Estimativa do potencial de produção de metano a partir de resíduos agroindustriais de manga (Mangifera indica L.) e maracujá (Passiflora edulis Sims) em reatores anaeróbios em batelada

Abstract

The increasing generation of agro-industrial waste and the need for sustainable energy alternatives have driven research focused on the energy recovery of residual biomass. In this context, lignocellulosic residues from fruit processing, such as mango and passion fruit peels, show potential for application in anaerobic digestion due to their high concentration of biodegradable organic matter. However, the presence of lignin can hinder the microbiological degradation of the substrate, making it necessary to apply pretreatments capable of increasing the availability of access to biomass. Thus, this work aimed to estimate the methane production potential in batch anaerobic reactors using mango and passion fruit peels subjected to acid and alkaline pretreatments. Initially, the substrates were crushed, dried, and subjected to chemical treatments using acid and alkaline solutions. Subsequently, the materials were characterized in terms of physicochemical parameters, including pH, Chemical Oxygen Demand (COD), total carbohydrates, and total solids. Next, batch anaerobic reactors were assembled using pre-treated substrates and inoculated with anaerobic biomass. During the process, the COD and carbohydrate removal efficiencies were evaluated, in addition to the theoretical estimate of methane production from the removed COD. The results demonstrated that the efficiency of the pretreatments varied according to the substrate used. For passion fruit, the alkaline pretreatment showed the best results, achieving a COD removal efficiency of 33.83% and an estimated production of 91.53 mL of CH4. For mango, the best performance was observed in the acidic pretreatment, with a COD removal efficiency of 40.68% and an estimated production of 96.35 mL of CH4. These results show that the response to the pretreatments is directly related to the physicochemical and structural characteristics of each biomass. Thus, the application of chemical pretreatments has proven to be a promising strategy to increase the biodegradability of lignocellulosic waste and enhance its energy recovery in anaerobic systems.