engleski

Selection of non-Saccharomyces yeast with tolerance to high lactic acid concentrations for production of biochemicals

Non-Saccharomyces yeasts can grow on carbohydrates that are constituents of lignocellulosic biomass and can have resistance to the different 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 from waste lignocellulosic feedstocks. In this work, selection of non-Saccharomyces yeasts from genera Scheffersomyces, Kluyveromyces, Spathaspora and Candida, as well as yeasts Pachysolen tannophilus JCM 31685 and Schwaniomyces polymorphus ZIM 2980 for their tolerance/resistance to high concentrations of lactic acid was performed. Based on the experiments performed, the yeast with the highest resistance to elevated lactic acid concentrations 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, Yethanol/S = 0, 46 g g-1, Prethanol/S = 0, 19 g L-1 h-1 ; YPD + lactic acid, μmax = 0, 10 h-1, Yethanol/S = 0, 42 g g-1, Prethanol/S = 0, 03 g L-1 h-1). Ability of K. marxianus NBRC 1777 to grow in conditions with high lactic acid concentration gives this yeast a potential as a microorganism suitable for genetic transformations to yeast strain for lactic acid production from waste lignocellulose. Acknowledgements The research was financially supported by Croatian Science Foundation under the project No. IP-2018-01-9717.

non-Saccharomyces yeast, ethanol

nije evidentirano