Recent advances in biotechnological valorization of agro-food wastes (AFW): Optimizing integrated approaches for sustainable biorefinery and circular bioeconomy

Achieving renewable clean energy to meet increasing global demand and counter overreliance on depleting unsustainable sources has recently drawn significant research interest. Similarly, to attain the sustainable development goals (SDGs) "zero hunger" agenda, massive agricultural/food productions are embarked on, leading to increased agro-food waste (AFW) generation with enormous handling costs to evade its contribution to environmental pollution. The advent of biorefineries has fostered a healthy balance for tackling challenges from AFW and unsustainable energy - thereby promoting circular bioeconomy (CBE). Integrating several emerging microbial/enzymatic bioconversion processes has facilitated the overall increase in process efficiency. This review, therefore, provides extensive information on the ecological and environmental impacts of AFW, as well as its biorefinery processes for a circular bioeconomy and environmental sustainability. We also critically reviewed advances in integrated bioconversion processes and microbial/enzymatic engineering for AFW valorization. Finally, limitations and prospects for real-life application of these recent approaches were suggested.