Enzymatic hydrolysis of cocoa residues to obtain sugar platforms: kinetic study and mathematical modeling.

Abstract

Agroindustrial waste has the potential to be a source of energy, chemicals, and materials without interfering with the production of primary foods. With the significant increase in cocoa consumption, the production of this product has also grown, resulting in an accumulation of waste that makes up 70 to 80% of the biomass. Cocoa pod husk is the leading waste generated from fruit processing, and its interest is due to its high nutritional value due to the presence of a variety of compounds, such as phenolic compounds and dietary fibers. In this context, this scientific initiation project aims to conduct a kinetic study of the enzymatic hydrolysis of cocoa pod husk to obtain sugar platforms that can be used in the biorefinery concept for energy and chemical products. This project will be developed within the 2023/17175-0 scope, approved in the FAPESB-FAPESP call, no 010/2023. Initially, raw cocoa residues will be subjected to pretreatment under different operating conditions, aiming to identify the combination that results in a solid fraction rich in cellulose and a liquid fraction rich in pentoses. For this, an experimental design will be carried out to evaluate the effects of acid concentration (ranging from 0.5% to 3% m/m) and reaction time (from 10 to 90 minutes). Enzymatic hydrolysis experiments will be performed with pre-treated biomass under optimized conditions using the commercial cellulase Cellic®Ctec2. The influence of enzyme and substrate concentrations will be evaluated, varying the biomass load from 2.5 to 10% (m/v) in initial and long-term velocity assays. The enzyme concentration will be varied from 5 to 80 filter paper units (FPU)/gcellulose. With the kinetic data obtained, it will be possible to adjust the Michaelis-Menten (MM) and modified MM models, with and without competitive inhibition by glucose. These adjusted models can identify the main characteristics of the hydrolysis process and can be extremely useful within the perspective of bioreactor engineering.