Aeration-enhanced bioethanol production

• Bioethanol production by E. coli KO11 was studied under microaerated conditions.
• Oxygen feeding for the first 8 h at 5 mmol/L/h maximized the ethanol concentration.
• The sugar consumption rate was promoted under aerated fermentation.
• Higher specific growth rate was obtained at aerated conditions.
• 14.44% higher ethanol production was achieved using aeration.

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.

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