Statistical optimization of thermal pretreatment conditions for enhanced biomethane production from defatted algal biomass

The present study analyzes the effect of thermal pretreatment for enhancing the biomethane potential of defatted algal biomass of Scenedesmus dimorphus through statistically guided experimental design. To this end, defatted microalgal biomass at various concentrations (1, 3 and 5 g L−1) was pretreated at elevated temperatures (100, 120 and 150 °C) for 20, 40 and 60 min. The solubilised TOC was favourably enhanced up to 71 mg L−1 after pretreatment at a temperature of 150 °C for reaction time of 60 min. The methane yield was substantially enhanced (up to 60%) and could be correlated with an increase in organic matter solubilisation and enhanced biodegradability via thermal pretreatment. The optimisation of the integrated thermal pretreatment-biomethanation process resulted in up to 1.6-fold increase in methane yield.