EVALUATION OF THE IN VITRO PROBIOTIC POTENTIAL OF A Kluyveromyces marxianus STRAIN USED IN ANIMAL NUTRITION

BOTTARO, NICOLÁS; PRIETO FABRE, FEDERICO; SOLDANO, ANABEL; MATTIO, MÓNICA; MORELLI, MATÍAS; ERMILIO, ALEJO; MARCHISIO, MARTÍN; ZACARIAS, SILVIA MERCEDES

Cordoba

Congreso; XIX Congreso de la Sociedad Argentina de Microbiología General; 2024

Sociedad Argentina de Microbiología General

Kluyveromyces marxianus is a rapidly growing thermotolerant yeast well known for itsprobiotic properties, promoting intestinal health and improving digestion in animals and humans.It also stands out for secreting a variety of lytic enzymes and fermenting different sugars,particularly those rich in lactose, such as whey.In Argentina, one of the world’s leading cheese producers, dairy companies generateresidual liquid fraction known as cheese whey, which represents approximately 90% of the milkemployed. Giving away those goods without treatment or valorization has a considerableenvironmental impact and a significant economic loss. K. marxianus can potentially convert thisbyproduct into a high-value input for animal feed, turning waste into a valuable resource forproducing probiotic food for livestock.The probiotic attributes of microorganisms are specie and strain specific. Therefore, thepresent study aimed to explore the functional properties of K. marxianus Up810 in vitro anddetermine its potential use as a probiotic. To assess its effectiveness, we conducted co-aggregation and antagonism assays using spot tests to determine if the yeast could inhibit thegrowth of pathogens such as Escherichia coli and Salmonella Typhimurium. Additionally, weinvestigated its resistance to acidic conditions (pH 2 and pH 3) and its tolerance to bile salts,which are important factors for its survival in the gastrointestinal tract. We also evaluated itsability to form biofilms on polystyrene plates.The results showed that the evaluated K. marxianus strain had significant co-aggregation abilitywith the studied pathogens, demonstrating 63.8 % co-aggregation with E. coli and 50.7 % withS. Typhimurium. However, no antagonism was observed in the spot test against thesepathogens. The strain exhibited remarkable resistance to acidity and bile salts, maintaining itsviability without significant reduction in counts. Additionally, K. marxianus demonstrated aconsistent aptitude to develop biofilms at all assessed time points, reaching its maximum at 48hours of cultivation.K. marxianus’s ability to co-aggregate with E. coli and S. Typhimurium, along with its biofilmformation capacity which could facilitate its adhesion to the intestinal mucosa, highlights theprobiotic potential of this strain. Its resistance to acidic conditions and high concentrations of bilesalts suggests that this yeast could survive the restrictive conditions of the gastrointestinal track,positioning it as a microorganism with a great probiotic potential for developing productsintended for animal feed.