Microwave-assisted pretreatment of wet microalgal biomass for recovery of biofuel precursors

Abstract

Pretreatment of microalgal biomass is essential for the maximal recovery of biofuel precursors packed inside the complex microalgal cell wall. In the present work, microwaves were exploited for efficient pretreatment of wet microalgal biomass. A response surface methodology – Box Behnken design (RSM-BBD) was utilized to obtain the optimum conditions for biomass pretreatment, and a mathematical model was devised. Using the designed experimental setup, the optimum conditions were obtained as 5 min of microwave irradiation time, 700 W output power, and 2 gL-1 microalgal biomass concentration. The model was further validated experimentally. The pretreatment results were confirmed qualitatively through microscopic observations and quantitatively in terms of sugar release and lipid extraction. The optimum conditions were found promising to enhance the lipid extraction by 55.32% compared to the untreated condition. Additionally, the present design showed the importance of water as a green solvent for biomass pretreatment under microwave irradiation. Overall, the current attempt facilitates a cost-effective, green methodology for wet microalgal biomass pretreatment in a short duration.