河北产区优选酿酒酵母的中试研究

将分离自河北产区的3株本土优良葡萄酒酿酒酵母菌株NJ5、N19、NJ17用于葡萄酒中试发酵,考查不同酵母菌株的发酵性能、所发酵葡萄酒的理化特征、多酚类物质含量和挥发性香气成分组成.结果表明,3株本土酿酒酵母具有良好的发酵性能,可生产具有典型地域特征的葡萄酒,有望于用于河北地区特色葡萄酒的生产.     

葡萄酒酿酒酵母菌基因工程改良

酿酒酵母是葡萄酒发酵工业中的主导微生物,其发酵性能直接影响葡萄酒的质量与生产成本,该文论述了基因工程在葡萄酒酿酒酵母菌种改良中的应用。     

不同酿酒酵母发酵对干红葡萄酒品质的影响

为得到优良的本土酿酒酵母（Saccharomyces cerevisiae）,以商业酿酒酵母（DS、CECA、CEC01）为对照,采用本土优良酿酒酵母WJ1、Q12发酵赤霞珠干红葡萄酒,测定其发酵过程中总酸、残糖、酒精度、花色苷、单宁和总酚含量的变化,并对葡萄酒进行感官评价。结果表明,不同酿酒酵母发酵赤霞珠干红葡萄酒过程中总酸、残糖、酒精度、花色苷、单宁和总酚含量变化趋势一致。本土酿酒酵母WJ1发酵的赤霞珠干红葡萄酒酸度较高,为6.92 g/L,残糖、酒精度、花色苷、单宁和总酚含量分别为3.32 g/L、15.0%vol、282.35 mg/L、204.95 mg/L、3 110.04 mg/L,感官评分为89分,显著高于商业酿酒酵母（P＜0.05）。酿酒酵母Q12发酵的赤霞珠干红葡萄酒酸度、残糖、酒精度分别为3.87 g/L、3.5 g/L、14.8%vol,花色苷、单宁和总酚含量分别为192.22 mg/L、205.01 mg/L、2 215.37 mg/L,感官评分为70分,显著低于商业酿酒酵母（P＜0.05）。因此,本土酿酒酵母WJ1可用作发酵赤霞珠干红葡萄酒的商业酵母。     

酿酒酵母ZGJ-1在猕猴桃果酒发酵中的研究及应用

为了将专利菌ZGJ-1在工业上进行广泛的应用并为猕猴桃产业开辟一条深加工新途径,分别以游离和固定化的酵母菌ZGJ-1为研究对象,采用单因素试验和正交试验,研究了猕猴桃果酒的最优发酵工艺条件。结果表明,固定化酿酒酵母ZGJ-1发酵果酒的最佳工艺参数为接种量5%,SO2添加量100 mg/L,起始糖度200 g/L。在此优化条件下,猕猴桃果酒酒精度为9.6%vol,残糖为32.28 g/L,发酵速度快,所产果酒香味浓郁,各项品质指标均达到相关国标标准。抗氧化能力试验结果表明,固定化酿酒酵母ZGJ-1发酵果酒对 ·OH、DPPH·、O2-·清除率分别为42%、96%、80%,显示其较好的抗氧化能力。     

不同酿酒酵母对起泡葡萄酒品质的影响

将经过一系列筛选得到的S1、S2、S3三株酿酒酵母以EC1118为对照进行起泡葡萄酒酿造试验,用自制装置对起泡葡萄酒瓶内发酵压力变化进行监控,并对起泡葡萄酒的理化指标、品评结果进行分析.结果表明,在相同加糖量情况下,不同酿酒酵母将糖转化为瓶内气体的效率不同;发酵生成的起泡葡萄酒与基酒相比,其挥发酸,酒精度均有所增加;还原糖、总酸在不同菌株间差异不明显;起泡酒外观、香气、口感的品评结果,依菌株不同存在差异.     

Determination of the Relative Ploidy in Different Saccharomyces cerevisiae Strains used for Fermentation and ‘Flor’ Film Ageing of Dry Sherry-type Wines

The full chromosomal karyotype of six enological Saccharomyces cerevisiae strains used for fermentation and biological ageing of sherry-type wines was studied. A genetic method based on the analysis of segregation frequencies of auxotrophic markers, among random spore progeny of hybrids, constructed between laboratory and industrial wine strains (Bakalinsky and Snow, 1990) was used. This method was combined with the analysis of strains by pulsed-field gel electrophoresis. The results obtained clearly indicate the presence of two, three or four copies of a chromosome in the industrial strains examined, and thus confirm that aneuploidy/polyploidy is not uncommon in these strains. In all strains examined, chromosome XIII polysomy is observed. This chromosome contains the ADH2 and ADH3 loci, that code for the ADHII and ADHIII isoenzymes of alcohol dehydrogenase, which are involved in ethanol oxidative utilization during biological ageing of wines. Tetrad analysis for the ‘flor formation’ character suggests two possibilities: this character is either regulated by at least a digenic system, or by only one gene present on a chromosome which is, at least, disomic.© 1997 John Wiley & Sons, Ltd.     

