along time,yeast shave been used forthe production of variousbiocompounds.Newstrainsmay exhibitavarietyofbenefits andapplicationstomodernandclassicbiotechnologicalprocessing. Pichia kluyveri and Pseudozyma tsukubaensis wereisolatedfrompeach(Prunus persica) andnectarine(P.persica var. nucipersica) fruit,respectively,andidentified throughamolecularapproach(D1/D228SrDNA)and phylogeneticanalysis.Theisolatedyeastsweretestedbasedontheirabilitytoproducegalactooligo- saccharides fromlactoseusinglivingwholecells.Forbothselectedstrains,aninvitroanalysisof probioticpropertieswascarriedout.Amaximumyieldof14.01%and15.71%(w/w)galactooligosacchar- ides wasobtainedfromalactosesolutionreaction(40%w/v)using P.kluyveri and P.tsukubaensis, respectively,at30 1C, pH7.0and24h.Tothebestofourknowledge,thisisthe first studyreportingthe potentialof P.kluyveri and P.tsukubaensis to producegalactooligosaccharidesfromlactose.Itwasshown that the P.kluyveri strain hasdesirableprobioticpotentialusingthefollowingparameters:thermo- tolerance,antibacterialactivityagainstsomepathogenicbacterialspeciesandtolerancetoacidand bile