Physiological responses to light intensity and photoperiod of the halotolerant cyanobacterium Desmonostoc salinum CCM-UFV059

The growth and physiology of Desmonostoc salinum CCM-UFV059 were analyzed regarding different light regimes and in presence of NaCl (100 mM). Similar growth patterns were observed regardless the treatments and cells under 70 μmol m−2·s−1 (16:8 h light/dark) displayed the highest growth rate. Biomass was higher (~1.60 g·L−1) under continuous light. Higher amounts of proteins were observed in 16:8-photoperiod. Cyanophycin and phycobiliproteins contents were lower under 70 μmol m−2·s−1 (16:8). Carbohydrates were invariant considering the same light intensity. Neutral lipids showed higher levels under 70 μmol m−2·s−1 (16:8). D. salinum also produced considerable amounts of biomass in medium with salt. Our results provide novel insights into how distinct light regimes interfere with the cyanobacterial metabolism. More importantly, the ability of CCM-UFV059 to sustain photosynthesis and to produce biomass under moderate saline conditions and long-day conditions highlights the possibility of its cultivation in brackish waters in different regions.