Enzymatic Synthesis of Aroma Ester Catalyzed by Lipases Immobilized on Activated Carbon Derived from Fermented Cocoa Bean Shells

This study explored the production of activated carbon from cocoa bean shells (CBS), both before and after solid-state fermentation, and evaluated its potential as a support for enzyme immobilization in aroma ester synthesis. Fermentation improved the physicochemical properties of the shells, increasing surface area and porosity of the resulting activated carbon. Activated carbon from fermented shells (AC-FCBS) displayed a surface area of 1158 m2/g, compared to 1050.30 m2/g for nonfermented shells (AC-CBS). These supports were tested for immobilization of Amano Lipase PS (APS), achieving relative activity yields of 72% ± 0.11 for AC-CBS, 82% ± 0.16 for AC-FCBS, and 85% ± 0.20 for the commercial resin Diaion HP-20 (DIR). In esterification reactions, APS immobilized on AC-FCBS reached 85% yield, surpassing the 75% obtained with AC-CBS. Regarding operational stability, APS-AC-FCBS retained 95% of its initial activity after five cycles and showed only a 5% reduction in conversion after seven cycles, whereas APS-DIR lost 30% under the same conditions. Notably, competitive results were achieved with lower enzyme concentrations (3 mg/g of support), highlighting the efficiency of the developed material. Overall, AC-FCBS proved to be a promising, low-cost, and effective support that enhances enzyme performance, valorizes agro-industrial residues, and contributes to sustainable esterification processes. These outcomes align with the United Nations Sustainable Development Goal 12 (Responsible Consumption and Production), promoting resource efficiency, waste reduction, recycling, and circular economy practices.