Conventional optimization of aqueous extraction of pullulan in solid-state fermentation of cassava bagasse and Asian palm kernel

•Pullulan was recovered from cassava bagasse and Asian palm kernel by Aureobasidium pullulans.•Effects of different factors on recovery of pullulan were studied.•Leaching kinetic study was performed.•The solid-liquid extraction constants for cassava bagasse and Asian palm kernel were found to be 0.1674 min−1 and 0.1443 min−1.

Solid-liquid extraction (leaching) is an important downstream processing step for the recovery of pullulan from solid state fermentation. In this study, pullulan was produced in a laboratory scale solid state fermentor (working volume 1.9 L) by Aureobasidium pullulans using cassava bagasse and Asian palm kernel as solid substrates. Pullulan was recovered from the substrate after fermentation by solid-liquid extraction. The effects of different factors, such as volume ratio of solvent and solid, pH of solvent, temperature of the system and agitation speed on the recovery of pullulan by Aureobasidium pullulans from solid state fermentation using cassava bagasse and Asian palm kernel as solid substrate. The leaching kinetics was followed and the first order rate constants for cassava bagasse and Asian palm kernel were found to be 0.167 min−1 and 0.144 min−1 respectively.