Growth optimisation of Chlamydomonas nivalis and a wild microalgae consortium with respect to CO2, light and temperature
Résumé
Domestication of microalgae is a necessary step towards the use of microalgae as all-year round crops. This process requires selection; study and adaption of wild strains to specific conditions. Microalgae cultivation in greenhouses could be possible by both increasing carbon biofixation and biomass productivity1. An isolated consortium microalga from North West Europe (NWE) and a pure strain of Chlamydomonas nivalis were studied within the project of INTERREG IDEA-NWE, because of their tolerance to low temperatures and light intensities. Statistical Factorial Experimental Design 23 was applied, with three independent variables. Experiments were carried out at small laboratory scale for studying the effect of different light intensities (20 - 200 µmol/m2s), CO2 concentrations (0,04 - 5 %) and temperatures (5-25 ºC) on their growth performances. Based on biomass production, C. nivalis best growth conditions were 5 ºC, 20 µmol/m2s and 5 % of CO2 resulting in a cell concentration and productivity of 0,68 g/l and 0,49 g/ld, respectively. Best conditions of growth of mixed culture were 25 ºC, 20 µmol/m2s and 5 % of CO2, giving 0,46 g/l of biomass and a productivity of 0,33 g/ld. The single and mixed culture showed influence by maximum CO2 concentration and less influence by light intensity and temperature in the range tested within this study, which suggested that these strains are robust and could grow under greenhouse conditions in NWEurope with minimal heating and artificial lighting.