Effects of the spatial and spectral distribution of red and blue light on Haematococcus pluvialis growth

The spatial and spectral distribution of light were essential for H. pluvialis growth and astaxanthin yield. In this work, experiments and numerical simulation with red and blue light in different ratios have been carried out on H. pluvialis. Although the light transmittance along the incident direction decreased significantly with increasing blue light ratio, the growth of H. pluvialis did not show linear relation with the absorption of blue light. Due to the red/blue light ratio of 2:1 matching the chlorophyll a/b ratio well, it produced the highest biomass and photosynthetic pigments, which were 19% and 62% higher than that under red light, respectively. The trend of maximal photochemical yield (Fv/Fm) and non-photochemical quenching (NPQ) change were similar to the content of chlorophyll and carotenoids separately. The highest carotenoids content and NPQ has been observed under red/blue light in the ratio of 2:1, which might bring H. pluvialis strong self-protection from high light and high astaxanthin yield.