Project description:Propionibacterium freudenreichii, a dairy starter, reaches a population close to 10^9 propionibacteria per gram of Swiss-type cheese at the time of consumption. Also consumed as a probiotic, it revealed strain-dependent anti-inflammatory properties mediated by proteins inducing IL-10 in leukocytes. Here, strains with varied anti-inflammatory potentials were compared in terms of transcriptome profiles.
Project description:The enzymatic repertoire of starter cultures is important for cheese characteristics but is challenging to characterize due to the high protein and fat concentration, and the semi-solid state of the cheese matrix. This study aimed to generate a protocol to characterize the proteome of bacteria harvested from milk and cheese, to assess the proteome differences between Lactococcus cremoris grown in milk and laboratory medium, and to investigate the proteome adaptation during cheese production and ripening.
2025-03-12 | PXD046375 | Pride
Project description:RNA-seq of cheese starter cultures
Project description:This study investigated the impact of individual lactococcal starter cultures on peptide formation and bitter peptide accumulation during cheese aging using a novel mini-scale cheese production system. Cheeses were produced using single-strain fermentations of Lactococcus lactis and Lactococcus cremoris and aged for 45 and 90 days. Peptide profiles were analyzed using LC-MS/MS-based peptidomics to characterize strain-specific proteolytic patterns and bitter peptide generation from casein proteins. The resulting peptide profiles demonstrated strong strain specificity and reproducibility among replicates. Particular emphasis was placed on bitter peptides derived from β-casein and αS1-casein regions associated with cheese bitterness. Two L. lactis strains, E2-4M12 and E1-6M12, consistently produced lower abundances of bitter peptides despite substantial overall peptide abundance, suggesting unique proteolytic characteristics. Comparative analysis between CEP-positive and CEP-negative strains indicated that CEP genotype alone was not a primary determinant of bitter peptide accumulation. These findings contribute to understanding how starter culture selection influences cheese proteolysis and bitterness development during ripening.
Project description:Propionibacterium freudenreichii is an important starter culture used in the manufacture of Swiss-type cheeses. We have generated the complete genome sequence of a Propionibacterium freudenreichii ssp. shermanii strain JS at the Institute of Biotechnology, University of Helsinki, by using a combination of pyrosequencing with GS FLX and GS FLX Titanium series reagents (Roche) and SOLiD 4 (Life Technologies), ABI 3130xl Genetic Analyzer (Life Technologies), and PacBio RS II (Pacific Biosciences) instruments. Initial genome annotation was carried out using RAST, and additional functional annotation information for each CDS was obtained from BLANNOTATOR, CDD, and KAAS. Accession number for genome sequence is PRJEB12148. This submission is for the transcriptome analysis of Propionibakcterium freudenreichii in cheese ripening under warm and cold conditions. The RNA reads were mapped to the reference genome PRJEB12148.