固定化酿酒酵母发酵香蕉酒的研制

介绍了以香蕉为原料采用固定化酿酒酵母发酵香蕉酒的工艺，并对分批和连续发酵工艺的关键点进行了研究。     

Exclusion of Saccharomyces kudriavzevii from a wine model system mediated by Saccharomyces cerevisiae

This study investigated the competition and potential hybrid generation between the species Saccharomyces cerevisiae and S. kudriavzevii in a wine-model environment. Our main goal was to understand why S. kudriavzevii has not been found in wine fermentations whilst their hybrids are present. Auxotrophic mutants (Ura(-) and Lys(-)) were used to favour the selection of hybrids and to specifically differentiate the two species in mixed fermentations carried out at different temperatures (17 °C, 24 °C and 31 °C). Both yeasts showed a reduction in their maximum specific growth rates in mixed fermentations, indicating a clear antagonistic effect between the two microorganisms. Temperature played an important role in this competition. In this way, S. kudriavzevii was less affected at 17 °C, but S. cerevisiae was clearly the best competitor at 31 °C, preventing the growth of S. kudriavzevii. Population levels of S. kudriavzevii always significantly decreased in the presence of S. cerevisiae. Ethanol was measured throughout the fermentations and in all cases S. kudriavzevii growth was arrested when ethanol levels were < 5 g/l, indicating that this compound did not influence the competitive exclusion of S. kudriavzevii. Killer factors were also discarded due to the K(-) R(-) phenotype of both strains. Finally, no prototrophic interspecific hybrids were isolated in small-scale fermentations at any temperature assayed. Our results show that the lack of competitiveness exhibited by S. kudriavzevii, especially at high temperatures, explains the absence of this species in wine fermentations, suggesting that natural S. cerevisiae × S. kudriavzevii hybrids most likely originated in wild environments rather than in industrial fermentations.     

The effects of grape must fermentation conditions on volatile alcohols and esters formed by Saccharomyces cerevisiae

Changes in aroma compounds synthesised from grape must during fermentation carried out by Saccharomyces cerevisiae, in semi-aerobic, anaerobic, short aeration conditions and after adding ergosterol and oleic acid to the must were studied. The biosynthesis of these aroma compounds was strongly dependent on the fermentation conditions and on the growth of the yeast. Ethanol, isoamyl alcohols, isobutyl alcohol, phenethyl alcohol and isoamyl, butyl and hexyl acetates were produced in greater concentrations in semiaerobic conditions, mainly during cellular growth. 1-Butanol and 1-pentanol were produced in greater levels in anaerobic conditions, when cellular growth was lower. Ergosterol and oleic acid added to the musts generally increased the levels of the aroma compounds in wine compared to those obtained in anaerobic conditions. © 1997 SCI.     

Genetic and enological analysis of selected Saccharomyces cerevisiae strains for wine production

The non‐wine Saccharomyces cerevisiae strain of 96581 was found to be a promising candidate for the production of white wine. It produced wines with fusel alcohols that were 57% higher than those produced by the wine yeasts studied and was also more efficient in the production of 2‐phenethyl acetate and 3‐methyl‐1‐butanol acetate. This study also shows that there is a difference in the ester‐formation efficiency for acetates relative to C6, C8 and C10 fatty acid esters for all the studied yeast strains. Therefore, it supports the view that other unidentified enzymes besides those regulated by ATF1 and ATF2 genes are involved in the production of ethyl esters of C6–C10 fatty acids. DNA analysis of the 25S, 18S, 5.8S and 5S ribosomal DNA genes in these strains showed high conservation. Despite the closely related nature of these yeast strains, the chemical profiles of the wines produced were significantly different.     

Genetic characterization of commercial Saccharomyces cerevisiae isolates recovered from vineyard environments

One hundred isolates of the commercial Saccharomyces cerevisiae strain Zymaflore VL1 were recovered from spontaneous fermentations carried out with grapes collected from vineyards located close to wineries in the Vinho Verde wine region of Portugal. Isolates were differentiated based on their mitochondrial DNA restriction patterns and the evaluation of genetic polymorphisms was carried out by microsatellite analysis, interdelta sequence typing and pulsed-field gel electrophoresis (PFGE). Genetic patterns were compared to those obtained for 30 isolates of the original commercialized Zymaflore VL1 strain. Among the 100 recovered isolates we found a high percentage of chromosomal size variations, most evident for the smaller chromosomes III and VI. Complete loss of heterozygosity was observed for two isolates that had also lost chromosomal heteromorphism; their growth and fermentative capacity in a synthetic must medium was also affected. A considerably higher number of variant patterns for interdelta sequence amplifications was obtained for grape-derived strains compared to the original VL1 isolates. Our data show that the long-term presence of strain VL1 in natural grapevine environments induced genetic changes that can be detected using different fingerprinting methods. The observed genetic changes may reflect adaptive mechanisms to changed environmental conditions that yeast cells encounter during their existence in nature.     

冰梨酒酿酒酵母的筛选

以鸭梨为原料,榨汁后经冷冻浓缩制成浓缩梨汁（即冰梨汁）,接入酿酒酵母（Saccharomyces cerevisiae）,在15 ℃下进行低温酒精发酵酿制成冰梨酒。通过比较8株酿酒酵母的发酵性能,及其所酿冰梨酒的理化指标、有机酸含量和感官品质,最终确定酿酒酵母R2为酿制冰梨酒的适宜菌种。该酵母生长繁殖快、降糖和产酒精能力强、发酵性能优良;酿出的冰梨酒酒香和谐,果香纯正,口感甜美醇厚、柔和爽口,具有冰梨酒特有的风味。     

Genetic control of chromosome stability in the yeast Saccharomyces cerevisiae

We have identified four new genetic loci: CHL2 (on chromosome XII), CHL3 (on chromosome XII); CHL4 (on chromosome IV), and CHL5 (on chromosome IX), controlling mitotic transmission of yeast chromosomes. The frequency of loss of chromosomes is 10-100-fold higher in chl5, chl2, chl3 and chl4 mutants than observed in wild-type strains. The mutants also show unstable maintenance of artificial circular minichromosomes with various chromosomal replicators (ARS) and one of the centromeric loci (CEN3, CEN4, CEN5 or CEN6). The instability of minichromosomes in the chl5, chl2, and chl4 mutants is due to the loss of minichromosomes in mitosis (1:0 segregation). In the chl3 mutant the instability of artificial minichromosomes is due to nondisjunction (2:0 segregation). The CHL3 gene therefore appears to affect the segregation of chromosomes during cell division.     

本土酿酒酵母的筛选及其低醇葡萄酒特性研究

以天津宝坻产区的三种葡萄为原料,分别从自然发酵的葡萄汁中筛选出340株酵母菌,经生理生化,产酸、酯、尿酶、H2S,发酵能力测定及26SrRNA测序,确定4株为酿酒酵母,用于贵人香低醇白葡萄酒的酿造。以商用酵母为对照,定量分析了不同酵母所酿酒中的香气成分、氨基甲酸乙酯含量,并进行了理化指标和感官测定,发现酵母C508和G611酿造的低醇酒具有更独特的香气特点,氨基甲酸乙酯的含量较低,微生物稳定性较高,更适合低醇酒的酿造。     

Genome renewal: A new phenomenon revealed from a genetic study of 43 strains of Saccharomyces cerevisiae derived from natural fermentation of grape musts

We have analyzed by genetic means 43 strains of Saccharomyces that had been isolated from fermenting grape musts in Italy. Twenty eight of these strains were isolated from 28 cellars in the Region of Emilia Romagna. The other 15 strains came from 5 fermentations at four cellars near the city of Arpino, which is located south and east of Rome. We found that 20 of the 28 strains from Emilia Romagna were heterozygous at from one to seven loci. The balance were, within the limits of our detection, completely homozygous. All these strains appeared to be diploid and most were homozygous for the homothallism gene (HO/HO). Spore viability varied greatly between the different strains and showed an inverse relation with the degree of heterozygosity. Several of the strains, and in particular those from Arpino, yielded asci that came from genetically different cells. These different cells could be interpreted to have arisen from a heterozygote that had sporulated and, because of the HO gene, yielded homozygous diploid spore clones. We propose that natural wine yeast strains can undergo such changes and thereby change a multiple heterozygote into completely homozygous diploids, some of which may replace the original heterozygous diploid. We call this process ‘genome renewal’.     

Diacetyl reduction by commercial Saccharomyces cerevisiae strains during vinification

Microbially derived diacetyl accumulation during vinification imparts a buttery wine aroma, which has stylistic implications. However, at higher concentrations diacetyl induces an aromatic off‐flavour. Saccharomyces cerevisiae is able to reduce diacetyl to below the sensory threshold. Therefore, characterization of the diacetyl reduction in commercial wine yeasts creates new opportunities to manage the risk of wine associated off‐flavours. Diacetyl reduction by two commercial S. cerevisiae strains was characterized in Pinot blanc grape must of the vintage 2012 with different initial diacetyl concentrations (0–50 mg/L). Highest diacetyl reduction was found in the first two days after wine yeasts were inoculated. No further decrease in diacetyl content was observed after the fourth day. All assays in which diacetyl was added showed the same final diacetyl concentration of approximately 2 mg/L. However, a significantly lower amount of diacetyl was found in grape must without adding diacetyl. The present results indicate that commercial wine yeasts are able to reduce much higher amounts of diacetyl than normally expected during the vinification procedure. However, the constant final diacetyl concentration indicates that diacetyl accumulation may be the result of wine matrix binding effects, which prevent a complete reduction by active wine yeasts. Copyright © 2013 The Institute of Brewing & Distilling.     

A systematic CEN library of the Saccharomyces cerevisiae genome

Progress in modern genetics is greatly facilitated by systematic resources that enable rapid and comprehensive analysis. Here we report the creation of a nearly complete systematic low‐copy (CEN URA3) library of the Saccharomyces cerevisiae genome that complements existing systematic high‐copy libraries. Copyright © 2010 John Wiley & Sons, Ltd.     

Effect of additives on the rehydration of Saccharomyces cerevisiae wine strains in active dry form: influence on viability and performance in the early fermentation phase

The effect of five additives on the rehydration process of three commercial Saccharomyces cerevisiae wine strains, in the form of active dry yeast, was tested using the approach of design of experiments. The response to additives was monitored by observing the viability, measured using fluorescence methodology at the end of the rehydration experiments, and fermentative performance, focusing attention on the first phase of fermentation, assessed based on ethanol production and the total number of cells after 48 h from the time of inoculation in synthetic must. The results showed a correlation between viability and the presence of magnesium in the rehydration medium. However, improvement in viability was not associated with better fermentation performance, which was not affected or in some cases significantly reduced. Among the additives examined, only rehydration with inactive dry yeast and ammonium showed a positive effect on the subsequent fermentations, but not for all of the strains tested. In general, considering all of the additives tested, no relationship was found between viability at the end of rehydration and fermentation performance. These findings suggest that the viability of the rehydrated yeast cells may not be a good index of fitness in the subsequent fermentation. Copyright © 2014 The Institute of Brewing & Distilling     

不同酿酒酵母菌发酵树莓果酒的理化特性

该研究以秋福树莓为原料,采用五种商业酿酒酵母菌（71B、CECA、VP5、BV818、Montrachet）酿制树莓果酒。实验测定分析了各树莓果酒样品的发酵曲线、理化指标、有机酸及非花色苷单体酚类物质含量,并进行了感官评价。结果表明,菌株VP5启动最为缓慢,菌株71B无明显降酸效果,菌株CECA和BV818感官评分略低,而酿酒酵母Montrachet发酵启动快速,发酵速率平缓,发酵彻底,酒样酒精度高,为9.77%vol;甘油生成能力强,为8.22 g/L;具有较强的降低柠檬酸和苹果酸的能力,且酿酒酵母Montrachet酒样感官评分最高,为43分。单体酚检测结果表明,其总酚含量最高,为21.39 mg/L,其中鞣花酸、没食子酸含量高,黄烷醇类含量居中,这有助于形成树莓果酒鲜艳的色泽,且避免强烈的苦涩感。故酿酒酵母Montrachet适合树莓果酒酿造的优良菌株。     

甘蔗汁酿酒酵母的筛选及特性

为了筛选适宜于甘蔗果酒的酿酒酵母,综合采用了富集培养、平板分离、产酒与产香实验、起酵实验及耐乙醇特性实验等方法,从自然发酵甘蔗渣中筛选获得1株优良的酿酒酵母G05.菌株G05具有起酵快、耐乙醇性较强、产酒率高、香气明显等特点,最适发酵温度28℃和发酵最适pH值为5.0,在含糖200g/L的甘蔗汁培养基中的乙醇产量、总酯产量分别为10.8％vol和1.2g/L.