Photosynthesis and pigment production: elucidation of the interactive effects of nutrients and light on Chlamydomonas reinhardtii

Chlamydomonas reinhardtii produces a variety of compounds that can be beneficial to human and animal health. Among these compounds, application of photosynthetic pigments, such as chlorophylls and carotenoids, has gained considerable interest in numerous industries. A better understanding on the interactive effects of essential nutrients and light on microalgal physiology and pigment production would be beneficial in improving cultivation strategies. Therefore, this study evaluated biomass, carotenoid and chlorophyll yield and the following fluorescence parameters: quantum yield in PS II [Y(II)] and electron transport rate (ETR) using response surface methodology (RSM). The F-v/F-m, Y(NO) and Y(NPQ) were also monitored; however, no significant relationship was observed. From the investigation it was apparent that nitrogen and carbon; as well as the interactive effects of (nitrogen and carbon) and (carbon and light irradiance) were significant factors. The model predicted the optimum conditions for maximum carotenoids (8.15 +/- 0.389 mg g(-1)) were 08.7 mol l(-1) of nitrogen, 0.2 mol l(-1) and 50 mu mol photon m(-2) s(-1) of light irradiance. While maximum chlorophyll (33.6 +/- 0.854 mg g(-1)) required a higher nitrogen (11.21 mol l(-1)). The photosynthetic parameters [Y(II), ETR] was correlated with the primary pigments and biomass production. Increased photosynthetic activity was associated with high carbon and light. The Y(II)and ETR of PSII under these conditions were 0.2 and similar to 14, respectively. This approach was accurate in developing the model, optimizing factors and analysing interaction effects. This study served to provide a better understanding on the interactions between factors influencing pigment biosynthesis and photosynthetic performance of Chlamydomonas reinhardtii.

Automated summary

This study evaluated the physiological and pigment production of Chlamydomonas reinhardtii using response surface methodology. It found that nitrogen, carbon, and light irradiance significantly affected the biomass, carotenoid, and chlorophyll yield. Increased photosynthetic activity was associated with high levels of carbon and light.