In recent years, growing attention has been devoted to maximize the product yield for the conversion of biomass into ethanol. In this study, microaerated conditions were established to enhance the ethanol yield by Eschericia coli KO11. According to the results, limited aeration was found to be an important factor to increase the ethanol yield by improving the consumption of sugars and the production of biomass. The best result was obtained using oxygen transfer rate (OTR) of 5 mmol/L/h, reaching 19.66 g/L of ethanol at 48 h using quince pomace as substrate. The assays showed that less than 5% of the initial sugar remained at the end of the fermentation, achieving a biomass concentration of 7.3 g/L. In conclusion, we successfully carried out lab-scale production of bioethanol from quince pomace using the ethanologenic E. coli KO11. In particular, microaerobic ethanol fermentation at OTR = 5 mmol/L/h is suggested for the efficient utilization of sugars in quince pomace. Considering the abundance of raw material and the ease of large-scale production, this improvement will have a considerable impact on the total cost of bioethanol. (C) 2014 Elsevier B.V. All rights reserved.