Bioenergy recovery from biomass by-products is a promising approach for the circular bioeconomy transition. However, the management of agri-food by-products in stand-alone treatment facilities is a challenge for the low-capacity food processing industry. In this study, the techno-economic assessment of a small-scale anaerobic digestion process was evaluated for the management of jabuticaba by-product and the production of biomethane, electricity, heat, and fertilizer. The process was simulated for a treatment capacity of 782.2 m³ y⁻¹ jabuticaba peel, considering the experimental methane production of 42.31 L CH₄ kg⁻¹ TVS. The results of the scaled-up simulated process demonstrated the production of biomethane (13,960.17 m³ y⁻¹), electricity (61.76 MWh y⁻¹), heat (197.62 GJ y⁻¹), and fertilizer (211.47 t y⁻¹). Economic analysis revealed that the process for biomethane recovery from biogas is not profitable, with a net margin of −19.58% and an internal rate of return of −1.77%. However, biogas application in a heat and power unit can improve project feasibility, with a net margin of 33.03%, an internal rate of return of 13.14%, and a payback of 5.03 years. In conclusion, the application of small-scale anaerobic digestion can prevent the wrongful open-air disposal of jabuticaba by-products, with the generation of renewable energy and biofertilizer supporting the green economy toward the transition to a circular economy.

In this study, a Box-Behnken Design (BBD) has been used to optimize the recovery of bioactive compounds from jabuticaba (Myrciaria cauliflora) by-products through microwave-assisted extraction (MAE). Thus, the Box-Behnken (BBD) experimental design was followed by a response surface methodology (RSM) that would allow investigating the influence of the four independent variables (temperature, solvent composition, pH, and sample-solvent ratio) that have been considered. The results revealed that temperature and solvent composition (%MeOH) were the most significant factors regarding the yields of anthocyanins obtained from the studied plant matrix. The established optimized conditions and 10-min-extraction time resulted in yields of 9.70 ± 0.28 mg g⁻¹ of total anthocyanins. The method exhibited good repeatability and intermediate precision, with RSD variations lower than 5% for both parameters. The developed process was also able to extract and identify anthocyanins in commercial samples (jabuticaba pulp and jam). The results obtained from the optimized MAE method suggest that this technique is not only efficient for the recovery of anthocyanins from jabuticaba by-products, but it is also beneficial for a circular economy approach.