Isolation, identification and evaluation of yeasts with probiotic potential in vitro from Paipa cheese whey

The objective of this study was to isolate and identify yeast strains from whey of Paipa cheese, and evaluate in vitro their potential as probiotics potential in animal feed. The yeast strains were isolated using chloramphenicol-glucose-medium, purified on PDA agar and molecularly characterized. A total of 10 yeast strains were isolated from the whey of Paipa cheese, including Candida kefyr, Kluyveromyces marxianus, Pichia fermentans, among others. These strains were further screened for their use as alternative yeast probiotics strains for animal feed. Resistance to bile salts (0.05, 0.1, 0.15, 0.20, 0.25 and 0.30 %), stability at stomach pH (1.5, 2.0, 2.5, 3.0, 3.5 and 4.0) and resistance to gastric juice (pH 1.5, NaCl 0.2 % and pepsin 0.32 %) were evaluated. The isolates of Kluyveromyces marxianus (30_4) y la Pichia fermentans (28_5) had a higher growth at 0,3 % bile salts. In the pH test, the best performance was for P. marxianus and Yarrowia lipolytica. Finally, in the gastric juice test, Candida kefyr and K. marxianus (R_1) strains were the best. K. marxianus (30_4) and P. fermentans (28_5) strains presented good performance in almost all tests, for that reason, these yeasts isolated from Paipa cheese whey have potential for application as probiotics in animal feed.