What this work is about, in plain words
What share of the carbon absorbed by a culture stays in the biomass? The authors put the terminology in order and estimated this figure for the diatom Cylindrotheca closterium.
Microalgae build their biomass from the carbon they absorb during photosynthesis. The larger the share of absorbed carbon a culture fixes in its cells, the more economical its cultivation. However, different researchers calculate this figure differently, which makes it hard to compare species. The authors had two aims: to put the terms in order and to estimate the carbon fixation efficiency of the diatom Cylindrotheca closterium.
The culture was grown in the laboratory as a batch, on a nutrient medium, at constant temperature with air bubbling. The share of carbon in dry biomass was determined by elemental analysis.
According to the authors, carbon made up 23 % of dry biomass, and up to 90 % of the carbon absorbed by the culture was fixed in the biomass. Maximum productivity reached 1.25 g of dry weight per liter per day. The authors suggest that the high productivity of this species is explained precisely by efficient carbon fixation and a relatively small share of carbon in the biomass.
The work provides a common language for comparing cultures by how they use carbon, and an example calculation for one of the promising diatoms.
Limitations. The calculation was made for one laboratory culture grown as a batch. The authors offer their explanation of the high productivity as a hypothesis.