Functional Divergence in the Genus Oenococcus as Predicted by Genome Sequencing of the Newly-Described Species, Oenococcus kitaharae

Oenococcus kitaharae is only the second member of the genus Oenococcus to be identified and is the closest relative of the industrially important wine bacterium Oenococcus oeni. To provide insight into this new species, the genome of the type strain of O. kitaharae, DSM 17330, was sequenced. Comparison of the sequenced genomes of both species show that the genome of O. kitaharae DSM 17330 contains many genes with predicted functions in cellular defence (bacteriocins, antimicrobials, restriction-modification systems and a CRISPR locus) which are lacking in O. oeni. The two genomes also appear to differentially encode several metabolic pathways associated with amino acid biosynthesis and carbohydrate utilization and which have direct phenotypic consequences. This would indicate that the two species have evolved different survival techniques to suit their particular environmental niches. O. oeni has adapted to survive in the harsh, but predictable, environment of wine that provides very few competitive species. However O. kitaharae appears to have adapted to a growth environment in which biological competition provides a significant selective pressure by accumulating biological defence molecules, such as bacteriocins and restriction-modification systems, throughout its genome

Ecology and technological capability of lactic acid bacteria isolated during Grillo grape vinification in the Marsala production area.

Grapes of “Grillo” variety, used to produce Marsala wine, were harvested from five vineyards different for climatic and agronomic parameters, in order to obtain a first mapping of lactic acid bacteria (LAB) inhabiting the production area. Marsala base wine production was followed at large-scale and two experimental vinifications, different for lysozyme and SO2 concentration and combination, were carried out at pilot-plant scale. LAB communities and conventional chemical parameters were periodically analysed. LAB were found on grapes at an average concentration of about 102 CFU g-1 which decreased during the transformation process. A total of 146 colonies were collected, but only 35 were recognized as presumptive LAB. On the basis of phenotypic differences and isolation source, 16 isolates were then subjected to genotypic identification and gathered into the following species: Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. cremoris, Enterococcus faecium, Leuconostoc fallax and Sporalactobacillus nakayamae subsp. nakayamae. Lactococcus lactis subsp. lactis strains was the species most frequently isolated during winemaking showing the highest resistance to SO2 and lysozyme

Oenological characterisation of indigenous strains of S. cerevisiae isolated in a biodynamic winery in the Cortona DOC area

Genotypic and technological characterisation of the S. cerevisiae population isolated in a biodynamic winery in the Cortona DOC area was performed to gain better knowledge of the variables that influence winemaking. The oenological performance of 11 S. cerevisiae strains was evaluated with physiological tests; strain typing was performed through analysis of interdelta sequences and 26S rDNA sequencing. The analysis revealed a remarkable variability in terms of S. cerevisiae strains, despite the homogeneity of wine features, underlining the high levels of biodiversity characterising biodynamic agriculture. Some strains were found in wines of different vintages, suggesting the presence of an established microbiota in the winery. Oenological tests demonstrated that while some yeasts provided reliable oenological performance, other strains were not able to accomplish prompt and effective alcoholic fermentation, or were characterised by spoilage characteristics, such as excessive production of volatile phenols or acetic acid. Indigenous strains of S. cerevisiae could be a useful instrument for reliable winemaking without altering the native microbiota of each oenological environment. However, characterisation of their oenological suitability, and the application of practices able to drive the evolution of microbiota, must be employed to reduce the risk of wine spoilage

Acetic Acid Bacteria: Physiology and Carbon Sources Oxidation

Acetic acid bacteria (AAB) are obligately aerobic bacteria within the family Acetobacteraceae, widespread in sugary, acidic and alcoholic niches. They are known for their ability to partially oxidise a variety of carbohydrates and to release the corresponding metabolites (aldehydes, ketones and organic acids) into the media. Since a long time they are used to perform specific oxidation reactions through processes called “oxidative fermentations”, especially in vinegar production. In the last decades physiology of AAB have been widely studied because of their role in food production, where they act as beneficial or spoiling organisms, and in biotechnological industry, where their oxidation machinery is exploited to produce a number of compounds such as l-ascorbic acid, dihydroxyacetone, gluconic acid and cellulose. The present review aims to provide an overview of AAB physiology focusing carbon sources oxidation and main products of their metabolism

Genotypic diversity in Oenococcus oeni by high-density microarray comparative genome hybridization and whole genome sequencing

Many bacteria display substantial intra-specific genomic diversity that produces significant phenotypic variation between strains of the same species. Understanding the genetic basis of these strain-specific phenotypes is especially important for industrial microorganisms where these characters match individual strains to specific industrial processes. Oenococcus oeni, a bacterium used during winemaking, is one such industrial species where large numbers of strains show significant differences in commercially important industrial phenotypes. To ascertain the basis of these phenotypic differences, the genomic content of ten wine strains of O. oeni were mapped by array-based comparative genome hybridization (aCGH). These strains comprised a genomically diverse group in which large sections of the reference genome were often absent from individual strains. To place the aCGH results in context, whole genome sequence was obtained for one of these strains and compared with two previously sequenced, unrelated strains. While the three strains shared a core group of conserved ORFs, up to 10% of the coding potential of any one strain was specific to that isolate. The genome of O. oeni is therefore likely to be much larger than that present in any single strain and it is these strain-specific regions that are likely to be responsible for differences in industrial phenotypes.Anthony R. Borneman, Eveline J. Bartowsky, Jane McCarthy, Paul J. Chamber

Histamine in Australian wines - a survey between 1982 and 2009

Biogenic amines are found in a range of fermented foods and beverages, including wine. Absorption of these compounds in elevated concentrations may induce headaches, gastro-intestinal and respiratory distress. The main biogenic amines found in wine are histamine, tyramine, cadaverine and putrescine. Even though concentrations of histamine in wine are generally ten-fold lower than found in some fresh and other fermented foods, their presence may contribute to an adverse reaction when consumed in combination with other histamine-containing foods. It is well established that the main contribution of biogenic amines in wines is from lactic acid bacteria metabolism, especially during or after malolactic fermentation (MLF). A survey for histamine content of Australian red and white wines produced during 1982–1990 demonstrated a wide range of concentrations (mean 1.58 and 0.21 mg/L, respectively). A second survey of histamine content in red and white wines produced during 2003–2009 (mean 1.75 and 0.59 mg/L, respectively) showed that there were minimal changes in the mean histamine concentration over the period of the two sets of wines. All 238 Australian wines from 1982–1990 and 99 of 100 wines from 2003–2009 were below the former regulatory recommended limit of 10 mg/L for histamine in wine and were low compared to other wine-producing countries. Seven other biogenic amines measured in the Australian wines from 2003–2009 also had low means compared to other wine-producing countries.Eveline J. Bartowsky and Creina S. Stockle