Integrated microalgae cultivation and sustainable biofuel production from pretreated food waste

Repurposing of food waste (FW) affords an alternate waste management strategy and sustainable product yield. Thus, this study proposed an integrated biorefinery approach, repurposing pretreated FW hydrolysate for microalgae cultivation and utilizing residual solids for biomethane recovery. FW biomass with different solubilization ranging from (10-15 to 60-65%) obtained during surfactant coupled disperser pretreatment was used as a substrate for microalgae (Chlorella vulgaris) cultivation. A higher microalgae biomass productivity of 0.87 +/- 0.003 g/g substrate was obtained from the FW hydrolysate with 40-45% solubilization. The microalgae cultivated in FW hydrolysate with 40-45% solubilization yielded a higher protein, carbohydrate, and lipid accumulation of 380 +/- 20 mg/g, 480 +/- 30 mg/g and 360 +/- 15 mg/g. Besides, the methanogenesis process showed a higher methane yield of 0.294 +/- 0.003 L/g COD utilizing residual solids of pretreated food waste as substrate. This integrated biorefinery provides a sustainable platform for completely valorizing food waste biomass and recovery of multiple products.