Next-generation microalgae biorefinery: innovations in sustainable astaxanthin, biofuel, and aquafeed production

Abstract

Microalgae are a promising platform for sustainable biorefinery applications due to their ability to produce a diverse array of high-value metabolites. Among these, astaxanthin has garnered significant interest for its potent antioxidant properties and extensive industrial relevance. However, large-scale production is limited by low biomass productivity, inefficient bioprocess strategies, suboptimal astaxanthin accumulation conditions, and energy-intensive harvesting techniques, leading to high operational costs. This review presents a comprehensive and advanced perspective on astaxanthin biorefinery by integrating cultivation optimization, bioprocess intensification, and innovative downstream processing. The study explores advancements in bioprocess engineering, metabolic regulation, and novel extraction techniques to enhance astaxanthin yield while minimizing resource inputs. Furthermore, the valorization of residual biomass post-extraction for sustainable fish feed and/or biofuel development is examined, offering a circular approach to waste reduction and resource efficiency. By adopting an integrated systems approach, this review addresses scale-up challenges and provides sustainable solutions for efficient astaxanthin production while contributing to aquaculture sustainability. The findings contribute to the development of a next-generation microalgal biorefinery that maximizes product recovery, minimizes waste, and strengthens the role of microalgae in a green bioeconomy. The subject aligns with multiple United Nations' Sustainable Development Goals by promoting sustainable astaxanthin production, resource efficiency, and circular bioeconomy principles: SDG 9 (Industry, Innovation, and Infrastructure), SDG 12 (Sustainable Production), and SDG 13 (Climate Action).

Keywords

Microalgal biorefinery / Astaxanthin / Aquafeed / Biorefinery / Sustainability / Circular economy / Waste valorization

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