Valorización de residuos de pedúnculo de banano para la producción de bioetanol de segunda generación

Abstract

CONDITION FOR PUBLICATION OF PROJECT. This study explores the potential of banana peduncle as a raw material for second-generation bioethanol production and as a source of phenolic compounds. For this, prior to ethanol production, a total of 46.01 mg GAE/g dw of polyphenols was recovered by four-stage ultrasound-assisted extraction, and ethanol production was compared with that of BP samples processed without prior polyphenol extraction. The steam explosion promoted greater solubilization of hemicellulose in the sample with the extraction of polyphenols; however, it effectively altered the structure of the biomass in both cases, preserving the cellulose matrix and improving its accessibility. This allowed an enzymatic hydrolysis yield of 80% (52 g/L glucose), followed by a production of 24 g/L ethanol. No significant differences in fermentation yield were observed between samples with and without prior polyphenol extraction. On the other hand, direct fermentation of the extracted and concentrated BP juice was also carried out, which showed concentration-dependent inhibition. At concentrations of 5X and 10X, Saccharomyces cerevisiae maintained cell populations (~10^6 cells/mL) similar to those of the control medium and produced 23.07 and 35.41 g/L of ethanol, respectively. However, at 10X, the accumulation of phenolic content caused an increase in the lag phase, and at a concentration of 15X, it caused severe inhibition, which limited sugar consumption and prevented ethanol production. Keywords: banana peduncle, ethanol, polyphenols, inhibition, yeast, SAFs.