Veronica Vendramin

Whole-Genome Sequences of Streptococcus thermophilus Strains TH1435 and TH1436, Isolated from Raw Goat Milk.

ABSTRACT We report the genome sequences of two Streptococcus thermophilus strains, TH1435 and TH1436, isolated from raw goat milk devoted to the production of artisanal cheese in the Friuli-Venezia Giulia region in Italy. The genome sequences of these two quickly acidifying strains are the first available genome sequences of S. thermophilus strains isolated in Italy.

Genome Sequences of Four Italian Streptococcus thermophilus Strains of Dairy Origin

ABSTRACT This report describes the genome sequences of four Streptococcus thermophilus strains, namely, TH982, TH985, TH1477, and 1F8CT, isolated from different dairy environments from the Campania and the Veneto regions in Italy. These data are aimed at increasing the genomic information available on this species, which is of paramount importance for the dairy industry.

In vitro fermentation of key dietary compounds with rumen fluid: A genome-centric perspective.

The anaerobic decomposition of organic substrates leads to the generation of gases, such as methane, which can either be a valuable energy carrier in industrial applications or can be considered as a main greenhouse gas when it is naturally emitted. In this study we investigated in vitro the effect of dietary compounds, such as starch and proteins, on the microbial community present in the rumen fluid. High throughput shotgun sequencing, followed by metagenomic assembly and binning allowed the extraction of 18 genome bins. A composite bioinformatic analysis led to the prediction of metabolic pathways involved in the degradation of dietary compounds and in the biosynthesis of crucial products like propionate, methane and ammonia. The identification of genomes belonging to poorly characterized phyla such as Thermoplasmata and Elusimicrobia shed light on their putative role. The high abundance of methylotrophic archaea in the inoculum suggests a relevant role in methane production.

Whole-Genome Sequence of Streptococcus macedonicus Strain 33MO, Isolated from the Curd of Morlacco Cheese in the Veneto Region (Italy)

ABSTRACT A genetic characterization of Streptococcus macedonicus is important to better understand the characteristics of this lactic acid bacterium, frequently detected in fermented food bacteria communities. This report presents the draft genome sequence description of strain 33MO, the first publicly available genome sequence of an Italian S. macedonicus isolate.

Genome Sequence of Lactobacillus fabifermentans Strain T30PCM01, Isolated from Fermenting Grape Marc.

ABSTRACT Here, we report the draft genome assembly of Lactobacillus fabifermentans strain T30PCM01 isolated from grape marc. Its genome is the largest (3.58 Mbp) among Lactobacillus species and reveals an enormous potential for carbohydrate utilization and transcriptional regulation.

Potential use of scotta, the by-product of the ricotta cheese manufacturing process, for the production of fermented drinks.

In the present work, the use of scotta as substrate for bacterial fermentation was studied with the objective of obtaining a drink from transformation of this by-product. Scotta retains most of the lactose of the milk and it is normally colonized by a natural microbiota. A treatment was devised to reduce the autochthonous microbial populations in order to reduce competition towards the inoculated bacterial strains. Nine lactic acid bacteria (LAB) were assessed for their capability to develop in scotta. They evidenced different behaviors regarding growth rate, acidification capability and nitrogen consumption. A co-inoculum of three LAB, namely a Streptococcus thermophilus, a Lactobacillus delbrueckii subsp. bulgaricus and a Lb. acidophilus strains, chosen among those giving the best performances in single-strain fermentation trials, gave abundant (close to 10(9) cfu/ml) and balanced growth and lowered pH to 4.2, a value similar to that of yogurt. These results show that scotta may have potential as a substrate for bacterial growth for the production of a fermented drink. Further studies are needed to optimize the organoleptic aspects of the final product.

Comparative Transcriptomic Analysis of Streptococcus thermophilus TH1436 and TH1477 Showing Different Capability in the Use of Galactose

Streptococcus thermophilus is a species widely used in the dairy industry for its capability to rapidly ferment lactose and lower the pH. The capability to use galactose produced from lactose hydrolysis is strain dependent and most of commercial S. thermophilus strains are galactose-negative (Gal−), although galactose-positive (Gal+) would be more technologically advantageous because this feature could provide additional metabolic products and prevent galactose accumulation in foods. In this study, a next generation sequencing transcriptome approach was used to compare for the first time a Gal+ and a Gal− strain to characterize their whole metabolism and shed light on their different properties, metabolic performance and gene regulation. Transcriptome analysis revealed that all genes of the gal operon were expressed very differently in Gal+ and in the Gal− strains. The expression of several genes involved in mixed acid fermentation, PTS sugars transporter and stress response were found enhanced in Gal+. Conversely, genes related to amino acids, proteins metabolism and CRISPR associated proteins were under-expressed. In addition, the strains showed a diverse series of predicted genes controlled by the transcriptional factor catabolite control protein A (CcpA). Overall, transcriptomic analysis suggests that the Gal+ strain underwent a metabolic remodeling to cope with the changed environmental conditions.