Growth factors arrangement enhances Thermosynechococcus sp. CL-1 carotenoid productivity during CO₂ fixation

CO₂ bio-fixation by photosynthetic microorganisms not only offer high efficiency on its process, but also produce valuable byproducts. Carotenoids are one of the interesting byproducts of the photosynthetic microorganism cultivation due to its wide application in industries. Isolated cyanobacterium, Thermosynechococcus sp. CL-1 (TCL-1), was assessed for its theoretical feasibility of performance on biomass productivity, carotenoid (zeaxanthin, β-carotene) productivity and CO₂ fixation rate. The cultivation carried out under various growth factors including light intensity, concentration of nitrogen supply and salinity. Cultivation with the addition of 5.8 mM nitrogen supply under light intensity of 1000 μE/m²/s and 0.14 M salinity gained the best results on biomass productivity (90.3 mg/L/h) and CO₂ fixation rate (129.1 ± 5.5 mg/L/h) at the 8th hour of cultivation. This results related with the highest zeaxanthin productivity which reached 0.074 ± 0.004 mg/L/h and β-carotene productivity of 0.39 ± 0.03 mg/L/h. The results indicated that TCL-1 is the potential source to efficiently produce carotenoid compounds.