Photoprotection comes at a cost: growth-productivity trade-offs associated with enhanced NPQ in Haematococcus lacustris.

Enhanced NPQ in Haematococcus lacustris mutant A116 is linked to decreased photosynthetic efficiency and reduced growth and astaxanthin productivity under high CO2 conditions.

• Why it matters: Understanding the balance between photoprotection and productivity is crucial for optimizing microalgal cultivation for bioproducts like astaxanthin, especially under varying environmental conditions.
• What they did: Researchers isolated and characterized the NPQ-enhanced mutant A116 through cultivation assays, photosynthetic parameter analysis, pigment profiling, and whole-genome resequencing, comparing its performance under different stress and carbon regimes.
• The result: The study found that increased NPQ supports high-light tolerance under carbon limitation but reduces growth and productivity when carbon fixation is efficient, implying that tuning photoprotection to environmental conditions can optimize algal productivity.