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Propionibacterium freudenreichii is a traditional Swiss-type cheeses starter and constitutes an emergent probiotic, exerting several beneficial effects, including anti-inflammatory modulation of gut inflammation. This feature relies on several metabolites and on surface proteins, with a prominent role of the surface protein SlpB. In this study, we firstly investigated the relevance to avoid SlpB digestive proteolysis, by comparing the effect of i) P. freudenreichii CIRM-BIA 129, ii) its native Slps, or iii) peptides resulting from Slps digestive proteolysis, with respect to modulation of HT-29 cells response to a lipopolysaccharide (LPS) challenge. The anti-inflammatory effect exerted by P. freudenreichii CIRM-BIA 129 and by its native surface proteins (Slps) on HT-29 cells was abolished by digestive proteolysis. This result confirmed the importance to protect immunomodulatory surface proteins from digestive proteolysis in order to allow gut immune system modulation. Thus, we examined the effect of dairy matrices on P. freudenreichii viability and on SlpB integrity during digestion. In comparison with liquid matrices, the cheese matrix provided an enhanced tolerance towards digestive stresses and protection of SlpB towards proteolysis, during two in vitro digestion models: static and dynamic. Taken together, these results show that cheese is an adequate delivery vehicle for P. freudenreichii immunomodulatory proteins. This opens perspectives for the development of fermented dairy functional foods aimed at target populations at high risk for diet-related diseases with an inflammatory component., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Dairy propionibacteria are actinomycetales found in various fermented food products. The main species, Propionibacterium freudenreichii, is generally recognized as safe and used both as probiotic and as cheese starter. Its probiotic efficacy tightly depends on its tolerance towards digestive stresses, which can be largely modulated by the ingested delivery vehicle. Indeed, tolerance of this bacterium is enhanced when it is consumed within a fermented dairy product, compared to a dried probiotic preparation. We investigated both stress tolerance and protein neosynthesis upon growth in i) chemically defined or ii) aqueous phase of Emmental cheeses. Although the same final population level was reached in both media, a slower growth and an enhanced survival of CIRM BIA 1 strain of P. freudenreichii subsp. shermanii was observed in Emmental juice, compared to chemically defined medium. This was accompanied by differences in substrates used and products released as well as overexpression of various early stress adaptation proteins in Emmental juice, compared to chemically defined medium, implied in protein folding, in aspartate catabolism, in biosynthesis of valine, leucine and isoleucine, in pyruvate metabolism in citrate cycle, in the propionate metabolism, as well as in oxidoreductases. All these changes led to a higher digestive stress tolerance after growth in Emmental juice. Mechanisms of stress adaptation were induced in this environment, in accordance with enhanced survival. This opens perspectives for the use of hard and semi-hard cheeses as delivery vehicle for probiotics with enhanced efficacy.

This review deals with beneficial bacteria, with a focus on lactobacilli, propionibacteria, and bifidobacteria. As being recognized as beneficial bacteria, they are consumed as probiotics in various food products. Some may also be used as starters in food fermentation. In either case, these bacteria may be exposed to various environmental stresses during industrial production steps, including drying and storage, and during the digestion process. In accordance with their adaptation to harsh environmental conditions, they possess adaptation mechanisms, which can be induced by pretreatments. Adaptive mechanisms include accumulation of compatible solutes and of energy storage compounds, which can be largely modulated by the culture conditions. They also include the regulation of energy production pathways, as well as the modulation of the cell envelop, i.e., membrane, cell wall, surface layers, and exopolysaccharides. They finally lead to the overexpression of molecular chaperones and of stress-responsive proteases. Triggering these adaptive mechanisms can improve the resistance of beneficial bacteria toward technological and digestive stresses. This opens new perspectives for the improvement of industrial processes efficiency with regard to the survival of beneficial bacteria. However, this bibliographical survey evidenced that adaptive responses are strain-dependent, so that growth and adaptation should be optimized case-by-case. [ABSTRACT FROM AUTHOR]

