Response surface optimisation of enzymatic hydrolysis of cassava peels without chemical and hydrothermal pretreatment

Cassava peel is a feedstock of significant potential for bioprocessing into industrial products. Its economic utility has however not been explored despite its advantages over traditional first-generation biomass feedstock. We demonstrate in this study that cassava peel can be hydrolysed to produce glucose at very high efficiency without chemical or hydrothermal pretreatment. We evaluated the conversion efficiency of a one-step simultaneous hydrolysis of the peel with mixed enzymes. Response surface methodology was applied to optimise the hydrolysis condition for maximum glucose recovery. Glucose concentration was measured by HPLC-IR and polynomial regression models defining the process parameters fitted to predict the optimal setting of process variables for maximum glucose recovery. Maximum glucose recovery was predicted to occur at pH 4 and 54.75 degrees C with an enzyme mixture containing 10 FPU/g cellulase, 0.5 U/g beta-glucosidase, 50 U/g amyloglucosidase, and 50 U/g alpha-amylase. Validation experiments confirmed that up to 95.48% glucose can be recovered from 0.06 g/ml of cassava peel in 43.15 h at these factor settings. Overall, the empirical models developed present an efficient tool for glucose recovery at high conversion efficiency. This model could be used for large-scale industrial production of glucose from cassava peel without the cost of pretreatment.