Studies on selection of xylose utilizing yeast for ethanol fermentation were used the waste of agriculture in total 56 samples. In the experiments were conducted by an enrichment technique in YPX broth at 37°C. A total of 60 yeast strains were obtained. Of these, 35 yeast strains were selected for growing on YPD, YPS, YPX and YNB plates agar at 37°C, 40°C, 42°C and 45°C, also cell morphology, characteristics at 37 °C and identification of selected strains were studied. The results showed, only 8 strains were grown well on YPD medium at any temperatures, 6 strains on YPS and 2 strains on YPX and YNB plates agar. Under the microscope, the cell shape of yeasts exhibited elongate, round and budding. All of the selected strains contained catalase positive. Ethanol fermentation from xylose 2% only OX17, OX22 and OX30 showed slightly higher than the others and Kluyveromyces marxianus BUNL-21. In addition, OX17 was strong resistant on chemical toxic reagent and OX25 was growth fast and different chararistic from the others strains. Yeast identification were carried out by nucleotide sequencing of the D1/D2 domain of the large subunit rRNA gene, revealing that the isolated strains can be categorized into Blastobotrys adeninivorans 3 strains and Candida tropicalis 2 strains.
Keyword: yeast, temperatures, lignocellulose, xylose, ethanol