In the flask cultures, the cell concentration of photosynthetic bacteria was
measured spectrophotometrically at a 660 nm wavelength. The dry-cell weight
(DCW) was determined by weighing the cell pellet after being dried in an oven at
105°C for 12 h. The cell pellet was prepared by centrifuging a 5 ml sample of
broth culture at 3500 rpm for 20 min and then by decanting the supernatant
after washing twice with distilled water. The number of viable cells was counted
using a hemocytometer under a light microscope immediately after the cells were
fixed with Lugol solution