Nitrogen and 17β-Estradiol level regulate Thermosynechococcus sp. CL-1 carbon dioxide fixation, monosaccharide production, and estrogen degradation.

Thermosynechococcus sp. CL-1 (TCL-1), a thermophilic cyanobacterium from a hot spring in Taiwan, has been known of its efficiency in CO fixation, byproducts production (pigments, macromolecules). This study observed the performance of TCL-1 in CO fixation, estrogen degradation, and monosaccharide production under various levels of Dissolved Inorganic Nitrogen (DIN) and 17β-estradiol (E2) as nitrogen supply and estrogen addition. Under nitrogen starvation, TCL-1 performed similar results on CO fixation rate and biomass production but enhanced the monosaccharide production compared to the cases of high nitrogen supply. The highest CO fixation rate and glucose productivity reached to 151.8 ± 6.6 and 38.1 ± 0.9 mg/L/h, under DIN level of 0.58 mM and 0.5 mg/L E2. Adding E2 in the system did not inhibit the performance of TCL-1. During the cultivation, TCL-1 converted E2 into E1 and the biodegradation was the main path for estrogen degradation. Total E2 degradation reached to 69.4 ± 2.0%.