Producción de bioetanol a partir de lodos papeleros mediante el uso de celulasa de origen fúngico

Abstract

CONDITION FOR PUBLICATION OF PROJECT. This study addresses the valorization of paper sludge as a raw material for bioethanol production, with the aim of evaluating its energy potential and proposing a sustainable alternative to conventional waste disposal. The research is justified by the need to reduce the environmental impact of the paper industry and to take advantage of lignocellulosic byproducts with high organic content. The study was carried out through the physical-chemical characterization of liquid and wet sludge, considering initial parameters such as moisture, total solids, pH, and carbohydrate content. Subsequently, chemical pretreatments, enzymatic hydrolysis to release reducing sugars, and alcoholic fermentation were carried out under a central composite design with two operating variables: temperature (23–37 °C) and incubation time (14–82 h). Density, FTIR spectroscopy, and refractive index techniques were used to verify the product. The results showed that wet sludge, with a higher solids fraction (24.19%), reached a maximum concentration of 74.29 g/L of ethanol, surpassing liquid sludge (65.57 g/L with 1.44% solids). This difference was explained by the greater availability of carbohydrates (3.85 g/L versus 3.32 g/L) and the higher conversion efficiency observed in wet sludge. Likewise, FTIR analysis confirmed the presence of ethanol along with secondary by-products (acetic acid and acetaldehyde), which affected the purity of the distillate. The preliminary economic evaluation indicated that the unit cost of production under laboratory conditions was high (USD 3676/L) due to the low volume of bioethanol obtained; however, the larger-scale projection reduced this value to USD 11.36/L, demonstrating the potential of the process under optimization and scaling conditions. Keywords: industrial waste, alcoholic fermentation, bioenergy, sustainability.