Green bioprocessing and applications of microalgae-derived biopolymers as a renewable feedstock: Circular bioeconomy approach

An expeditious pace of expanding industrialization and urbanization is a global vulnerability which immediately requires utmost attention towards the replacement of prosaic petroleum-based polymer assimilation. Thus, greening the innovative route of microalgae derived biopolymers has attained significant interest as an improved and sustainable approach towards the worldwide circular bioeconomy. In this context, the use of as synthesized biopolymers from microalgae attributing as a potential feedstock has bestowed for a biodegradable solution to reduce the greenhouse gases emission and rapid biomass productivity with metabolic flexibility. However, the confront of high microalgae cultivation cost and low metabolites’ accumulation have triggered the advancement of microalgae metabolic cultivation strategy. Hence, the current review portrays to propose a novel multi-phasic fed batch light depleted low-cost wastewater cultivation approach and a clear mechanistic phenomenon for accelerating the biopolymer production. This review also provides a comprehensive summary on several microalgae strains which are capable for biopolymer synthesis and various effective extraction techniques to isolate the biopolymers. The future endeavour and challenges on the microalgae circular bioeconomy which involves the current issues regarding the cell harvesting method, scale up and bioprocessing cost of microalgae cultivation have been highlighted. The applications for microalgae derived biopolymer in industrial and nutraceutical sectors have also been emphasized. This review is expected to bring new insights to the industrial stakeholders for further advancement of microalgae-based biopolymer field economically, and eventually contributing towards environmental sustainability.