Harnessing microalgal proteins as sustainable bioactive ingredients for cosmetics: green extraction, functionalization, and advanced delivery systems

Abstract In recent years, microalgae have emerged as sustainable biofactories for synthesizing high-value metabolites, with proteins such as mycosporine-like amino acids (MAAs), phycobiliproteins, and bioactive peptides garnering significant attention as eco-friendly alternatives to synthetic cosmetic ingredients. This review critically evaluates the multifunctional bioactivities of microalgal proteins for cosmeceutical applications, with a particular focus on photoaging, including UV photoprotection, antioxidant, anti-melanogenic and anti-inflammatory effects, as well as other properties like antimicrobial and natural dyeing functions. Additionally, this review explores advancements in environmentally sustainable extraction technologies, including ultrasound-assisted, microwave-assisted and pulsed electric field (PEF) techniques, as well as the integration of green solvents (i.e., ionic liquids (ILs) and deep eutectic solvents (DES)) and enzymes that address key limitations of conventional methods, such as high energy requirements, low scalability, and protein degradation. This review also examines innovative functionalization strategies, notably enzyme hydrolysis and nano- and micro-encapsulation systems. These approaches enhance the stability, bioavailability, compatibility and bioactivities of microalgal proteins in cosmetic formulations. By integrating insights into the high protein yields of industrially relevant microalgae species, their diverse biofunctional properties, and cutting-edge processing techniques, this review positions microalgal proteins as next-generation, sustainable ingredients poised to revolutionize the cosmetics industry. The synthesis of biological efficacy, green chemistry principles, and technological innovation underscores their potential to meet rising consumer demand for natural, non-toxic, and high-performance cosmetic solutions.