Abstract
Microalgae are increasingly recognized as industrial biotechnology platforms for the sustainable production of high-value products (HVPs), including carotenoids, polyunsaturated fatty acids (PUFAs), polysaccharides, and phycobiliproteins. Their transition from exploratory biomass resources to precision metabolite-focused biofactories reflects growing industrial and regulatory consolidation. This review adopts a product-oriented perspective that moves beyond biomass productivity to evaluate how biological regulation, cultivation strategies, downstream processing, safety assessment, and regulatory readiness collectively determine industrial feasibility and commercialization potential. Rather than treating these components independently, the analysis frames them as interconnected determinants within a systems-level bioindustrial design framework. Emphasis is placed on stress-responsive biosynthesis, extraction and purification bottlenecks, mixotrophic cultivation, and strain engineering approaches as key enablers for improving productivity, process robustness, and cost performance. Carotenoids and omega-3 PUFAs are identified as the most industrially mature microalgal HVPs, supported by scalable production systems and regulatory acceptance, whereas polysaccharides and phycobiliproteins are highlighted as emerging products with expanding bioindustrial relevance. This comparative positioning underscores that industrial maturity depends not solely on biological potential, but on coordinated optimization across strain design, cultivation stability, downstream compatibility, and compliance pathways. By integrating technological innovation with safety and regulatory considerations, this review provides a coherent framework to support scalable, compliant, and sustainable microalgal biomanufacturing. Overall, the synthesis advances a rational roadmap for translating microalgal HVPs from laboratory optimization to economically viable and regulation-ready industrial deployment.