Optimizing photon dose and frequency to enhance lipid productivity of thermophilic algae for biofuel production

The aim of this work was to examine the potential of the thermophilic green microalga Micractinium sp. to accumulate triacylglycerols (TAGs) and to develop a light strategy to increase TAG productivity in this alga. To this end, dense cultures of Micractinium sp. were grown at 37 °C under nitrogen (N) starvation and exposed to a light intensity of 1000 µmol photons m−2 s−1 of different light regimes. The highest per-biomass TAG-content and maximal volumetric productivities of TAG were displayed by the cultures grown under flashing light of 5 Hz with 50% duty cycle. Based on the results, a sufficiently high-starting culture density should be combined with a high irradiance delivered by an appropriate light regime to enhance the production of biomass enriched TAGs.