Prefeasibility analysis of small-scale biorefineries: the annatto and açai case to improve the incomes of rural communities

The industrial applicability of exotic and wild fruits has been investigated as stand-alone processes framed to obtain a single main product. However, their combination and the valorization of the processing residues in a biorefinery scheme have not been explored. Therefore, this work aims to assess the technical and economic feasibility of small-scale biorefineries based on annatto and açai as raw materials. Therefore, the actual processing of both fruits was carried out experimentally. For annatto, the abrasion extraction of dye paste was performed, obtaining mass yields of up to 58.4% by working with ground seed. Regarding the açai, the pulp was obtained with a polyphenol content of 23.56 mg of gallic acid equivalent per gram of sample. The residues generated in both processes were used as substrates for biogas production, achieving biomethane yields between 186 and 533 mL gTVS −1 . These results were the basis for designing and simulating process scale-up in biorefinery contexts. Five scenarios were evaluated, involving the production of annatto dye paste, açai pulp, biogas from exhausted annatto seeds, slurry and seeds of açai, and feedstock integration. As the main energy result, it was found that the scenarios contemplating biogas production can supply thermal energy to more than 1400 households. From the economic perspective, it was found that economic feasibility is reached at flows below the national production in Colombia for all scenarios. This work demonstrated that small-scale biorefineries based on the processing of tropical forest fruits are an opportunity to improve the life quality of communities through the coupling of techno-economic results with social and governmental needs to strengthen the value chains of low-technified fruits in agribusiness.