Harnessing microalgae for protein production: advances, functional properties, and industrial potential

• Microalgae provide a high-yield, sustainable protein alternative. • Optimized cultivation boosts microalgal protein content and yield. • Microalgal proteins enhance emulsification, foaming, and gelation. • Advanced extraction improves protein recovery and reduces costs. • Cost and scalability challenges must be addressed for industry use. The escalating global population and rising demand for sustainable protein sources necessitate alternative solutions beyond traditional livestock and crop-based proteins. Microalgae have emerged as a promising protein source due to their high protein content (30–55 % dry weight), superior amino acid composition, and environmental benefits. Unlike conventional protein sources, microalgae can be cultivated on non-arable land using seawater, minimizing resource competition and reducing carbon emissions. Additionally, microalgal proteins exhibit promising functional properties, such as emulsification, foaming, and gelation, which have been demonstrated in selected species and highlight their potential in diverse food applications. Advances in microalgal cultivation strategies, such as mixotrophic and heterotrophic modes, have significantly improved protein yield. Moreover, biotechnological enhancements, including metabolic engineering and bioreactor optimization, have further increased their commercial viability. The sensory limitations can be alleviated through depigmentation, deodorization, and formulation strategies, thereby improving the food applicability of microalgal proteins. However, challenges such as high production costs and scalability barriers hinder large-scale adoption. Unlocking the microalgal potential as an alternative protein source will require advancements in cultivation efficiency, extraction methods, and cost reduction strategies. This review explores recent progress and emerging approaches to harnessing microalgal proteins for sustainable food and biotechnology applications.