From blooms to bioprocesses: Temperature and light modulate growth, protein and carbohydrate content, and metabolome of Aphanothece strains

This study evaluated the interactive effects of temperature and light intensity on growth, macromolecular composition and the metabolome of two bloom-forming cyanobacteria, Aphanothece microscopica RSMan92 and A. stagnina RSMan2012, originally isolated from the Patos Lagoon estuary. Using a full factorial design, with temperatures of 12, 20 and 28 °C and light intensities of 60, 120 and 180 μmol m −2 s −1 , we monitored cell density, total protein and total carbohydrate over 24-day cultivations and applied untargeted 1 H NMR metabolomics at the stationary phase. Data were analyzed through polynomial modelling, PCA, PLS-DA and hierarchical clustering to resolve species-specific and treatment-driven responses. Temperature was the dominant driver of growth, macromolecular allocation and metabolite composition, while light intensity and its interaction with temperature defined species-specific optima: A. microscopica attained its highest cell densities under warmer conditions combined with lower irradiance, and accumulated larger protein fractions under warm, moderate-to-high light regimes; A. stagnina exhibited superior growth at high temperature and irradiance and tended to accumulate carbohydrates under low temperature and low light. NMR profiles revealed depletion of nucleotides, glutathione and choline under cold treatments, along with divergent enrichment of selected amino acids and compatible solutes under favorable regimes. These results demonstrate substantial metabolic plasticity and interspecific divergence within the genus Aphanothece , indicating that the intrinsic proliferative traits of bloom-forming cyanobacteria can be deliberately selected and exploited in the laboratory to optimize biomass and target metabolite yields. Collectively, these findings provide actionable cultivation parameters to guide growth regime design for applied phycology and biotechnological development. • Temperature was the main driver of growth and metabolic profiles in Aphanothece spp. • microscopica grew best at warm, low-light conditions, favoring protein synthesis. • stagnina thrived under high temperature and irradiance, accumulating carbohydrates. • 1 H NMR profiling showed species-specific shifts in nucleotides and osmolytes.