Production of prebiotic galactooligosaccharides from lactose by Pseudozyma tsukubaensis and Pichia kluyveri

For a long time, yeasts have been used for the production of various biocompounds. New strains may exhibit a variety of benefits and applications to modern and classic biotechnological processing. Pichia kluyveri and Pseudozyma tsukubaensis were isolated from peach (Prunus persica) and nectarine (P. persica var. nucipersica) fruit, respectively, and identified through a molecular approach (D1/D2 28S rDNA) and phylogenetic analysis. The isolated yeasts were tested based on their ability to produce galactooligosaccharides from lactose using living whole cells. For both selected strains, an in vitro analysis of probiotic properties was carried out. A maximum yield of 14.01% and 15.71% (w/w) galactooligosaccharides was obtained from a lactose solution reaction (40% w/v) using P. kluyveri and P. tsukubaensis, respectively, at 30 °C, pH 7.0 and 24 h. To the best of our knowledge, this is the first study reporting the potential of P. kluyveri and P. tsukubaensis to produce galactooligosaccharides from lactose. It was shown that the P. kluyveri strain has desirable probiotic potential using the following parameters: thermotolerance, antibacterial activity against some pathogenic bacterial species and tolerance to acid and bile.