Optimization of Na2CO3 Pre-treatment by RSM Approach for Releasing Reducing Sugars from Cocoa Pod Shells

Cocoa pod shells (CPS) are underutilized agricultural lignocellulosic biomass. To release reducing sugars from cocoa pod shells, Na2CO3 pre-treatment was carried out. In the current study the conditions for sodium carbonate treatment were optimized by response surface methodology (RSM). The screening of (CPS weight, Na2CO3 concentration, time, rpm) affecting release of reducing sugars was carried out by one factor at a time (OFAT) approach. Among the four factors screened, CPS weight and Na2CO3 concentration showed significant effect on the pre-treatment process. These significant factors were opti mized by RSM using a central composite design (CCD). At the optimized conditions of 7.82 g of CPS and Na2CO3 concentration of 0.58 N, the yield of reducing sugar was found to be 0.94 g/L. A second order model was generated and validated, which was found to be of good fit with an R2 of 0.847. These results show that RSM is an efficient methodology for rapid optimization of influencing parameters and development of polynomial equation for modelling the pre-treatment process.