Food Science and Agriculture: Research Highlights Vol. 10

Microalgae and commercially allied microorganisms are increasingly proposed as resources for proteins, long-chain polyunsaturated fatty acids, pigments and functional carbohydrates in human food and animal feed. Yet the distance between compositional promise and cost-competitive, safe, acceptable products remains substantial. This critical narrative review integrates evidence across resource selection, cultivation, downstream processing, nutritional bioaccessibility, food formulation, feed performance, safety, regulation, techno-economics and environmental assessment. Literature published from 1 January 2000 to 4 July 2026 was considered, with older studies retained only when conceptually necessary. The evidence shows that commercial maturity is concentrated in a small number of biomass and high-value ingredient categories, whereas emerging taxa such as Tetraselmis, Nannochloropsis, Phaeodactylum tricornutum, Euglena gracilis, Galdieria sulphuraria and Chlamydomonas reinhardtii remain at uneven stages of nutritional, technological and regulatory validation. No cultivation platform is intrinsically optimal: open systems can reduce capital intensity but increase contamination and variability risks; closed photobioreactors provide greater control at higher cost and energy demand; and heterotrophic fermentation can achieve high cell densities but transfers environmental and economic burdens to carbon substrates and sterile operation. Downstream processing frequently determines whether nutrients are bioaccessible and whether ingredients are sensorially and functionally usable, but intensive disruption, extraction and drying can erode cost and sustainability advantages. Feed evidence is strongest in aquaculture, where microalgal proteins and lipids can replace defined fractions of fishmeal or fish oil under formulation-specific conditions, while broad generalisation across species and life stages remains unwarranted. Commercialisation therefore depends on product-specific matching of organism, cultivation mode, processing severity, end-use specification and regulatory pathway. Future progress requires strain-by-process optimisation, standardised nutritional assessment, realistic pilot-scale techno-economic and life-cycle data, safety-by-design for circular substrates, and trials that test foods and feeds at commercially relevant inclusion levels rather than compositional potential alone.