The impact of Functional foods on the gut microbiota is a fundamental question since shifts in bacterial composition are associated with inflammation progression. Therefore, this study investigated the effects of two types of cheeses fermented by probiotic bacteria in C57BL6 mice either in healthy conditions or in dextran sulfate sodium (DSS)-induced colitis. One cheese was fermented by Propionibacterium freudenreichii CIRM-BIA129. A second kind of cheese was made in industrial conditions to reproduce Emmental but using the above-mentioned strain in combination with Lactobacillus delbrueckii CNRZ327 and Streptococcus thermophilus LMD-9 as starters. The gut microbiota was investigated by shotgun metagenomic sequencing and the taxonomic and functional profiles were assessed through sequence alignment to NCBI taxonomy and KEGG pathways databases. Our results suggest that both treatments did not disturb the microbial community ecology. Emmental intake increased symbionts as Romboutsia and Akkermansia muciniphila. Furthermore, metabolic pathway analysis suggests that A. muciniphila may produce bioactive metabolites as acetate and cooperate with other commensal species to produce indole and gamma-aminobutyric acid. Mice with colitis have restored some of the impaired microbiome metabolic functions when treated with cheese fermented only by Propionibacterium , while the Emmental cheese promoted the increase of Ligilactobacillus murinus. This taxon presented several genes with immunomodulatory activity potential. This study provides insights for engineering functional cheeses to increase beneficial bacteria in the gut. However, further studies are required to investigate their role in regulating the gut-brain axis. Moreover, possible anti-inflammatory mechanisms based on the promotion of Lg. murinus interaction with the host was suggested. • Functional Emmental cheese leads to the expansion of Romboutsia and Akkermansia in the gut of healthy mice • Acetate and GABA metabolism genes from gut microbiota are increased in healthy mice feeding on Emmental. • Microbiota of mice with colitis increases in Ligilactobacillus sp. when treated with Emmental. • Autochthonous Lg. murinus proteins interact in silico with mice Inflammasome. [ABSTRACT FROM AUTHOR]

Propionibacterium freudenreichii is a beneficial Gram-positive bacterium, traditionally used as a cheese-ripening starter, and currently considered as an emerging probiotic. As an example, the P. freudenreichii CIRM-BIA 129 strain recently revealed promising immunomodulatory properties. Its consumption accordingly exerts healing effects in different animal models of colitis, suggesting a potent role in the context of inflammatory bowel diseases. This anti-inflammatory effect depends on surface layer proteins (SLPs). SLPs may be involved in key functions in probiotics, such as persistence within the gut, adhesion to host cells and mucus, or immunomodulation. Several SLPs coexist in P. freudenreichii CIRM-BIA 129 and mediate immunomodulation and adhesion. A mutant P. freudenreichii CIRM-BIA 129Δ slpB (CB129Δ slpB) strain was shown to exhibit decreased adhesion to intestinal epithelial cells. In the present study, we thoroughly analyzed the impact of this mutation on cellular properties. Firstly, we investigated alterations of surface properties in CB129Δ slpB. Surface extractable proteins, surface charges (ζ-potential) and surface hydrophobicity were affected by the mutation. Whole-cell proteomics, using high definition mass spectrometry, identified 1,288 quantifiable proteins in the wild-type strain, i.e., 53% of the theoretical proteome predicted according to P. freudenreichii CIRM-BIA 129 genome sequence. In the mutant strain, we detected 1,252 proteins, including 1,227 proteins in common with the wild-type strain. Comparative quantitative analysis revealed 97 proteins with significant differences between wild-type and mutant strains. These proteins are involved in various cellular process like signaling, metabolism, and DNA repair and replication. Finally, in silico analysis predicted that slpB gene is not part of an operon, thus not affecting the downstream genes after gene knockout. This study, in accordance with the various roles attributed in the literature to SLPs, revealed a pleiotropic effect of a single slpB mutation, in the probiotic P. freudenreichii. This suggests that SlpB may be at a central node of cellular processes and confirms that both nature and amount of SLPs, which are highly variable within the P. freudenreichii species, determine the probiotic abilities of strains. [ABSTRACT FROM AUTHOR]

Dairy propionibacteria are used as cheese ripening starters, as biopreservative and as beneficial additives, in the food industry. The main species, Propionibacterium freudenreichii, is known as GRAS (Generally Recognized As Safe, USA, FDA). In addition to another dairy species, Propionibacterium acidipropionici, they are included in QPS (Qualified Presumption of Safety) list. Additional to their well-known technological application, dairy propionibacteria increasingly attract attention for their promising probiotic properties. The purpose of this review is to summarize the probiotic characteristics of dairy propionibacteria reported by the updated literature. Indeed, they meet the selection criteria for probiotic bacteria, such as the ability to endure digestive stressing conditions and to adhere to intestinal epithelial cells. This is a prerequisite to bacterial persistence within the gut. The reported beneficial effects are ranked according to property's type: microbiota modulation, immunomodulation, and cancer modulation. The proposed molecular mechanisms are discussed. Dairy propionibacteria are described as producers of nutraceuticals and beneficial metabolites that are responsible for their versatile probiotic attributes include short chain fatty acids (SCFAs), conjugated fatty acids, surface proteins, and 1,4-dihydroxy-2-naphtoic acid (DHNA). These metabolites possess beneficial properties and their production depends on the strain and on the growth medium. The choice of the fermented food matrix may thus determine the probiotic properties of the ingested product. This review approaches dairy propionibacteria, with an interest in both technological abilities and probiotic attributes. [ABSTRACT FROM AUTHOR]

