Abstract

Simple SummaryThis study explored how to improve the ability of microalgae to clean wastewater by efficiently absorbing nitrogen (N) and phosphorus (P), which are essential for plant growth but can also cause water pollution. By focusing on the green algaChlamydomonas reinhardtii, they discovered that overexpression of a specific gene,DUR3, significantly improves urea uptake. This enhanced absorption leads to better growth and optimizes photosynthesis under various N conditions. Moreover, it increases the alga’s capacity to simultaneously take up both N and P from mixed nutrient sources, although this P enhancement is absent under pure-urea conditions. The research uncovered thatDUR3overexpression triggers a coordinated network of processes within the algae, including nutrient metabolism, photosynthesis, and carbon transport, leading to significant improvements in nutrient uptake efficiency. These findings highlightDUR3as a key genetic target for developing microalgae strains capable of efficient wastewater bioremediation and contributing to nutrient recycling, offering sustainable strategies for managing water pollution and resource recovery.Nitrogen (N) and phosphorus (P) are essential macronutrients for plant growth and major pollutants driving aquatic eutrophication. Microalgae represent a sustainable biological platform for nutrient recovery and circular utilization from wastewater; however, the molecular mechanisms governing efficient urea assimilation and its coordination with phosphorus uptake remain inadequately characterized. This study investigated how overexpression of the high-affinity urea transporter geneDUR3enhances nutrient scavenging capacity in the model green algaChlamydomonas reinhardtii. TheDUR3-overexpressing line exhibited concentration-dependent growth responses to urea, showing significant promotion at low-to-moderate levels but inhibition at high urea concentration or under pure-urea conditions, whereDUR3-overexpressing (DUR3-OE) was more