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).