Propionibacterium freudenreichii is used as a cheese-ripening starter and as a probiotic. Its reported physiological effects at the gut level, including modulation of bifidobacteria, colon epithelial cell proliferation and apoptosis, and intestinal inflammation, rely on active metabolism in situ. Survival and activity are thus key factors determining its efficacy, creating stress adaptation and tolerance bottlenecks for probiotic applications. Growth media and growth conditions determine tolerance acquisition. We investigated the possibility of using sweet whey, a dairy by-product, to sustain P. freudenreichii growth. It was used at different concentrations (dry matter) as a culture medium. Using hyperconcentrated sweet whey led to enhanced multistress tolerance acquisition, overexpression of key stress proteins, and accumulation of intracellular storage molecules and compatible solutes, as well as enhanced survival upon spray drying. A simplified process from growth to spray drying of propionibacteria was developed using sweet whey as a 2-in-1 medium to both culture P. freudenreichii and protect it from heat and osmotic injury without harvesting and washing steps. As spray drying is far cheaper and more energy efficient than freeze-drying, this work opens new perspectives for the sustainable development of new starter and probiotic preparations with enhanced robustness. [ABSTRACT FROM AUTHOR]

Backgrounds and Aims. Inflammatory Bowel Diseases (IBD), including Ulcerative Colitis (UC), coincide with alterations in the gut microbiota. Consumption of immunomodulatory strains of probiotic bacteria may induce or prolong remission in UC patients. Fermented foods, including cheeses, constitute major vectors for bacteria consumption. New evidences revealed anti-inflammatory effects in selected strains of Propionibacterium freudenreichii. We thus hypothesized that consumption of a functional cheese, fermented by such a strain, may exert a positive effect on IBD. Methods. We investigated the impact of cheese fermented by P. freudenreichii on gut inflammation. We developed an experimental single-strain cheese solely fermented by a selected immunomodulatory strain of P. freudenreichii, CIRM-BIA 129. We moreover produced, in industrial conditions, an Emmental cheese using the same strain, in combination with Lactobacillus delbrueckii CNRZ327 and Streptococcus thermophilus LMD-9, as starters. Consumption of both cheeses was investigated with respect to prevention of Dextran Sodium Sulphate (DSS)-induced colitis in mice. Results. Consumption of the single-strain experimental cheese, or of the industrial Emmental, both fermented by P. freudenreichii CIRM-BIA 129, reduced severity of subsequent DSS-induced colitis, weight loss, disease activity index and histological score. Both treatments, in a preventive way, reduced small bowel Immunoglobulin A (IgA) secretion, restored occludin gene expression and prevented induction of Tumor Necrosis Factor α (TNFα), Interferon γ (IFNγ) and Interleukin-17 (IL-17). Conclusions. A combination of immunomodulatory strains of starter bacteria can be used to manufacture an anti-inflammatory cheese, as revealed in an animal model of colitis. This opens new perspectives for personalised nutrition in the context of IBD. [ABSTRACT FROM AUTHOR]

Spray-drying is expected to be a cost-efficient way to produce probiotic powders. Indeed, a novel simplified process was recently reported, using concentrated sweet whey (30 wt %) as a sole medium for both growth and spray drying of probiotics. The feasibility of scaling up this process was validated in the present work with a semi industrial pilot scale spray dryer. A multi-stage mild-conditions drying process, coupling spray-drying with belt drying and fluid-bed drying, was also applied in this work, in which the final probiotic survival was improved to approximately 100% (>10 9 CFU g −1 ). The change of probiotic viability in the powders was monitored during a 6-month storage, which indicated that storage temperature and moisture content of powders play crucial roles in the stability of probiotic powders. Moreover, spray-drying afforded a strain-dependent enhancement of bacterial tolerance in simulated intestinal fluid, in comparison with fresh cultures. [ABSTRACT FROM AUTHOR]