Filamentous Microalgae Screening for Carotenoid and Lipid Production: A Promising Candidate with High Ammonium Tolerance for Wastewater Treatment.

High-ammonium wastewater can be simultaneously remediated and valorized through phototrophic cultivation of stress-resilient microalgae. This study evaluated the growth performance of 16 microalgae strains (specific growth rate μ = 0.108-0.217 day) from different terrestrial habitats, recognizing that there is a high diversity of terrestrial microalgae, which could harbor species with unique metabolites and properties, among which Tribonema arborum HJX, Cephaleuros virescens LST0102, and Cephaleuros virescens 42.85 exhibited high biomass productivity, reaching up to 190.6 mg L day. Tribonema arborum HJX demonstrated the highest production of lipids and carotenoid, with a total of 46.9 and 2.51 mg L day, respectively. The tolerance of these strains to ammonium and low pH, along with their performance in a 10-L panel PBR, was then assessed. The results revealed that filamentous algae isolated from terrestrial habitats have significant potential for the co-production of lipids and carotenoids, as well as robust growth capabilities under high-ammonium and low-pH environmental stress. This study highlights the potential of terrestrial filamentous algae in co-producing high-value chemicals with high-ammonium wastewater.