Produção sustentável de etanol 2g a partir do resíduo cultural do abacaxizeiro (Ananas Comosus): otimização do pré-tratamento com peróxido de hidrogênio

Abstract

The growing demand for renewable energy and the need for sustainable management of agro-industrial waste motivate the search for new feedstocks for biofuels. Pineapple (Ana nas comosus) crop residue, an abundant lignocellulosic biomass in the state of Tocantins, has significant underutilized potential for second-generation (2G) ethanol production. This study aimed to optimize the chemical pretreatment of this residue with hydrogen peroxide (H₂O₂) under different pH and concentration conditions, evaluating its impact on delignifi cation, enzymatic hydrolysis yield, and subsequent ethanol production. The biomass was chemically characterized in natura and after pretreatments (1% H₂O₂ pH 4.5; 1% H₂O₂ pH 11.5; and 3% H₂O₂ pH 11.5). The optimal condition was subjected to enzymatic hydrolysis, followed by fermentation with Saccharomyces cerevisiae. Fermentation kinetics were mon itored by CO₂ production and fitted to a non-linear regression model to estimate ethanol production. The pretreatment with 1% H₂O₂ at pH 11.5 proved to be the most effective, reducing the lignin content by 74% (from 25.55% to 6.57%) and increasing the accessible cellulose fraction from 13.05% to 47.74%. The enzymatic hydrolysis coefficient reached an average of 17.3%. Kinetic modeling revealed a maximum estimated ethanol production of 153.74 L.t⁻¹. The results confirm the technical feasibility of using pineapple residue for 2G ethanol production, highlighting the effectiveness of the alkaline oxidative pretreatment and positioning this biomass as a promising alternative for the valorization of agricultural by products.