Yeast Yeast 2011; 28: 547–554. Published online 30 May 2011 in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/yea.1858 Research Article Ethanol production by a new pentose-fermenting yeast strain, Scheffersomyces stipitis UFMG-IMH 43.2, isolated from the Brazilian forest Adriana D. Ferreira 1 , Solange I. Mussatto 2 *, Raquel M. Cadete 3 , Carlos A. Rosa 3 and Silvio S. Silva 1 1 Department of Biotechnology, Engineering College of Lorena, University of S˜ ao Paulo, Lorena, SP, Brazil 2 Institute for Biotechnology and Bioengineering (IBB), Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal 3 Department of Microbiology, Institute of Biological Science, Federal University of Belo Horizonte, MG, Brazil *Correspondence to: Solange I. Mussatto, Institute for Biotechnology and Bioengineering (IBB), Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal. E-mail: solange@deb.uminho.pt; solangemussatto@hotmail.com Received: 18 February 2011 Accepted: 20 April 2011 Abstract The ability of a recently isolated Scheffersomyces stipitis strain (UFMG-IMH 43.2) to produce ethanol from xylose was evaluated. For the assays, a hemicellulosic hydrolysate produced by dilute acid hydrolysis of sugarcane bagasse was used as the fermentation medium. Initially, the necessity of adding nutrients (MgSO 4 ·7H 2 O, yeast extract and/or urea) to this medium was verified, and the yeast extract supplementation favoured ethanol production by the yeast. Then, in a second stage, assays under different initial xylose and cell concentrations, supplemented or not with yeast extract, were performed. All these three variables showed significant (p < 0.05) influence on ethanol production. The best results (ethanol yield and productivity of 0.19 g/g and 0.13 g/l/h, respectively) were obtained using the hydrolysate containing an initial xylose concentration of 30 g/l, supplemented with 5.0 g/l yeast extract and inoculated with an initial cell concentration of 2.0 g/l. S. stipitis UFMG-IMH 43.2 was demonstrated to be a yeast strain with potential for use in xylose conversion to ethanol. The establishment of the best fermentation conditions was also proved to be of great importance to increasing the product formation by this yeast strain. These findings open up new perspectives for the establishment of a feasible technology for ethanol production from hemicellulosic hydrolysates. Copyright  2011 John Wiley & Sons, Ltd. Keywords: Scheffersomyces stipitis ; fermentation; ethanol; sugarcane bagasse; hemicellulosic hydrolysate Introduction In the last decade, ethanol has experienced unseen levels of attention, due to its value as a fuel alternative to gasoline, the increase of oil prices and climatic changes, besides being a renew- able and sustainable energy source, efficient and safe to the environment. Currently, worldwide ethanol production is at high levels and corn is the main raw material used for this purpose, but this scenario must change due to techno- logical improvements that are being developed for the production of low-cost lignocellulosic ethanol (Mussatto et al., 2010). Among the vari- ety of lignocellulosic materials, including agri- cultural and agro-industrial residues that can be used for this purpose, sugarcane bagasse (the solid residue obtained after sugar cane juice extrac- tion) has attracted great interest, since it has a composition rich in polysaccharides convertible to fermentable sugars, which correspond to about 72.5% of the material composition (Rocha et al., 2011). Copyright  2011 John Wiley & Sons, Ltd.