Optimization of Pre-treatment Process of Cocoa Pod Husk Using Various Chemical Solvents

Abstract

The purpose of research is to see the effect of type of reagent (NaOH, H 2 O 2 and H 2 SO 4) and the condition of pretreatment of cocoa pod husk towards lignin content after pre-treatment and hydrolysis, reducing sugar and total sugar content. Response Surface Method (RSM) was used to optimize process conditions of pre-treatment (delignification). Hydrolysis for all pretreated sample were carried out using 3% H 2 SO 4 with a ratio of cocoa pod husk to solvent (1:10) for 2 hours at a temperature of 110 o C using an autoclave. The chemical pre-treatment with NaOH was optimized by varying the concentrations of NaOH (4-8% (w/v), centre point: 6%), reaction time (60-100 minutes, centre point: 80 minutes) and ratio of biomass to solvent (1:15-1:25, centre point 1:20 w/v). The optimum conditions in this study was at the concentration of NaOH (X 1) of 4% w/v, reaction time (X 2) of 100 minutes; ratio of biomass/solvent (X 3) of 1:25 (w/v). The lignin content after pre-treatment was 15.03% lignin, lignin content after hydrolysis was 19.57%, 11.75% of reducing sugar, and 12.78% of total sugar. The chemical pre-treatment with alkaline peroxide (H 2 O 2) was optimized by varying the concentrations of H 2 O 2 (4-7% w/v, centre point 5.5% (w/v)), reaction time (40-90 minutes, centre point: 65 minutes), and ratio of biomass/solvent (4-7% w/v). The optimum conditions in this study was at the concentration of H 2 O 2 concentration (X 1) of 5.52% w/v, reaction time (X 2) of 61.97 minutes, biomass loading in solvent (X 3) 7% w/v. The lignin content after pre-treatment was 8.759, lignin content after hydrolysis was 25.029%, 8.169% of reducing sugar, and 10.371% of total sugar. The chemical pre-treatment with H 2 SO 4 was optimized by varying the concentrations of H 2 SO 4 (0.5-1.5% w/v), reaction time (60-120 minutes, centre point: 90 minutes), and ratio of biomass to solvent (1:4-1:6 w/v, centre point 1:5 w/v). The optimum conditions was reached without hydrolysis. The optimum condition this study is at the H 2 SO 4 concentration (X 1) of 1.5%, reaction time (X 2) of 120 minutes, ratio of biomass/solvent (X 3) of 6%. The lignin content after pre-treatment was 18.8%, 15.59% of reducing sugar and 20.49% of total sugar.

Valorisation strategies for cocoa pod husk and its fractions

“…Pre-treatment of CPH has been carried out using chemicals, e.g., acidic or alkaline or organic solvents, to enhance the release of cellulose and obtain more fermentable sugars [43].…”

“…Previous studies revealed that the lignin content of CPH reduced from 34% to 15% with the following alkali pre-treatment condition: 4% (w/v) NaOH, reaction time of 100 minutes with ratio of biomass/solvent of 1:25 (w/v) [43]. Mild organosolv protocol involves a relative short exposure to high concentration of butanol (95%), with acid (HCl) acting as a catalyst.…”

Synthesis of Bioethanol from Cocoa Pod Husk Using Zymomonas Mobilis

“…This hydrolysis process using H2SO4 solution with 10% (v/v) of concentration yields the product with 9.89% (v/v) of glucose content. This result is quite smaller than Nazir et al study which cocoa pod husk was treated by the same acid solution yet with different concentration (1.5%w/v) resulting 15.59% of glucose content as reducing sugar [10]. Table 1.…”

Application of Response Surface Method in Reverse Osmosis Membrane to Optimize BOD, COD and Colour Removal from Palm Oil Mill Effluent

“…Other important terms are the accuracy and variability of the models, which can be evaluated according to the R-Squared (R2) value which is between 0 to 1. If the value closer to1 means a better prediction of the response [16,17]. The R2 of the CCD models showed a higher value, which were 0.9801, 0.9936 and 0.9745 for COD, BOD, and Colour, respectively.…”