Exploring the potential of red araçá pomace as a feedstock for biogas and biofertilizer production after antioxidant recovery in an organic biorefinery framework

This study investigates the transformative potential of an integrated biorefinery model designed to convert agricultural waste, specifically byproducts from red araçá pomace (Psidium cattleianum), into valuable resources. By employing solid–liquid extraction (SLE) and sequential anaerobic digestion (AD), this approach not only recovers natural antioxidants but also generates biogas and biofertilizers from residual biomass, exemplifying a circular economy in action. Optimized extraction conditions yielded remarkable results, with 3.70 mg cyd-3-glu/L of anthocyanins and 78.90 mg GAE/mL of phenolic compounds achieved under optimal parameters (temperature: 45 °C, time: 90 min, ethanol concentration: 75% v/v). The anaerobic digestion process produced biogas with a methane content of 61.12%, highlighting the efficiency of this method. Additionally, the nutrient-rich digestate exhibited total soluble solids of 14.4% w/v, leading to biomass production in plant models that was 4.61 and 1.35 times greater than those without phosphorus fertilization or residue application. These findings underscore the biorefinery approach as a powerful tool for enhancing resource recovery while promoting sustainable agricultural practices. By demonstrating how agricultural residues can be transformed into marketable products, this research significantly contributes to the circular economy, supports local communities, and reduces reliance on synthetic inputs. Ultimately, it showcases a viable pathway for achieving sustainability and environmental stewardship through innovative waste valorization strategies.