Response surface methodology based optimization of sorbitol production via solid state fermentation process

To optimize sorbitol production through solid state fermentation (SSF) process using response surface methodology (RSM), the central composite design (CCD) was employed in this study in order to minimize the number of experiments needed for the determination of the best combination of parameters for the process optimization. The raw material used in this study was Meranti wood sawdust (MWS) obtained from Gambang Sawmill (M) Sdn Bhd, Gambang Kuantan, Pahang. The type of bacteria used for the study was Lactobacillus plantarum (BAA 793; NCIMB 8826), purchased from the America Type Culture Collection (ATCC). The physical and chemical pretreatment methods were used in the study to recover cellulose from the MSW, followed by the enzymatic hydrolysis process to produce glucose. The last phase of this work was the fermentation process using SSF to convert the produced glucose to sorbitol; this is the section of the study where the parameters were optimized using the RSM. The result of the RSM studies showed that the interactions between moisture content and temperature had a very significant effect with an F value of <0.0001. The highest yield of sorbitol (29.0625 g/L) was obtained when using 50% of moisture content, at a temperature of 35 °C for 10 h of fermentation time. The RSM helped in the optimization of the effective parameters as well as to analyze the interaction between the parameters.