Diatoms (Bacillariophyceae) are important to primary productivity of aquatic ecosystems.
This algal group is also a valuable source of high value compounds that are utilised
as aquaculture feed. The productivity of diatoms is strongly driven by light and CO2
availability, and macro- and micronutrient concentrations. The light dependency of
biomass productivity and metabolite composition is well researched in diatoms, but
information on the impact of light quality, particularly the productivity return on
energy invested when using different monochromatic light sources, remains scarce.
In this work, the productivity return on energy invested of improving growth rate,
photosynthetic activity, and metabolite productivity of the diatom Chaetoceros muelleri
under defined wavelengths (blue, red, and green) as well as while light is analysed.
By adjusting the different light qualities to equal photosynthetically utilisable
radiation, it was found that the growth rate and photosynthetic oxygen evolution was
unchanged under white, blue, and green light, but it was lower under red light. Blue
light improved the productivity return on energy invested for biomass, total protein,
total lipid, total carbohydrate, and in fatty acids production, which would suggest
that blue light should be used for aquaculture feed production.
