Growth performance of several Spirulina strain analysis_Growth and pigment parameters analysis

Growth was monitored daily by measuring OD750 and Phycocyanin content (CpcC_{pc}Cpc) was quantified spectrophotometrically at 652 nm and 615 nm using a Shimadzu UV-1280 UV-VIS Spectrophotometer (Shimadzu Corporation, Kyoto, Japan).Measurements and Calculations:

Maximum Specific Growth Rate (μmax):

μmax = (log(N2) - log(N1)) / (t2 - t1)

Variables:

N2: OD750 at time t2.

N1: OD750 at time t1.

t2 and t1: Times within the exponential growth phase (in days).

Dry Weight (DW):

DW = 9.9040 * OD + 0.7440

Variables:

OD: Optical density at 750 nm (OD750).

Biomass Productivity (P):

P = (Xf - Xi) / (tf - ti)

Variables:

Xf: Final biomass dry weight (g/L).

Xi: Initial biomass dry weight (g/L).

tf and ti: Final and initial cultivation times (in days).

Phycocyanin Content (Cpc):

Cpc = (A615 - 0.474 * A652) / 5.34

Variables:

A615: Absorbance at 615 nm.

A652: Absorbance at 652 nm.

Phycocyanin Yield :

Ypc = (Cpc * VPBS) / DW

Variables:

Cpc: Phycocyanin content (mg/mL).

VPBS: Volume of phosphate buffer saline (mL).

DW: Total biomass dry weight (g).