| Abstract | Ne-Saccharomyces kvasci mogu rasti na različitim ugljikohidratima prisutnim u lignoceluloznim sirovinama te mogu imati veću otpornost prema stresnim uvjetima pri kojima se provodi bioproces. Ova svojstva ne-Saccharomyces kvasaca omogućavaju njihovu primjenu u proizvodnji različitih enzima i biokemikalija. U ovom radu provedena je selekcija ne-Saccharomyces kvasaca iz rodova Scheffersomyces (Scheffersomyces stipitis JCM 10742, Scheffersomyces lignosum JCM 9837, Scheffersomyces shehatae JCM 9840) i Kluyveromyces (Kluyveromyces marxianus NBRC 1777, Kluyveromyces marxianus DMKU 3-1042, Kluyveromyces marxianus CBS 712) te kvasaca Pachysolen tannophilus JCM 31685 i Schwaniomyces polymorphus ZIM 2980. Odabir je proveden na temelju mogućnosti rasta na ugljikohidratima prisutnim u lignoceluloznim sirovinama, glavnim produktima metabolizma i otpornosti ovih kvasaca na visoke koncentracije mliječne kiseline. Za uzgoj u većem mjerilu odabran je kvasac koji može tolerirati visoke koncentracije mliječne kiseline i rasti na svim ugljikohidratima prisutnim u lignoceluloznim sirovinama. Uzgoj kvasca Kluyveromyces marxianus NBRC 1777 proveden je u hranjivim YPD podlogama s i bez mliječne kiseline. Dinamika rasta kvasca i proizvodnje etanola u navedenim podlogama okarakterizirana je osnovnim biokinetičkim parametrima (YPD, μmax = 0,40 h-¹, Yetanol/S = 0,46 g g-1, Pretanol/S = 0,19 g L-1 h-1; YPD + mliječna kiselina, μmax = 0,10 h-¹, Yetanol/S = 0,42 g g-¹, Pretanol/S = 0,03 g-¹L h-¹). |
| Abstract (english) | Non-Saccharomyces yeasts can grow on carbohydrates that are constituents of lignocellulosic biomass and have greater resistance to the stress conditions under which the bioprocess is carried out. These properties of non-Saccharomyces yeasts allow their application in the production of various enzymes and biochemicals. In this paper, selection of non-Saccharomyces yeasts from genera Scheffersomyces (Scheffersomyces stipitis JCM 10742, Scheffersomyces lignosum JCM 9837, Scheffersomyces shehatae JCM 9840) and Kluyveromyces (Kluyveromyces marxianus NBRC 1777, Kluyveromyces marxianus DMKU 3-1042, Kluyveromyces marxianus CBS 712), as well as yeasts Pachysolen tannophilus JCM 31685 and Schwaniomyces polymorphus ZIM 2980 was performed. Selection was made based on the growth potential on the carbohydrates present in the lignocellulosic biomass, the main products of metabolism, and the resistance of these yeasts to high concentrations of lactic acid. Based on the experiments performed, the yeast with the highest resistance to elevated lactic acid concentrations and ability of growth on all carbohydrates was selected for cultivation on a larger scale. Cultivation of yeast Kluyveromyces marxianus NBRC 1777 in nutrient YPD media with and without lactic acid was performed in order to determine the dynamics of yeast growth in these conditions. The growth and ethanol production is characterized by basic biokinetic parameters (YPD, μmax = 0,40 h-¹, Yetanol/S = 0,46 g g-¹, Pretanol/S = 0,19 g L-¹h-¹; YPD + lactic acid, μmax = 0,10 h-¹, Yetanol/S = 0,42 g g-¹, Pretanol/S = 0,03 g L-¹ h-¹). |
