0000000000178396
AUTHOR
Yaiza Benavent-gil
A novel culture medium for Oenococcus oeni malolactic starter production
Malolactic fermentation is essential in wine quality. One of the strategies used to control this fermentation involves the inoculation of selected lactic acid bacteria, mainly Oenococcus oeni. Laboratory media usually produce large amounts of biomass, but with little or no adaptability to wine. We propose a culture medium to grow and pre-adapt O. oeni cells, and the steps to scale-up production. To achieve this objective, 27 different media were tested. All contained grape must and wine, and nutritional supplements in order to benefit bacterial growth. Those media contained different ethanol levels, pH values, and grape must concentrations. The optimized culture medium named Oenococcus Prod…
Genome structure reveals the diversity of mating mechanisms in Saccharomyces cerevisiae x Saccharomyces kudriavzevii hybrids, and the genomic instability that promotes phenotypic diversity
Interspecific hybridization has played an important role in the evolution of eukaryotic organisms by favouring genetic interchange between divergent lineages to generate new phenotypic diversity involved in the adaptation to new environments. This way, hybridization between Saccharomyces species, involving the fusion between their metabolic capabilities, is a recurrent adaptive strategy in industrial environments. In the present study, whole-genome sequences of natural hybrids between Saccharomyces cerevisiae and Saccharomyces kudriavzevii were obtained to unveil the mechanisms involved in the origin and evolution of hybrids, as well as the ecological and geographic contexts in which sponta…
Acetobacter musti sp. nov., isolated from Bobal grape must
An acetic acid bacterium (strain Bo7T), obtained during a study of the microbial diversity of spontaneous fermentations of Bobal grape must, was subjected to a taxonomic study using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences allocated strain Bo7T to the genus Acetobacter, and revealed Acetobacter aceti and Acetobacter oeni to be nearest neighbours (99.57 % 16S rRNA gene sequence similarity between strain Bo7T and A. oeni CECT 5830T, and 98.76 % between strain Bo7T and A. aceti CECT 298T). Cells of strain Bo7T are Gram-negative, motile rods, catalase-positive and oxidase-negative. The DNA G+C content of strain Bo7T was 58.0 mol%. DNA–DNA hybridizations demo…
A new fear in wine: Isolation of Staphylococcus epidermidis histamine producer
Abstract Biogenic amines (BAs) are undesirable compounds in all foods and beverages because they may induce food-borne intoxications when consumed at high concentrations. The aim of this study was to identify the organism responsible for the synthesis of histamine in a Tempranillo red wine from Ribera de Duero D.O. (Denomination of origin), Spain. Bacteria present in wines after malolactic fermentation were isolated, identified and typed. Four strains of the species Oenococcus oeni and two strains of Staphylococcus epidermidis were found. None of the O. oeni strains produced histamine, cadaverine or putrescine, but one of the S. epidermidis strains (Pa) was able to produce all three in synt…
Lowering histamine formation in a red Ribera del Duero wine (Spain) by using an indigenous O. oeni strain as a malolactic starter
This study demonstrates for the first time that a non-commercial selected autochthonous O. oeni strain has been used to conduct malolactic fermentation (MLF) while lowering histamine formation in the same winery. Lactic acid bacteria (LAB) were isolated from 13 vats before and after spontaneous MLF at the Pago de Carraovejas winery from the Ribera del Duero region (Spain). Only O. oeni were present, typed and characterized, and both histamine producer and non-producers existed. From the non-producers, one strain was selected to become a starter according to its genetic profile, prevalence in the different wines in the winery, resistance to alcoholic degree, resistance to high polyphenolic c…