Box-Behnken-Design based optimization strategy for alkaline pretreatment of palm oil mill effluent for producing reducing sugar

Alkaline pretreatment is used as a substrate prior to subsequent biological processes for palm oil mill effluent (POME) treatment. In the present study, Sodium hydroxide (NaOH) was used to recover reducing sugar from POME. Important process parameters, such as reaction time (min), reaction temperature (°C), and concentration (%) (w/v), were optimized using Box-Behnken Design in Response Surface Methodology (RSM). POME treated with NaOH yielded the reducing sugar of up to 3640.84 mg/L under the optimum conditions of 58.78 min, 77.06°C, and 2.58% (w/v) for reaction time, reaction temperature, and concentration of NaOH, respectively. The analysis of variance (ANOVA) indicated that the quadratic model for reducing sugar production had an R2 coefficient of 0.979. Conformity testing for optimum conditions proved the validity of the model, yielding reducing sugar at a 9.35% increase, relative to untreated POME. This study verified the importance of statistical tools such as RSM for enhanced reducing sugar production from the industrial waste stream (POME) and its usefulness and efficiency in energy conversion.