Probiotic Lactic Yeast ® Kluyveromyces B0399: immune system stimulation, gut colonization, bifidobogenic effect and other strain specific, probiotic properties

a Department of Pharmaceutical Sciences, University of Bologna, Bologna, Italy

b Department of Food and Nutritional Sciences, University of Reading, RG6 6AP, Reading, UK

c COOP Italia, Casalecchio di Reno, Bologna, Italy

* Correspondence to Adele Costabile, Food Microbial Science Unit, Department of Food and

Nutritional Sciences - University of Reading, RG6 6AP, Reading, UK, telephone +44 (0)118 378

6218, fax +44 (0)118 931 0080, (a.costabile@reading.ac.uk)

Running title: Probiotic potential of K. marxianus fragilis B0399 (Turval Laboratories Italy)

Porpose:

Considering the increase in the consumption of yeasts as human probiotics, the aim of this study was to broadly investigate the beneficial properties of the lactic yeast K. marxianus fragilis B0399.

Several potential probiotic traits of Kluyveromyces marxianus fragilis B0399 were investigated using in vitro assays, including adhesion and immune modulation.

Methods:

The researchers analyzed the effect of the administration of 10^7 CFU/day of Kluyveromyces marxianus fragilis B0399 on composition and metabolic activity of the human intestinal microbiota.

The study was carried out in a 3-stage continuous system, consisting of culture media, simulating the human colon..

Results:

They demonstrated that this strain was highly adhesive to the human enterocyte-like Caco-2 cells, these cells are used in vitro models to simulate the intestinal epithelium (enterocytes).

So the fact that the Kluyveromyces marxianus fragilis B0399 is able to adhere to Caco-2 shows us that it is capable of colonizing the human gut.

Researchers demonstrated also , that it is able to modulate the immune response by acting on cytokines (pro and anti / inflammatory). These molecules are part of the system by which cells communicate. The pro-inflammatory cytokines are produced by cells subject to an inflammatory stimulus, while the anti-inflammatory cytokines from healthy cells.

The normal situation of a healthy individual is given by the balance of the two. In a sick person we will have locally majority of pro-inflammatory cytokines. Precisely in the latter case, the Kluyveromyces marxianus fragilis B0399 acts by inducing a reduction in the production of pro-inflammatory cytokines. This ability has been demonstrated in vitro model inducing a inflammatory stimulus (LPS) to the cells representing the intestinal tissue cells (PBMCs and Caco-2).

Furthermore, Kluyveromyces marxianus fragilis B0399 impacted on the colonic microbiota, increasing the Bifidobacterial concentration in the stages of the colonic model system simulating the proximal and transverse colon.

Short chain fatty acids acetate and propionate also increased following the yeast supplementation. These substances provide energy and promote the growth of epithelial cells of the colon.

Finally it has been shown that the Kluyveromyces marxianus fragilis B0399 induces the reduction of the toxicity of the fecal liquid.

Summary:

The effects of K. marxianus fragilis B0399 on adhesion, immune function and colonic microbiota demonstrate that this strain possesses a number of beneficial and strain-specific properties desirable in a microorganism considered for application as a probiotics.

The results for points

This study shows that the Kluyveromyces B0399 in the dosage of 10 million CFU / day:

• It colonizes the intestine: it is extremely adhesive to human enterocytes of the intestinal epithelium;

• it regulates the immune response by acting on cytokines (pro-and anti-inflammatory): in particular in inflammatory state produces a reduction in the production of pro-inflammatory cytokines

• it affects the microbial flora of the colon, stimulating the increase of the concentration of bifidobacteria;

• it provides energy and promotes the growth of epithelial cells of the colon by stimulating the production of short-chain fatty acetate and propionate;

• It reduces the toxicity of liquid faecal

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Potential probiotic Kluyveromyces marxianus fragilis B0399 modulates the immune response in Caco-2 cells and PBMCs and impacts on the human gut microbiota in an in vitro colonic model system