Microwave assisted transesterification of waste frying oil and concentrate methyl ester content of biodiesel by molecular distillation

► Waste cooking oil was utilized for biofuel production. ► Biodiesel was obtained from waste cooking oil by transesterification reaction. ► Transesterification reaction time was reduced using microwave heating system. ► Methyl ester content of biodiesel was enriched by molecular distillation. ► Optimum distillation conditions were determined using 4 × 3 factorial design.