高糖耐受机制为切入点,介绍了耐高糖酵母菌的来源,高糖胁迫下酵母菌的应激反应,归纳已公开报道的与酵母菌高糖耐受机制可能有关的基因,借鉴真菌及细菌在转录组学与蛋白质组学水平上耐受性能及机制的研究,为基因水平上酵母菌高糖耐受机制的相关研究提供参考。     

Phenotypes and brewing characteristics of sake yeast Kyokai no. 7 mutants resistant to valproate

Screening of drug‐resistant mutants of sake yeast strains has been a major method for creation of superior strains. We attempted to create a valproic acid (VPA)‐resistant mutant strain from sake yeast Kyokai No. 7 (K7). VPA is a branched‐chain fatty acid and is an inositol synthesis inhibitor in mammals and yeast. We succeeded in isolating a mutant of strain K7 that can survive long‐term in a VPA‐containing medium. This strain, K7‐VPA^LS, is significantly more resistant to not only VPA‐induced cell death but also ethanol in comparison with the parent strain. Further experiments showed that the new strain is likely to have a deficiency in inositol and/or phosphatidylinositol synthesis. The major characteristics of sake brewed by strain K7‐VPA^LS (compared with K7) were lower amino acidity, higher isoamyl acetate content without an increase in the isoamyl alcohol level and changes in constituent organic acids, particularly higher malate and succinate but lower acetate concentrations. In addition, taste sensor analysis revealed that K7‐VPA^LS‐brewed sake has milder sourness and higher saltiness or richness than K7‐brewed sake does. High isoamyl acetate production may be related to a deficiency in phosphatidylinositol because this compound directly inhibits alcohol acetyltransferase, an enzyme responsible for isoamyl acetate synthesis. Strain K7‐VPA^LS grew more rapidly than the parental strain did in a medium containing acetate as a sole carbon source, indicating that K7‐VPA^LS effectively assimilates acetate and converts it to malate and succinate through the glyoxylate cycle. Thus, strain K7‐VPA^LS shows improved characteristics for brewing of high‐quality sake. Copyright © 2017 The Institute of Brewing & Distilling     

Brewing characteristics of haploid strains isolated from sake yeast Kyokai No. 7

Sake yeast exhibit various characteristics that make them more suitable for sake brewing compared to other yeast strains. Since sake yeast strains are Saccharomyces cerevisiae heterothallic diploid strains, it is likely that they have heterozygous alleles on homologous chromosomes (heterozygosity) due to spontaneous mutations. If this is the case, segregation of phenotypic traits in haploid strains after sporulation and concomitant meiosis of sake yeast strains would be expected to occur. To examine this hypothesis, we isolated 100 haploid strains from Kyokai No. 7 (K7), a typical sake yeast strain in Japan, and compared their brewing characteristics in small‐scale sake‐brewing tests. Analyses of the resultant sake samples showed a smooth and continuous distribution of analytical values for brewing characteristics, suggesting that K7 has multiple heterozygosities that affect brewing characteristics and that these heterozygous alleles do segregate after sporulation. Correlation and principal component analyses suggested that the analytical parameters could be classified into two groups, indicating fermentation ability and sake flavour. Copyright © 2008 John Wiley & Sons, Ltd.     

环境对酒精酵母产生乙醇耐性的影响

乙醇对细胞的抑制主要表现在对生长率、发酵率、糖分解酶、膜势能的抑制及膜磷脂的裂解,主要阐述了渗透压和温度对酒精酵母产生乙醇耐性的影响。     

影响酒精酵母产生乙醇耐性的因素

乙醇对细胞的抑制主要表现在对生长率、发酵率、糖分解酶、膜势能的抑制及膜磷脂的裂解。该文主要阐述了细胞质膜不饱和脂肪酸、曲霉蛋白脂、特定的崮醇及加氧作用对酒精酵母产生乙醇耐性的影响。     

酵母菌高糖胁迫机制的研究进展

耐高糖酵母在高糖的发酵环境下仍能有效发酵,这与酵母的高糖胁迫机制密切相关。深刻了解耐高糖酵母的胁迫机制,对定向改造酵母菌的性能和酿酒工业具有重要意义。该文综述了耐高糖酵母的筛选和与酵母菌高糖胁迫机制相关的代谢组学、转录组学、蛋白质组学和基因组学的研究进展,为酵母菌高糖胁迫机理的进一步研究提供参考。     

酿酒活性干酵母(AADY)的研究

酿酒活性干酵母（AADY）是现代高新技术融合发展的一种生物活性制品，具有发酵性能优良、细胞耐性强、絮凝性好、保存期长等，带动了酿酒工业的产业结构调整和升级。该文综述了现代生物工程育种技术、增强酵母菌抗逆性的发酵动力学、干燥技术的研究进展及干燥过程中保护剂的添加给AADY的持续发展提供了广阔的前景。     

Mitochondrial activity of sake brewery yeast affects malic and succinic acid production during alcoholic fermentation

The mitochondrial states and activities of production yeasts used in the fermentation industry vary according to the availability of oxygen, size of the fermentation tank and temperature of the raw material. However, the involvement of the mitochondrial states of these yeasts in the production profile of organic acids during alcoholic fermentation has not been investigated in detail. In this study, the effects of the mitochondrial state of a sake brewing yeast on the organic acid production profile during an alcoholic fermentation process were investigated. It was elucidated that the mitochondrial state during the propagation stage significantly affected the mitochondrial morphology and the organic acid production profile during the alcoholic fermentation. When yeast mitochondria were active, they were highly branched in the propagation stage, and the yeast cells produced significantly more succinate and less malate. In contrast, when the yeast mitochondria were inactive, they were long and filamentous in appearance, and the yeast produced significantly less succinate and more malate. The change in malic acid content was reversed when an uncoupler of mitochondrial membrane potential, carbonylcyanide p‐trifluoromethoxyphenylhydrazone, was added to the culture, indicating that the change in the organic acid production profile could be attributed to mitochondrial activity. Furthermore, the content of malic acid and succinic acid could be converted from a respirative to a fermentative profile by exposing the yeast to a mitochondrion‐inactivating environment for 12 or 24 h. Taken together, it was shown that the mitochondrial status of the yeast affects malic acid production during alcoholic fermentation. Copyright © 2012 The Institute of Brewing & Distilling