Exploring the Biodiversity of Red Yeasts for In Vitro and In Vivo Phenotypes Relevant to Agri-Food-Related Processes

Red yeasts grow on food wastes, show antagonistic activity against food-spoilage microorganisms,
produce food supplements, and may be utilized as feed-supplements themselves to
positively modulate the quali-quantitative composition of intestinal microbiota. Therefore, they show
a variety of possible biotechnological applications in agri-food-related processes. Here, to further
explore the biotechnological potential of red yeasts, eleven strains ascribed to different species of
the genera Rhodotorula and Sporobolomyces, differing for biomass and carotenoids production, were
characterized in vitro for biofilm formation, invasive growth, and growth at the temperature range of
20–40 C and in vivo for their antagonistic activity against the fungal pathogen and patulin producer
Penicillium expansum. Most of them formed cellular MAT and showed invasive growth as well as
adhesion to plastic materials. Four strains determined a significant reduction of fruit decay caused by
P. expansum on apple fruit while the remaining seven showed different degrees of biocontrol activity.
Finally, none of them grew at body temperature (>37 C). Statistical analyses of both qualitative
and quantitative phenotypic data, including biomass and carotenoids production, gathered further
information on the most interesting strains for the biotechnological exploitation of red yeasts in
agri-food-related process.