Optimisation of the biomass measurement of pigmented microorganisms - Case study of the Rhodomonas Salina

Léo Langot, Tafadzwa Lucky Maphosa, Solène Foe Ayida & Daniel Ellehammer Larsen

Studenteropgave: Semesterprojekt


In order to relieve some of the pressure on the world's fish stocks caused by overfishing on certain species, a research group is exploring the possibilities in growing copepods on an industrial scale. To do this a large scale growth of microalgae is required, a process that demands a high level of monitoring. A critical aspect of the monitoring, is keeping the biomass under control, for this the optical density measurement is often used, as a way of monitoring the growth of microorganisms and assessing their biomass. However, there is a distortion between this biomass assessment, and the actual biomass. The pigments in the algae are considered one of the key factors contributing to this distortion. Our goal is to quantify the growth of the algae under certain conditions, and quantify the corresponding chlorophyll contents. This data will be collocated with the cell count found from an analysis of the OD at three wavelengths, and the actual cell count, found with a Coulter counter. It was found that the optimal wavelength for monitoring the growth of this specific alga was 750 nm when grown in a medium with optimal nitrogen contents and under a high light exposure. However the results of the conducted pigment extractions was inconclusive in order to provide a valid argument about the influence of pigments on the OD.

UddannelserMiljøbiologi, (Bachelor/kandidatuddannelse) Bachelor el. kandidat
Udgivelsesdato9 jan. 2016
VejledereSøren Laurentius Nielsen


  • Coulter counter
  • Optical
  • Pigmented
  • Distortion
  • Microalgae
  • Biomass
  • Density
  • Multicultivator
  • Microorganisms
  • Salina
  • OD
  • Phycoerythrin
  • Rhodomonas
  • Calculation