Photosynthetic accumulation of carbon storage compounds under CO2 enrichment by the thermophilic cyanobacterium Thermosynechococcus elongatus
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- Eberly, J.O. & Ely, R.L. J Ind Microbiol Biotechnol (2012) 39: 843. doi:10.1007/s10295-012-1092-2
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The growth characteristics of Thermosynechococcus elongatus on elevated CO2 were studied in a photobioreactor. Cultures were able to grow on up to 20% CO2. The maximum productivity and CO2 fixation rates were 0.09 ± 0.01 and 0.17 ± 0.01 mg ml−1 day−1, respectively, for cultures grown on 20% CO2. Three major carbon pools—lipids, polyhydroxybutyrates (PHBs), and glycogen—were measured. These carbon stores accounted for 50% of the total biomass carbon in cultures grown on atmospheric CO2 (no supplemental CO2), but only accounted for 30% of the total biomass carbon in cultures grown on 5–20% CO2. Lipid content was approximately 20% (w/w) under all experimental conditions, while PHB content reached 14.5% (w/w) in cultures grown on atmospheric CO2 and decreased to approximately 2.0% (w/w) at 5–20% CO2. Glycogen levels did not vary significantly and remained about 1.4% (w/w) under all test conditions. The maximum amount of CO2 sequestered over the course of the nine-day chemostat experiment was 1.15 g l−1 in cultures grown on 20% CO2.