Optimization of reducing sugars production from agro-residue coconut leaflets using autoclave-assisted HCl hydrolysis with response surface methodology

The utilization of coconut leaflets, an agro residue generated from coconut farming, was investigated to develop a process to release reducing sugars using hydrochloric acid (HCl)-assisted, autoclave-based hydrolysis. The variables affecting HCl hydrolysis (duration of autoclaving, concentration of HCl and weight of coconut leaflets) were screened using a one factor at-a-time approach. The duration of autoclaving and concentration of HCl both had significant effects on the hydrolysis process and the levels of these factors were further optimized using a central composite design with response surface methodology. The optimized conditions were 3.17% of HCl and 44.14 min of autoclaving that released the maximum reducing sugars of 29 g/L. A second order model was generated, which was a good fit with a coefficient of determination value of 0.83.