The algae biomass concentration was determined by a correlation
between the absorbance at 540 nm using a Shimadzu
UV-1750 spectrophotometer and dry weight of biomass (biomass
concentration (g/L) = 0.3654 OD540nm + 0.0703, R2 = 0.993). This
calibration curve was obtained from the dry biomass weight determined
by weighing the cells after washing for 2 times with distilled
water followed by drying in an 80 C oven overnight until a
constant weight was achieved. The specific growth rate was calculated
as the following equation: