Wine production is a complex process from the vineyard to the winery. On this journey, microbes play a decisive role. From the environment where the vines grow, encompassing soil, topography, weather and climate through to management practices in vineyards, the microbes present can potentially change the composition of wine. Introduction of grapes into the winery and the start of winemaking processes modify microbial communities further. Recent advances in next-generation sequencing (NGS) technology have progressed our understanding of microbial communities associated with grapes and fermentations. We now have a finer appreciation of microbial diversity across wine producing regions to begin to understand how diversity can contribute to wine quality and style characteristics. In this review, we highlight literature surrounding wine-related microorganisms and how these affect factors interact with and shape microbial communities and contribute to wine quality. By discussing the geography, climate and soil of environments and viticulture and winemaking practices, we claim microbial biogeography as a new perspective to impact wine quality and regionality. Depending on geospatial scales, habitats, and taxa, the microbial community respond to local conditions. We discuss the effect of a changing climate on local conditions and how this may alter microbial diversity and thus wine style. With increasing understanding of microbial diversity and their effects on wine fermentation, wine production can be optimised with enhancing the expression of regional characteristics by understanding and managing the microbes present.Copyright © 2019 Liu, Zhang, Chen and Howell.

The main role of acidity and pH is to confer microbial stability to wines. No less relevant, they also preserve the color and sensory properties of wines. Tartaric and malic acids are generally the most prominent acids in wines, while others such as succinic, citric, lactic, and pyruvic can exist in minor concentrations. Multiple reactions occur during winemaking and processing, resulting in changes in the concentration of these acids in wines. Two major groups of microorganisms are involved in such modifications: the wine yeasts, particularly strains of Saccharomyces cerevisiae, which carry out alcoholic fermentation; and lactic acid bacteria, which commonly conduct malolactic fermentation. This review examines various such modifications that occur in the pre-existing acids of grape berries and in others that result from this microbial activity as a means to elucidate the link between microbial diversity and wine composition.

Lactic acid bacteria (LAB) are Gram positive bacteria frequently used in the food industry for fermentation, mainly transformation of carbohydrates into lactic acid. In addition, these bacteria also have the capacity to metabolize citrate, an organic acid commonly found in food products. Its fermentation leads to the production of 4-carbon compounds such as diacetyl, resulting in a buttery flavor desired in dairy products. Citrate metabolism is known to have several beneficial effects on LAB physiology. Nevertheless, a controversial effect of citrate has been described on the acid tolerance of the wine bacterium Oenococcus oeni. This observation raises questions about the effect of citrate on the capacity of O. oeni to conduct malolactic fermentation in highly acidic wines. This review aims to summarize the current understanding of citrate metabolism in LAB, with a focus on the wine bacterium O. oeni. Metabolism with the related enzymes is detailed, as are the involved genes organized in cit loci. The known systems of cit locus expression regulation are also described. Finally, the beneficial effects of citrate catabolism on LAB physiology are reported and the negative impact observed in O. oeni is discussed.

The main objective of the present study was to evaluate terroir's role in white and red wine characteristics through human perceptions and electronic assessment. Douro wines, originating from the Douro Demarcated Region (DDR) in the North of Portugal, are renowned for their distinct terroir and historical significance. This study investigates twenty-one Douro wine samples (ten white, eleven red) from Baixo Corgo and Douro Superior through Fourier Transform Infrared (FTIR) spectroscopy, Electronic Nose (E-nose) analysis, and Quantitative Descriptive Analysis (QDA). The research has uncovered unique profiles for each sub-region, influenced by factors such as pH, alcohol content, and acidity. Through principal component analysis, the electronic nose analysis identifies separate clusters in red wines and highlights notable aromatic differences in white wines. The sensory analysis via quantitative descriptive analysis provides detailed wine profiles, emphasizing attributes such as persistence, sweetness, and acidity. Furthermore, emotional responses during wine tasting were assessed using FaceReader analysis, which revealed a range of emotions like happiness, sadness, surprise, fear, and disgust, with different intensities over time. These findings provide valuable insights for consumers, producers, and the enogastronomic industry.

Wine production in Cyprus has strong cultural ties with the island’s tradition, influencing local and foreign consumers’ preferences and contributing significantly to Cyprus’ economy. A key contributor to wine quality and sensorial characteristics development is the microbiota that colonizes grapes and performs alcoholic fermentation. Still, the microbial patterns of wines produced in different geographic regions (terroir) in Cyprus remain unknown. The present study investigated the microbial diversity of five terroirs in Cyprus, two from the PGI Lemesos region [Kyperounta (PDO Pitsilia) and Koilani (PDO Krasochoria)], and three from the PGI Pafos region [Kathikas (PDO Laona Akamas), Panayia, and Statos (PDO Panayia)], of two grape varieties, Xynisteri and Maratheftiko, using high-throughput amplicon sequencing. Through a longitudinal analysis, we examined the evolution of the bacterial and fungal diversity during spontaneous alcoholic fermentation. Both varieties were characterized by a progressive reduction in their fungal alpha diversity (Shannon index) throughout the process of fermentation. Additionally, the study revealed a distinct separation among different terroirs in total fungal community composition (beta-diversity) for the variety Xynisteri. Also, Kyperounta terroir had a distinct total fungal beta-diversity from the other terroirs for Maratheftiko. Similarly, a significant distinction was demonstrated in total bacterial diversity between the PGI Lemesos region and the PGI Pafos terroirs for grape juice of the variety Xynisteri. Pre-fermentation, the fungal diversity for Xynisteri and Maratheftiko was dominated by the genera Hanseniaspora, Aureobasidium, Erysiphe, Aspergillus, Stemphylium, Penicillium, Alternaria, Cladosporium, and Mycosphaerella. During and post-fermentation, the species Hanseniaspora nectarophila, Saccharomyces cerevisiae, Hanseniaspora guilliermondii, and Aureobasidium pullulans, became the predominant in most must samples. Regarding the bacterial diversity, Lactobacillus and Streptococcus were the predominant genera for both grape varieties in all stages of fermentation. During fermentation, an increase was observed in the relative abundance of some bacteria, such as Acetobacter, Gluconobacter, and Oenococcus oeni. Finally, the study revealed microbial biomarkers with statistically significant higher relative representation, associated with each geographic region and each grape variety, during the different stages of fermentation. The present study’s findings provide an additional linkage between the grape microbial community and the wine terroir.

Despite being used chiefly for fermenting the sugars of grape must to alcohol, wine yeasts (most prominently) play a pivotal role in the final aroma profiles of wines. Strain selection, intentionally incorporating non- yeast in so-called mixed-culture fermentations, and genetic modifications of have all been shown to greatly enhance the chemical composition and sensory profile of wines. In this Review, we highlight how wine researchers employ fermenting yeasts to expand on the aroma profiles of the wines they study.

The grape is one of the oldest and most important horticultural crops. Grape and wine aroma has long been of cultural and scientific interest. The diverse compound classes comprising aroma result from multiple biosynthetic pathways. Only fairly recently have researchers begun to elucidate the genetic mechanisms behind the biosynthesis and metabolism of grape volatile compounds. This review summarizes current findings regarding the genetic bases of grape and wine aroma with an aim towards highlighting areas in need of further study. From the literature, we compiled a list of functionally characterized genes involved in berry aroma biosynthesis and present them with their corresponding annotation in the grape reference genome.© The Author(s) 2019.

In the last two decades knowledge on lactic acid bacteria (LAB) associated with wine has increased considerably. Investigations on genetic and biochemistry of species involved in malolactic fermentation, such as Oenococcus oeni and of Lactobacillus have enabled a better understand of their role in aroma modification and microbial stability of wine. In particular, the use of molecular techniques has provided evidence on the high diversity at species and strain level, thus improving the knowledge on wine LAB taxonomy and ecology. These tools demonstrated to also be useful to detect strains with potential desirable or undesirable traits for winemaking purposes. At the same time, advances on the enzymatic properties of wine LAB responsible for the development of wine aroma molecules have been undertaken. Interestingly, it has highlighted the high intraspecific variability of enzymatic activities such as glucosidase, esterase, proteases and those related to citrate metabolism within the wine LAB species. This genetic and biochemistry diversity that characterizes wine LAB populations can generate a wide spectrum of wine sensory outcomes. This review examines some of these interesting aspects as a way to elucidate the link between LAB diversity with wine aroma and flavour. In particular, the correlation between inter- and intra-species diversity and bacterial metabolic traits that affect the organoleptic properties of wines is highlighted with emphasis on the importance of enzymatic potential of bacteria for the selection of starter cultures to control MLF and to enhance wine aroma.Copyright © 2016 Elsevier B.V. All rights reserved.

During this study, the physicochemical properties, color, and volatile aroma compounds of the original wines produced from the grape varieties ‘Hassan’, ‘Zuoshaner’, ‘Beibinghong’, ‘Zuoyouhong’, ‘Beta’, ‘Shuanghong’, ‘Zijingganlu’, ‘Cabernet Sauvignon’, and ‘Syrah’ were determined and sensory evaluation was performed. Results indicated that ‘Hassan’ contained the most solids, ‘Zuoshaner’ produced the most total acid, residual sugar, total anthocyanin, and total phenol, and ‘Shuanghong’ produced the most tannin. Calculation of the chroma and hue of the wines according to the CIEL*a*b* parameters revealed that the ‘Cabernet Sauvignon’ wines were the brightest of the nine varieties and that the ‘Zuoshaner’ wines had the greatest red hue and yellow hue and the greatest saturation’. A total of 52 volatile compounds were identified and quantified in nine wine samples by HS-GC-IMS analysis, with the most significant number of species detected being 20 esters, followed by 16 alcohols, 8 aldehydes, four ketones, one terpene, and one furan, with the highest total volatile compound content being ‘Beta’. A total of 14 volatile components with OAV (odor activity value) >1 were calculated using the odor activity value (OAV) of the threshold of the aromatic compound, and the OPLS-DA analysis was performed by orthogonal partial least squares discriminant analysis (OPLS-DA) using the OAV values of the compounds with OAV values >1 as the Y variable. The VIP (Variable Importance in Projection) values of six compounds, ethyl isobutyrate, ethyl hexanoate-D, 2-methylpropanal, ethyl octanoate, ethyl butanoate-D, and Isoamyl acetate-D, were calculated to be higher than one between groups, indicating that these six compounds may influence aroma differences. It is essential to recognize that the results of this study have implications for understanding the quality differences between different varieties of wines and for developing wines that have the characteristics of those varieties.

The higher alcohols 2-phenylethanol, tryptophol, and tyrosol are a group of yeast-derived compounds that have been shown to affect the aroma and flavour of fermented beverages. Five variants of the industrial wine strain AWRI796, previously isolated due to their elevated production of the ‘rose-like aroma’ compound 2-phenylethanol, were characterised during pilot-scale fermentation of a Chardonnay juice. We show that these variants not only increase the concentration of 2-phenylethanol but also modulate the formation of the higher alcohols tryptophol, tyrosol, and methionol, as well as other volatile sulfur compounds derived from methionine, highlighting the connections between yeast nitrogen and sulfur metabolism during fermentation. We also investigate the development of these compounds during wine storage, focusing on the sulfonation of tryptophol. Finally, the sensory properties of wines produced using these strains were quantified at two time points, unravelling differences produced by biologically modulating higher alcohols and the dynamic changes in wine flavour over aging.

This review intends to rationalize the knowledge related to the aroma of grapes and to the aroma of wine with specific origin in molecules formed in grapes. The actual flavor of grapes is formed by the few free aroma molecules already found in the pulp and in the skin, plus by those aroma molecules quickly formed by enzymatic/catalytic reactions. The review covers key aroma components of aromatic grapes, raisins and raisinized grapes, and the aroma components responsible from green and vegetal notes. This knowledge is used to explain the flavor properties of neutral grapes. The aroma potential of grape is the consequence of five different systems/pools of specific aroma precursors that during fermentation and/or aging, release wine varietal aroma. In total, 27 relevant wine aroma compounds can be considered that proceed from grape specific precursors. Some of them are immediately formed during fermentation, while some others require long aging time to accumulate. Precursors are glycosides, glutathionyl and cysteinyl conjugates, and other non-volatile molecules.

The influence of pre-fermentation cold maceration (CM) on Cabernet Sauvignon wines fermented in two different industrial-scale fermenters was studied. CM treatment had different effects on wine aroma depending on the types of fermenter, being more effective for automatic pumping-over tank (PO-tank) than automatic punching-down tank (PD-tank). When PO-tank was used, CM-treated wine showed a decrease in some fusel alcohols (isobutanol and isopentanol) and an increase in some esters (especially acetate esters). However, no significant changes were detected in these compounds when PD-tank was used. Ethyl 2-hexenoate and diethyl succinate were decreased, while geranylacetone was increased by the CM treatment in both fermenters. β-Damascenone was increased by the CM treatment in PO-tank fermented wines but decreased in PD-tank fermented wines. The fruity, caramel and floral aroma series were enhanced while chemical series were decreased by the CM treatment in PO-tank fermented wines. The content of (Z)-6-nonen-1-ol in the final wines was positively correlated to CM treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

The volatile compounds of mulberries obtained from three cultivars (M. nigra, Y1, M. Macroura, Y2 and M. Alba, Y3) were investigated by gas chromatography-olfactometry (GC-O), odor activity value (OAV), gas chromatography-mass spectrometry (GC-MS) and flame photometric detection (FPD). The results showed that 41, 37 and 41 compounds were detected in Y1, Y2 and Y3 samples, respectively. In addition, 12, 11, and 12 sulfur compounds were identified in three samples by FPD, respectively. Quantitative analysis showed 2-(methylthio)ethanol, methionol, dimethyl sulfide, methional and 3-ethylthiophene were present in relatively high amounts in each of the three samples. Furthermore, benzaldehyde, ethyl butanoate, (E)-2-nonenal, 1-hexanol, hexanal, methional, 3-mercaptohexyl acetate and 3-mercaptohexanol were present with much higher OAVs than other compounds. Finally, four compounds (pentanal, ethyl acetate, acetic acid, methionol) were selected to investigate possible effects on six descriptors, which indicated that the volatile compounds at sub-threshold concentrations are likely to contribute to overall aroma.Copyright © 2017 Elsevier Ltd. All rights reserved.

A method is being proposed in order to discriminate bottled wines of different varieties when no other information is known. The advantages of the method consist in the fact that anyone who wants to certify the variety, which is written on the label or the area of origin, can use such a technique to achieve the conformity. Additionally, the method can be easily applied by laboratories equipped with a GC. The differentiation has been achieved by using only seven of the total extracted volatiles, mainly higher alcohols and higher alcohol esters, namely 3-methyl-1-butanol, 2,3-butanediol, ethyl lactate, 3-methyl-1-butyl acetate, 2-phenylethanol, phenyl ethyl acetate and p-hydroxy phenyl ethanol. These key compounds are not relevant to a single variety. The proposed method does not take into account variables such as the year of vintage and fermentation procedures (agitation, temperature). Copyright © 2014 Elsevier Ltd. All rights reserved.

Wine is a complex matrix that includes components with different chemical natures, the volatile compounds being responsible for wine aroma quality. The microbial ecosystem of grapes and wine, including Saccharomyces and non-Saccharomyces yeasts, as well as lactic acid bacteria, is considered by winemakers and oenologists as a decisive factor influencing wine aroma and consumer’s preferences. The challenges and opportunities emanating from the contribution of wine microbiome to the production of high quality wines are astounding. This review focuses on the current knowledge about the impact of microorganisms in wine aroma and flavour, and the biochemical reactions and pathways in which they participate, therefore contributing to both the quality and acceptability of wine. In this context, an overview of genetic and transcriptional studies to explain and interpret these effects is included, and new directions are proposed. It also considers the contribution of human oral microbiota to wine aroma conversion and perception during wine consumption. The potential use of wine yeasts and lactic acid bacteria as biological tools to enhance wine quality and the advent of promising advice allowed by pioneering -omics technologies on wine research are also discussed.

2-Phenylethanol (2-PE) is widely used in food, perfume and pharmaceutical industry, but lower production in microbes and less known regulatory mechanisms of 2-PE make further study necessary. In this study, crucial genes like ARO8 and ARO10 of Ehrlich pathway for 2-PE synthesis and key transcription factor ARO80 in Saccharomyces cerevisiae were re-regulated using constitutive promoter; in the meantime, the effect of nitrogen source in synthetic complete (SC) medium with l-phenylalanine (l-Phe) on Aro8/Aro9 and Aro10 was investigated. The results showed that aromatic aminotransferase activities of ARO8 over-expressing strains were seriously inhibited by ammonia sulfate in SC + Phe medium. Flask fermentation test demonstrated that over-expressing ARO8 or ARO10 led to about 42 % increase in 2-PE production when compared with the control strain. Furthermore, influence of transcription factors Cat8 and Mig1 on 2-PE biosynthesis was explored. CAT8 over-expression or MIG1 deletion increased in the transcription of ARO9 and ARO10. 2-PE production of CAT8 over-expressing strain was 62 % higher than that of control strain. Deletion of MIG1 also led to 2-PE biosynthesis enhancement. The strain of CAT8 over-expression and MIG1 deletion was most effective in regulating expression of ARO9 and ARO10. Analysis of mRNA levels and enzyme activities indicates that transaminase in Ehrlich pathway is the crucial target of Nitrogen Catabolize Repression (NCR). Among the engineering strains, the higher 3.73 g/L 2-PE production in CAT8 over-expressing strain without in situ product recovery suggests that the robust strain has potentiality for commercial exploitation.

Wine produced at low temperature is often considered to have improved sensory qualities. To investigate the effects of temperature on winemaking, the expression patterns during the industrial fermentation process carried out at 13 degrees C and 25 degrees C were compared, and correlated with physiological and biochemical data, including viability, fermentation byproducts and lipid content of the cells. From a total of 535 ORFs that were significantly differentially expressed between the 13 degrees C and 25 degrees C fermentations, two significant transcription programmes were identified. A cold-stress response was expressed at the initial stage of the fermentation, and this was followed by a transcription pattern of upregulated genes concerned with the cell cycle, growth control and maintenance in the middle and late stages of the process at 13 degrees C with respect to 25 degrees C. These expression patterns were correlated with higher cell viability at low temperature. The other relevant transcriptomic difference was that several genes implicated in cytosolic fatty acid synthesis were downregulated, while those involved in mitochondrial short-chain fatty acid synthesis were upregulated in the fermentation process conducted at 13 degrees C with respect to that at 25 degrees C. These transcriptional changes were qualitatively correlated with improved resistance to ethanol and increased production of short-chain (C(4)-C(8)) fatty acids and their corresponding esters at 13 degrees C as compared to 25 degrees C. While this increase of ethyl esters may account in part for the improved sensory quality of wine fermented at 13 degrees C, it is still unclear how the esterification of the short-chain fatty acids takes place. On the basis of its strong upregulation at 13 degrees C, we propose a possible role of IAH1 encoding an esterase/ester synthase in this process.

Although there are many chemical compounds present in wines, only a few of these compounds contribute to the sensory perception of wine flavor. This review focuses on the knowledge regarding varietal aroma compounds, which are among the compounds that are the greatest contributors to the overall aroma. These aroma compounds are found in grapes in the form of nonodorant precursors that, due to the metabolic activity of yeasts during fermentation, are transformed to aromas that are of great relevance in the sensory perception of wines. Due to the multiple interactions of varietal aromas with other types of aromas and other nonodorant components of the complex wine matrix, knowledge regarding the varietal aroma composition alone cannot adequately explain the contribution of these compounds to the overall wine flavor. These interactions and the associated effects on aroma volatility are currently being investigated. This review also provides an overview of recent developments in analytical techniques for varietal aroma identification, including methods used to identify the precursor compounds of varietal aromas, which are the greatest contributors to the overall aroma after the aforementioned yeast-mediated odor release.

Acetic acid is undesired in Icewine. It is unclear whether its production by fermenting yeast is linked to the nicotinamide adenine dinucleotide (NAD+/NADH) system or the nicotinamide adenine dinucleotide phosphate (NADP+/NADPH) system. To answer this question, the redox status of yeast cytosolic NAD(H) and NADP(H) were analyzed along with yeast metabolites to determine how redox status differs under Icewine versus table wine fermentation. Icewine juice and dilute Icewine juice were inoculated with commercial wine yeast Saccharomyces cerevisiae K1-V1116. Acetic acid was 14.3-fold higher in Icewine fermentation than the dilute juice condition. The ratio of NAD+ to total NAD(H) was 24-fold higher in cells in Icewine fermentation than the ratio from the dilute juice condition. Conversely, the ratio of NADP+ to total NADP(H) from the dilute fermentation was 2.9-fold higher than that in the Icewine condition. These results support the hypothesis that in Icewine, increased NAD+ triggered the catalysis of NAD+-dependent aldehyde dehydrogenase(s) (Aldp(s)), which led to the elevated level of acetic acid in Icewine, whereas, in the dilute condition, NADP+ triggered NADP+-dependent Aldp(s), resulting in a lower level of acetic acid. This work, for the first time, analyzed the yeast cytosolic redox status and its correlation to acetic acid production, providing a more comprehensive understanding of the mechanism of acetic acid production in Icewine.

从新疆北麓产区的赤霞珠葡萄酒中筛选出3株乳酸菌,经16S rDNA鉴定,分别为酒酒球菌JN1(Oenococcus oeni)、植物乳杆菌ZN3(Lactobacillus plantarum)和干酪乳杆菌GN9(Lactobacillus casei)。以酒酒球菌JN1、植物乳杆菌ZN3、干酪乳杆菌GN9和商业菌株S1开启赤霞珠葡萄酒苹果酸-乳酸发酵(malolactic fermentation,MLF),并采用高效液相色谱技术和顶空固相微萃取结合气相色谱质谱联用(headspace solid-phase microextraction/gas chromatography-mass spectrometry,HS-SPME-GC-MS)技术检测葡萄酒的理化指标和香气物质,考察乳酸菌对赤霞珠葡萄酒品质的影响。结果表明,乳酸菌的MLF能力大小为：ZN3>S1>JN1>GN9,除GN9外,其他菌株参与发酵后均使香气物质的种类和含量有所增加。GN9酒样的特征性香气物质为丁内酯, JN1酒样的特征性香气物质为3-甲基丁酸、(E)- 3-己烯-1-醇、异戊醇和正己醇, ZN3酒样的特征性香气物质为癸醛、乙醛、正辛醇和3-甲基丁酸乙酯。相比商业菌株S1,3株乳酸菌为葡萄酒赋予了独特的风味,其中植物乳杆菌ZN3具有最强的MLF能力,能显著增加香气物质的种类和含量,赋予葡萄酒果香味、玫瑰味、脂肪味、咖啡香味和茴香味,在关键性香气分析和感官分析中均具有最优评价,具有进一步开发成商业发酵剂的潜力。

Malolactic fermentation (MLF) or biological decrease of wine acidity is defined as the enzymatic bioconversion of malic acid in lactic acid, a process performed by lactic acid bacteria (LAB). The procedures for the isolation of new indigenous LAB strains from the red wines produced in Copou Iasi wine center (NE of Romania) undergoing spontaneous malolactic fermentation, resulted in the obtaining of 67 catalase-negative and Gram-positive LAB strains. After testing in the malolactic fermentative process, application of specific screening procedures and identification (API 50 CH), two bacterial strains belonging to the species Oenococcus oeni (strain 13-7) and Lactobacillus plantarum (strain R1-1) with high yield of malolactic bioconversion, non-producing biogenic amines, and with active extracellular enzymes related to wine aroma, were retained and characterized. Tested in synthetic medium (MRS-TJ) for 10 days, the new isolated LAB strains metabolized over 98% of the malic acid at ethanol concentrations between 10 and 14 % (v/v), low pH (>3.0), total SO2 doses up to 70 mg/L and temperatures between 15 and 35 °C, showing high potential for future use in the winemaking process as bacterial starter cultures, in order to obtain high quality wines with increased typicity.

为解决葡萄酒专用乳酸菌依赖国外进口,导致葡萄酒品质同质化严重的问题,以甘肃河西走廊产区处于自然苹果酸-乳酸发酵(苹乳发酵)的葡萄酒为来源,筛选具有本土特色的优势乳酸菌。通过改良MRS培养基分离乳酸菌,经生理生化、16S rDNA基因同源性分析等鉴定,并对筛选菌株进行酿酒特性分析。获得3株具有启动苹乳发酵的小片球菌(Pediococcus parvulus,P.parvulus)且均具有较强的降酸能力,较商品乳酸菌差异不显著,其中菌株C30在低温(15 ℃)、高乙醇体积分数(14%)和高SO₂质量浓度(50 mg/L)条件下的生物量显著高于商品乳酸菌。菌株C30可作为启动苹乳发酵的优势菌株,对提升河西走廊产区葡萄酒品质具有一定的应用潜力,在一定程度上推动葡萄酒品质同质化问题的解决。

该研究利用高通量测序技术分析了宁夏贺兰山东麓4个葡萄产区中30个酿酒葡萄微生物组成和多样性。结果表明,在属水平上,无论是细菌多样性,还是真菌多样性,产区间都存在明显差异;赤霞珠葡萄品种最为丰富的真菌属为Alternaria、Cladosporium、Fusarium、Chaetomium和Didymella,细菌的优势菌为Ralstonia、unidentified_Chloroplast、Massilia、Gluconobacter和Sphingomonas;产区距离相距越远,微生物相似度也越低。霞多丽中真菌的优势菌为Alternaria、Cladosporium、Naganshia、Hanseniaspora和Aspergillus,细菌的优势菌为Serratia、Ralstonia、Pantoea、unidentified_Chloroplast和Pseudomonas;同产区不同酿酒葡萄品种采收期越晚,真菌微生物种类也越多,而细菌的多样性却越低。

The biodiversity of lactic acid bacteria in musts and wines of Albariño variety has been studied. The identification of species was addressed through a combination of biochemical and genetic methods (API® 50 CHL test, 16S rDNA and recA gene sequences, Amplified Ribosomal DNA Restriction Analysis -ARDRA- and 16S-26S intergenic region analysis). The results grouped the isolates into six species predominating those of the genus Lactobacillus and showing a typical biogeographical distribution. Among sixteen strains evaluated, eight of them showed malolactic activity. The study of the presence of genes hdc, odc, and tdc, along with the LC/MS-MS analysis of biogenic amines in wine, showed five strains lacking aminogenic ability. The absence of the pad gene in the above-mentioned strains discards its ability to produce volatile phenols that may adversely affect the aroma. Finally, all malolactic strains showed β-glucosidase activity so that they could contribute to enhance and differentiate the aromatic profile of Albariño wines.

Lactic acid bacteria are very important in winemaking. In this study, 108 lactic acid bacteria isolates were obtained from high-ethanol-content (~17% (v/v)) Grenache wines during uninoculated malolactic fermentation (MLF). The 16S rRNA and species-specific PCR showed that 104 of these were Oenococcusoeni, three were Lactobacillus hilgardii, and one was Staphylococcus pasteuri. AFLP of HindIII and MseI digests of the genomic DNA of the O. oeni strains was developed for the first time to discriminate the strains. The results showed that the method was a suitable technique for discriminating the O. oeni strains. Based on the cluster analysis, nine O. oeni strains were chosen for inclusion in an ethanol tolerance assay involving monitoring of optical density (ABS600nm) and viable plating. Several O. oeni strains (G63, G46, G71, G39) survived and grew well in MRS-AJ with 17% (v/v) ethanol, while the commercial O. oeni reference strain did not. Strain G63 could also survive and grow for 168 h after inoculation in MRS-AJ medium with 19% (v/v) ethanol. These results suggest that O. oeni G63, G46, G71, and G39 could potentially be used as MLF starters for high-ethanol-content wines. All three L. hilgardii strains could survive and grow in MRS-AJ with 19% (v/v) ethanol, perhaps also indicating their suitability as next-generation MLF starter cultures.

Due to changes in climatic conditions in Poland interest in viticulture and wine production has considerably boosted. One of the worldwide trends in winemaking is use of indigenous strains of yeast and lactic acid bacteria (LAB). The aim of the study was to analyse the microbial diversity of Polish red wines and their key properties and combine them for better understanding of the processes responsible for creating the sensory attributes. Metagenetic analysis was used to characterise the bacterial and yeast diversity of wines produced by spontaneous fermentation of grapes of the Regent variety, which came from three vineyards: “Dom Bliskowice” (DB), “Małe Dobre” (MD), and “Winnica Janowiec” (WJ). Among bacteria, Tatumella ptyseos was the most abundant species in DB and WJ wines and Leuconostoc pseudomesenteroides was the most abundant in MD wine. Among yeasts, Saccharomyces cerevisiae was found in DB and WJ wines, Saccharomyces cariocanus in MD wine, and Hanseniaspora uvarum in all samples studied. Studied wines had statistically significantly different antioxidant capacities and distinct glucose, fructose, and lactic acid concentrations. The presence of acetic and lactic acid bacteria was positively related to the concentrations of acetic and lactic acid, respectively, while the lack of malic acid was indicative of malolactic fermentation. This knowledge may be useful in the development of unique local starter cultures for the production of wines with specific characteristics.

Wine fermentation processes are driven by complex microbial systems, which comprise eukaryotic and prokaryotic microorganisms that participate in several biochemical interactions with the must and wine chemicals and modulate the organoleptic properties of wine. Among these, yeasts play a fundamental role, since they carry out the alcoholic fermentation (AF), converting sugars to ethanol and CO2 together with a wide range of volatile organic compounds. The contribution of Saccharomyces cerevisiae, the reference organism associated with AF, has been extensively studied. However, in the last decade, selected non-Saccharomyces strains received considerable commercial and oenological interest due to their specific pro-technological aptitudes and the positive influence on sensory quality. This review aims to highlight the inter-specific variability within the heterogeneous class of non-Saccharomyces in terms of synthesis and release of volatile organic compounds during controlled AF in wine. In particular, we reported findings on the presence of model non-Saccharomyces organisms, including Torulaspora delbrueckii, Hanseniaspora spp,Lachancea thermotolerans, Metschnikowia pulcherrima, Pichia spp. and Candida zemplinina, in combination with S. cerevisiae. The evidence is discussed from both basic and applicative scientific perspective. In particular, the oenological significance in different kind of wines has been underlined.

酒类酒球菌是触发葡萄酒苹果酸-乳酸发酵(malolactic fermentation，MLF)的主要乳酸菌，其代谢产物如乳酸、乙酸、双乙酰、乙偶姻、生物胺等对葡萄酒的感官品质有重要作用。本文对酒类酒球菌在葡萄酒MLF过程的代谢情况进行总结，阐述糖、有机酸、含氮物质和酚类化合物的代谢情况，以及在不同影响因素下酒类酒球菌生长和代谢途径的改变状况，已经证明pH值、SO2、乙醇体积分数、葡萄糖/果糖比等都是影响代谢的因素。随着研究的不断深入，酚类化合物在代谢中的作用也受到越来越多的关注。酚类化合物一方面通过刺激或者抑制酒类酒球菌的生长而间接影响MLF的进行；另一方面，不同的酚类物质也会影响细菌对其他酚类的代谢，从而影响葡萄酒的口感和质量。通过全面综合了解酒类酒球菌在葡萄酒中的代谢情况有助于更好地调控MLF过程。

Malolactic fermentation (MLF) in wine is an important step in the vinification of most red and some white wines, as stands for the biological conversion of l-malic acid into l-lactic acid and carbon dioxide, resulting in a decrease in wine acidity. MLF not only results in a biological deacidification, it can exert a significant impact on the organoleptic qualities of wine. This paper reviews the biodiversity of lactic acid bacteria (LAB) in wine, their origin, and the limiting conditions encountered in wine, which allow only the most adapted species and strains to survive and induce malolactic fermentation. Of all the species of wine LAB, Oenococcus oeni is probably the best adapted to overcome the harsh environmental wine conditions and therefore represents the majority of commercial MLF starter cultures. Wine pH is most challenging, but, as a result of global warming, Lactobacillus sp. is more often reported to predominate and be responsible for spontaneous malolactic fermentation. Some Lactobacillus plantarum strains can tolerate the high alcohol and SO2 levels normally encountered in wine. This paper shows the potential within this species for the application as a starter culture for induction of MLF in juice or wine. Due to its complex metabolism, a range of compositional changes can be induced, which may positively affect the quality of the final product. An example of a recent isolate has shown most interesting results, not only for its capacity to induce MLF after direct inoculation, but also for its positive contribution to the wine quality. Degrading hexose sugars by the homo-fermentative pathway, which poses no risk of acetic acid production from the sugars, is an interesting alternative to control MLF in high pH wines. Within this species, we can expect more strains with interesting enological properties.