| Abstract |
Bioethanol is the alternative biofuel, which is produced by the fermentation of agricultural by-products such as sugarcane, corn and cassava. The ambient temperature causes a trouble in ethanol production due to the heat which kills the yeasts during fermentation. Thus, the screening of a thermotolerant yeast is undertaken to search for the most effective yeast strain for efficient ethanol fermentation. The screening and molecular identification of thermotolerant yeasts were established in our laboratory based on many literatures with slight modification. Samples were collected from different parts of Thailand. Five promising strains, CP1GG6 (isolated from green grape in Kang Khro district, Chaiyaphum), KK5SO1 (isolated from soil in Ubolratana district, Khon Kaen), KK1SO1 (isolated from soil in Phon district, Khon Kaen), KK4RG (isolated from red grape in Muang district, Khon Kaen) and SR1SO7 (isolated from soil in Kaeng Khoi district, Saraburi) were able to grow at 39, 41, 43, 45 and 45°C, respectively. The morphological and physiological characteristics showed that yeast colonies were cream-white in color, convex profile, smooth and opaque with glossy surface. The molecular identification based on the D1/D2 domain of large subunit (26S) rDNA gene showed that KK1SO1 and KK5SO1, SR1SO7, CP1GG6 and KK4RG2 were identified as Candida tropicalis, Candida nivariensis, Pichia kudriavzevii and Hanseniaspora opuntiae, respectively. The identified yeasts, especially, C. tropicalis, P. kudriavzevii and H. opuntiae have been reported to be potential candidates for ethanol production so they will be beneficial for efficient ethanol production in the future. |
Publication
Journal Publication
ไทย