Selection of Saccharomyces cerevisiae isolates for ethanol production in the presence of inhibitors
Eight yeast isolates identified as Saccharomyces cerevisiae were recovered from molasses-using Cuban distilleries and discriminated by nucleotide sequence analysis of ITS locus. The isolates L/25-7-81 and L/25-7-86 showed the highest ethanol yield from sugarcane juice, while L/25-7-12 and L/25-7-79 showed high ethanol yield from sugarcane molasses. The isolate L/25-7-86 also displayed high fermentation capacity when molasses was diluted with vinasse. In addition, stress tolerance was evaluated on the basis of growth in the presence of inhibitors (acetic acid, lactic acid, 5-hydroxymethylfurfural and sulfuric acid) and the results indicated that L/25-7-77 and L/25-7-79 congregated the highest score for cross-tolerance and fermentation capacity. Hence, these isolates, especially L/25-7-77, could serve as potential biological platform for the arduous task of fermenting complex substrates that contain inhibitors. The use of these yeasts was discussed in the context of second-generation ethanol and the environmental and economic implications of the use of vinasse, saving the use of water for substrate dilution.
KeywordsFermentation capacity 5-HMF Stress resistance Vinasse Yeast selection Weak organic acid
K. T. was supported by the United Nations University (UNU-BIOLAC Biotechnology for Latin America and The Caribbean) and by the Pérez-Guerrero Trust Fund for South–South Cooperation of UNDP in the frameworks of projects INT/13/K08 and INT/16/K10. This work was partially sponsored by UNU-BIOLAC program and by the Bioethanol Research Network of the State of Pernambuco (CNPq-FACEPE/PRONEM APQ-1452-2.01/10).
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Conflict of interest
The author declares no conflict of interest.
This article does not contain any studies with human participants or animals performed by the author.
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