Finding a correct species assignment for a Metschnikowia strain: insights from the genome sequencing of strain DBT012.

Metschnikowia pulcherrima is an important yeast species that is attracting increased interest thanks to its biotechnological potential, especially in agri-food applications. Phylogenetically related species of the so-called 'pulcherrima clade' were first described and then reclassified in one single species, which makes the identification an intriguing issue. Starting from the whole-genome sequencing of the protechnological strain Metschnikowia sp.

Reconstruction of Simplified Microbial Consortia to Modulate Sensory Quality of Kombucha Tea.

Kombucha is a fermented tea with a long history of production and consumption. It has been gaining popularity thanks to its refreshing taste and assumed beneficial properties. The microbial community responsible for tea fermentation-acetic acid bacteria (AAB), yeasts, and lactic acid bacteria (LAB)-is mainly found embedded in an extracellular cellulosic matrix located at the liquid-air interphase.

Investigating the biotechnological potential of lactic acid bacteria strains isolated from different Algerian dairy and farm sources.

Currently, consumption of spontaneously fermented milks is common in Algeria, making it a feasible source of diverse lactic acid bacteria (LAB) with the potential to be used as adjunct cultures to improve quality and safety of fermented dairy products. In this context, to select eligible indigenous strains which could be applied as bioprotective and/or starter cultures, the present study aimed to characterize the genomic variability, biotechnological potential, and safety of thirty-eight LAB isolated from Algerian dairy and farm sources of western Algeria. The isolates were unequivocally identified by 16S rRNA gene and fingerprint-based methods.

New insights into the variability of lactic acid production in Lachancea thermotolerans at the phenotypic and genomic level.

Non-conventional yeasts are increasingly applied in fermented beverage industry to obtain distinctive products with improved quality. Among these yeasts, Lachancea thermotolerans has multiple features of industrial relevance, especially the production of l(+)-lactic acid (LA), useful for the biological acidification of wine and beer. Since few information is available on this peculiar activity, the current study aimed to explore the physiological and genetic variability among L.

Exploring the diversity of a collection of native non-Saccharomyces yeasts to develop co-starter cultures for winemaking.

The inoculation of Saccharomyces cerevisiae starter cultures in grape musts is a common practice in wineries worldwide; however, native non-Saccharomyces yeast species are increasingly investigated as co-starters to augment the complexity and regionality of wine. In this study, an extensive collection of non-Saccharomyces yeasts from high-sugar matrices was created and screened with the aim to discover new strains with potentially positive oenological traits. After mining >400 yeasts from 167 samples collected across multiple Italian regions, the isolates were identified based on RAPD-PCR analysis and ITS sequencing.

Antimicrobial spectrum activity of bacteriocinogenic Staphylococcus strains isolated from goat and sheep milk.

Bacteriocins have attracted great attention as potential alternatives to antibiotics and chemical food additives. In the present study, 243 Staphylococcus isolates from milk samples (n = 110) of goat and sheep herds located in Fars province, Iran, were screened for antimicrobial substance production. Twenty-eight isolates showed an antagonistic activity against the indicator strain Micrococcus luteus ATCC 4698.

Safety hazards in bacteriocinogenic Staphylococcus strains isolated from goat and sheep milk.

In this study, 28 bacteriocinogenic Staphylococcus strains isolated from goat and sheep milk were subjected to the PCR detection of enterotoxin genes (sea-see), enterotoxin-like toxin Q gene (selq), toxic shock syndrome toxin gene (tst1), and antibiotic resistance genes. They were also evaluated for phenotypic resistance against 10 antibiotics and hemolytic activity. The tyramine and histamine production was investigated using the agar plate assay and capillary zone electrophoretic analysis (CZE).

Tyrosine decarboxylase activity of Enterococcus mundtii: new insights into phenotypic and genetic aspects.

