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Production of bioethanol in sugarcane bagasse hemicellulosic hydrolysate by Scheffersomyces parashehatae, Scheffersomyces illinoinensis and Spathaspora arborariae isolated from Brazilian ecosystems

Cadete, R.M., Melo‐Cheab, M.A., Dussán, K.J., Rodrigues, R.C.L.B., da Silva, S.S., Gomes, F.C.O., Rosa, C.A.
Journal of applied microbiology 2017 v.123 no.5 pp. 1203-1213
Scheffersomyces, Wickerhamomyces, bioethanol, boring insects, ecosystems, ethanol, ethanol production, fermentation, hydrolysates, sugarcane bagasse, xylitol, yeasts
AIMS: This study aimed to evaluate new d‐xylose‐fermenting yeasts from Brazilian ecosystems for the production of second‐generation ethanol. METHODS AND RESULTS: d‐xylose‐fermenting yeasts isolated from rotting wood and wood‐boring insects were identified as the species Scheffersomyces parashehatae, Scheffersomyces illinoinensis, Spathaspora arborariae and Wickerhamomyces rabaulensis. Among the yeasts tested, those of Sc. parashehatae exhibited the highest ethanol production when cultivated on complex medium (Yₚ/ₛ ᵉᵗ = 0·437 g g⁻¹). Sheffersomyces illinoinensis and Sp. arborariae showed similar ethanol production in this assay (Yₚ/ₛ ᵉᵗ up to 0·295 g g⁻¹). In contrast, in sugarcane bagasse hemicellulosic hydrolysate, Sc. parashehatae and Sc. illinoinensis exhibited similar ethanol production (Yₚ/ₛ ᵉᵗ up to 0·254 g g⁻¹), whereas Sp. arborariae showed the lowest results (peak Yₚ/ₛ ᵉᵗ = 0·160 g g⁻¹). Wickerhamomyces rabaulensis exhibited a remarkable xylitol production (Yₚ/ₛ ˣʸˡ = 0·681 g g⁻¹), but producing low levels of ethanol (Yₚ/ₛ ᵉᵗ = 0·042 g g⁻¹). CONCLUSIONS: The novel d‐xylose‐fermenting yeasts showed promising metabolic characteristics for use in fermentation processes for second‐generation ethanol production, highlighting the importance of bioprospecting research of micro‐organisms for biotechnological applications. SIGNIFICANCE AND IMPACT OF THE STUDY: This study widens the scope for future researches that may examine the native yeasts presented, as limited studies have investigated these species previously.