Algal Biorefineries: Emerging Platforms for Circular Bioeconomy and Sustainable Bioproduct Generation

Abstract

Growing concerns regarding fossil fuel depletion, greenhouse gas emissions, and environmental sustainability have accelerated the development of renewable biomass-based technologies. Among these, algal biorefineries represent an innovative and sustainable platform to transform algal biomass into various services of high added value products in a circular bioeconomy context. In contrast to traditional petroleum refineries, algal biorefineries employ microalgae and macroalgae as sustainable feedstocks for the simultaneous production of biofuels, biochemicals, biomaterials and bioenergy. This review gives an overview of the recent progress in algal biorefinery systems focused on biomass cultivation, harvesting, fractionation, and conversion technologies.It also elaborates on major algal biorefinery approaches, covering the feedstock used and bio-based products derived from microalgal, macroalgal, integrated whole-biomass algal, and wastewater-based systems. Include important conversion pathways (e.g., transesterification, fermentation, anaerobic digestion and thermochemical processing) for the production of biodiesel bioethanol biogas and renewable chemicals. Not only is utilized for bioenergy production, algae are essential sources of other high-value compounds such as proteins, pigments, antioxidants and polyunsaturated fatty acids which are useful in food (as alimentary supplements), pharmaceutical or nutraceutical industries. Several issues remain with regards to the efficiency of cultivation, harvesting and processing techniques as well as commercial viability, despite technological advancements. Algal biorefineries present important opportunities for sustainable biomass valorisation, and are a critical component of future low carbon circular bioeconomy pathways.