Sustainable bioethanol from cardboard: an environmentally conscious solution for the second-generation biofuel industry

The production of second-generation bioethanol from lignocellulosic waste is a sustainable alternative for diversifying the energy matrix and utilizing solid waste. This work evaluated the potential of cardboard as a raw material for the production of second-generation bioethanol, comparing the efficiency of two pretreatments in enzymatic hydrolysis and alcoholic fermentation. Pretreatments by immersion in water at room temperature and by boiling were evaluated, followed by enzymatic hydrolysis, alcoholic fermentation, and quantification of ethanol by high-performance liquid chromatography (HPLC). The pretreatment in water at room temperature provided greater availability of fermentable sugars and higher bioethanol production. The strong correlation between the hydrolysis coefficient and the estimated bioethanol (r = 0.9878) confirmed the importance of hydrolysis, while the moderate correlation with the bioethanol obtained after fermentation (r = 0.5347) indicated the influence of fermentative factors on the final yield. It is concluded that cardboard is a viable raw material for the production of second-generation bioethanol, contributing to the utilization of lignocellulosic waste and the diversification of biofuel production in Brazil.