Simultaneous promotion of photosynthesis and astaxanthin accumulation during two stages of Haematococcus pluvialis with ammonium ferric citrate

To simultaneously promote biomass yield and astaxanthin content of Haematococcus pluvialis, ammoniumferric citrate (AFC) was employed to stimulate light harvest in photosynthesis during the green stage and oxidation induction in astaxanthin accumulation during the red stage. AFC not only improved chlorophyll synthesis by 22.5% to provide more electrochemical potential energy in the green stage, but also alleviated photosystem II damage to maintain a high level of effective quantum yield by enhancing carotenoid production. The citrate derived from AFC stimulated acetyl-CoA and NADPH production through citric acid cycle and transaminase cycle during the red stage, resulting in an increased lipid content by 1.77-fold. The astaxanthin content in H. pluvialis cells cultivated with 5 mu M AFC was 12.5% higher than that without AFC, which was attributed to severe oxidative stress caused by AFC through Haber-Weiss reaction. These results provided a new approach to reduce emission of greenhouse gasses with producing high-value products. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

Ammoniumferric citrate (AFC) was used to enhance biomass yield and astaxanthin content of Haematococcus pluvialis by stimulating light harvest in photosynthesis and oxidation induction in astaxanthin accumulation at different growth stages. This resulted in increased astaxanthin and lipid content in the algae cells, providing a new approach for reducing greenhouse gas emissions and producing high-value products.