Harnessing Algal Biorefineries for Waste to Wealth Paradigm: A Pathway Toward Circular and Sustainable Bioeconomy

ABSTRACT At present, the increasing discharge of hazardous and toxic pollutants into freshwater bodies has become a major global concern due to its detrimental effects on human health and aquatic ecosystems. The growing challenges and a complex suite of problems related to water pollution and scarcity demand technological innovations, reuse strategies, and sustainable solutions. Therefore, developing efficient, affordable, and eco‐friendly wastewater treatment technologies is crucial. An oleaginous photosynthetic organism “microalga” has emerged as a valuable feedstock for wastewater treatment, carbon neutrality, and nutrient recovery. On the other hand, setting up microalgal biorefineries support resource recovery and biomass utilization, offering diverse bio‐based products across industries. For instance, the global microalgal biofuel market is projected to reach USD 8.7 billion by 2030, while microalgal nutraceuticals including omega‐3 fatty acids already command a market value of over USD 2.5 billion annually, with pigments like astaxanthin valued at USD 1500–7000 per kg. Similarly, microalgal biomass for biofertilizers and animal feed additives contributes to a market share exceeding USD 1.2 billion globally. This multifaceted approach facilitates the reduction of waste generation by enhancing production of microalgae bioproducts. Unlike terrestrial crops like soybean that require 2000–3000 L of freshwater per kg biomass, microalgae cultivation in wastewater systems can reduce the water footprint to less than 100 L per kg biomass, achieving > 95% reduction in freshwater demand. Keeping this in mind, present review instigates the integrated phycoremediation approach that aligns with circular economy goals, promoting resource recovery and reducing the carbon footprints and water footprints in the framework of regenerative and zero waste valorization.