Microalgae and Cyanobacteria as Photosynthetic Microbial Factories: Taxonomy, Biochemical Potential, and Emerging Bioindustrial Applications

Microalgae and cyanobacteria are increasingly recognized as versatile photosynthetic microorganisms with substantial potential to support sustainable bioindustrial systems. Their taxonomic diversity, rapid growth rates, and capacity to synthesize proteins, lipids, pigments, and other high-value metabolites have positioned them as promising alternatives to conventional biological resources. Despite extensive experimental research, the evidence remains fragmented across species, cultivation strategies, and application domains, limiting cross-study comparability and informed decision-making. This study presents a systematic review and meta-analysis aimed at synthesizing current knowledge on the taxonomy, biochemical potential, and applied performance of microalgae and cyanobacteria as photosynthetic microbial factories.A comprehensive literature search was conducted across major scientific databases, and eligible studies were screened, selected, and analyzed following PRISMA guidelines. Quantitative data on biomass composition, metabolite production, and application-specific performance metrics were extracted and standardized. Random-effects meta-analytical models were applied to account for biological and methodological heterogeneity across studies. Forest plots were used to estimate pooled effects, while funnel plots were employed to explore reporting consistency and potential small-study effects.The synthesis reveals substantial variability in biochemical yields and application outcomes that can be attributed to taxonomic identity, cultivation conditions, and system design. Protein-rich taxa such as Arthrospira and Chlorella dominate nutraceutical applications, while lipid-specialized groups underpin emerging energy and biorefinery concepts. Environmental applications, including wastewater treatment and bioelectrochemical systems, demonstrate integrative potential but remain constrained by scale-up challenges. Overall, this review provides a structured, evidence-based framework linking organismal diversity to functional performance, supporting more rational development of microalgae- and cyanobacteria-based biotechnologies.