Few information is available about the tyraminogenic potential of the species Enterococcus mundtii. In this study, two plant-derived strains of E. mundtii were selected and investigated to better understand the phenotypic behaviour and the genetic mechanisms involved in tyramine accumulation.

Draft Genome Sequence of the Probiotic Yeast Kluyveromyces marxianus fragilis B0399.

Here, we report the draft genome sequence of Kluyveromyces marxianus fragilis B0399, the first yeast approved as a probiotic for human consumption not belonging to the genus Saccharomyces The genome is composed of 8 chromosomes, with a total size of 11.44 Mb, including mitochondrial DNA.

The Capability of Tyramine Production and Correlation between Phenotypic and Genetic Characteristics of Enterococcus faecium and Enterococcus faecalis Strains.

The aim of this study was to investigate the diversity of tyramine production capability of four Enterococcus strains in buffered systems in relation to their genetic characteristics and environmental conditions. Cells of the strains Enterococcus faecalis EF37 and ATCC 29212, and E. faecium FC12 and FC643 were re-suspended in phosphate/citrate buffers with different pH, NaCl concentration and incubation temperature.

Tyrosine decarboxylase activity of enterococci grown in media with different nutritional potential: tyramine and 2-phenylethylamine accumulation and tyrDC gene expression.

The ability to accumulate tyramine and 2-phenylethylamine by two strains of Enterococcus faecalis and two strains Enterococcus faecium was evaluated in two cultural media added or not with tyrosine. All the enterococcal strains possessed a tyrosine decarboxylase (tyrDC) which determined tyramine accumulation in all the conditions tested, independently on the addition of high concentration of free tyrosine. Enterococci differed in rate and level of biogenic amines accumulation.

Control of tyramine and histamine accumulation by lactic acid bacteria using bacteriocin forming lactococci.

The aim of this study was to evaluate the competitive effects of three bacteriocin producing strains of Lactococcus lactis subsp. lactis against two aminobiogenic lactic acid bacteria, i.e.

Modeling the aminogenic potential of Enterococcus faecalis EF37 in dry fermented sausages through chemical and molecular approaches.

Amino acid decarboxylase activity of the Enterococcus faecalis strain EF37 was monitored during fermentation and ripening of a traditional dry fermented sausage from Northern Italy (Salame Veronese) by means of microbiological, chemical, and molecular approaches in relation to three technological factors: fermentation temperature, sodium chloride concentration, and amount of glucose added to the meat mixture. Besides the analytical determination of tyramine and phenylethylamine accumulation and the counts of enterococci, the presence and quantification of the tyrosine decarboxylase gene (tdc) and its mRNA transcript were also investigated by using real-time PCR. According to the mathematical models obtained, all of the three factors studied were statistically significant and microbiologically relevant for the early development of enterococci, although the fermentation temperature had a more relevant influence on the enterococcal viable cells of the ripened product.

Rapid detection and quantification of tyrosine decarboxylase gene (tdc) and its expression in gram-positive bacteria associated with fermented foods using PCR-based methods.

In this study, PCR-based procedures were developed to detect the occurrence and quantify the expression of the tyrosine decarboxylase gene (tdc) in gram-positive bacteria associated with fermented foods. Consensus primers were used in conventional and reverse transcription PCR to analyze a collection of 87 pure cultures of lactic acid bacteria and staphylococci. All enterococci, Staphylococcus epidermidis, Lactobacillus brevis, Lactobacillus curvatus, and Lactobacillus fermentum strains and 1 of 10 Staphylococcus xylosus strains produced amplification products with the primers DEC5 and DEC3 in accordance with results of the screening plate method and with previously reported result obtained with high-performance liquid chromatography.

A genetic insight into peptide and amino-acid utilization by Propionibacterium freudenreichii LMG 16415.

In this note the genetic characterization of the peptide degrading system of Propionibacterium freudenreichii was addressed. Genomic fragments of P. freudenreichii subsp.