Conversion of fermentable sugars from hydrolysates of soybean and oat hulls into ethanol and xylitol by Spathaspora hagerdaliae UFMG-CM-Y303

•Newly isolated xylose-fermenting strain of Spathaspora hagerdaliae UFMG-CM-Y303 was cultured.•Soybean and oat hulls were acid and enzymatically hydrolyzed.•Hydrolysates were high in glucose and xylose concentration, and high osmotic pressures.•Both ethanol and xylitol were produced.•Cultivations were studied in bioreactors, testing anaerobiosis and aerobiosis. We evaluated the ability of a recently isolated xylose-fermenting strain of Spathaspora hagerdaliae UFMG-CM-Y303 to convert acid AH and enzymatic EH hydrolysates of soybean and oat hulls, or their mixture AEH, into second-generation ethanol and xylitol. All hydrolysates presented high concentrations of glucose and xylose, showing high osmotic pressures >1300 mOsm•kg−1). Bioreactor cultures under different combinations of aeration and agitation (anaerobiosis, 180 rpm; 0.5 vvm or 1 vvm of air, 300 rpm) were performed. The AH fermentation produced yields of ethanol varying from 0.28 g•g−1 to 0.36 g•g−1 and yields of xylitol varying from 0.11 g•g−1 to 0.31 g•g−1. The fermentation of EH and AEH under anaerobiosis showed low cell viability, probably caused by the very high osmotic pressure of these hydrolysates. However, under aerobic conditions cell growth was normal and yields of ethanol varied between 0.23 g•g−1 and 0.40 g•g−1, whereas yields of xylitol varied from 0.17 g•g−1 to 0.25 g•g−1. These results suggest that Sp. hagerdaliae UFMG-CM-Y303 has the potential for biotechnological applications in biorefinery processes for the production of alcohols.