Microalgae as Novel Food Resources: Technological Breakthroughs, Application Bottlenecks, and Future Pathways

Global population growth and the demand for sustainable food systems have pushed microalgae into the spotlight as promising novel food resources. They are rich in protein, omega-3 fatty acids, and bioactive pigments including astaxanthin and phycocyanin. Unlike conventional farming, microalgae cultivation can be conducted on non-arable land and may reduce direct competition with conventional food crops for land resources, depending on the production system used. Regulatory progress in China, the European Union (EU), and the United States has resulted in the authorization or approval of several microalgal species and microalgae-derived ingredients for specific food and nutritional applications, including dietary supplements, infant nutrition products, and alternative protein ingredients. Despite these advances, broader commercial adoption remains constrained by several challenges, such as off-flavors and the dark green color, high production costs from closed photobioreactors and energy-intensive downstream purification, fragmented regulatory frameworks across jurisdictions and limited long-term data on bioavailability, allergenicity, safety, and dose–response relationships for some emerging strains. This review focuses on microalgae as novel food resources, covering regulatory approvals, strain selection, high-value utilization, and market translation, synthesizes evidence on nutritional evaluation, application scenarios, and global regulatory differences, analyzes key bottlenecks, and proposes pathways to bridge fundamental research with industrial practice. It also highlights unresolved knowledge gaps to guide future research and policy.