**3.3 Determination of pigments content: chlorophyll** *a***, carotenoids and phycocyanin**

The dosage of photosynthetic pigments of each microalgal species was carried out after extraction in 90% acetone. The concentration of Chlorophyll *a* was calculated according to the equation of Speziale, Schreiner, Giammatteo and Schindler [34] for the cyanobacterium and conforming to the equations of Jeffrey and Humphrey [35] for Chlorophyceae and the diatom.

Equation of Jeffrey and Humphrey [36] for Chlorophyceae:

$$\text{Chl}\,a\left(\mu\text{g}\,\text{l}^{-1}\right) = \mathbf{1}\,\mathbf{1}.\text{\textbf{93OD}}\_{664\text{nm}}\,\text{-}\mathbf{1}.\text{\textbf{93OD}}\_{647\text{nm}}$$

Equation of Jeffrey and Humphrey [35] for Diatom

$$\text{Chl}\,a\left(\mu\text{g}\,\text{l}^{-1}\right) = \mathbf{1}\,\mathbf{1}.4\mathsf{7}\mathsf{OD}\_{664\text{nm}}\,\text{-}\,\mathbf{0}.4\mathsf{OD}\,\mathbf{D}\_{630\text{nm}}$$

Carotenoid concentrations were calculated according to the equation of Chamovitz, Sandmann and Hirschberg [36] for cyanobacterium and according to Salguero et al. [37] for Chlorophyceae.

Cyanobacteria carotenoid (μg l−1) = (OD461nm − 0.046OD664nm) × 4

Chlorophyceae Carotenoid (μg l−1) = 0.0045 (3000OD470nm − 1.63OD750nmChl *a*). The phycocyanin (C-PC) pigment was isolated from *P. versicolor* using the method developed by Silveira et al. [38] With light modification. The C-PC contents were

quantified according the following equation:

$$\text{C}-\text{PC} \left( \text{mg } \text{ml}^{-1} \right) = \left( \text{OD}\_{615\text{nm}} - \text{0.474\text{OD}}\_{652\text{nm}} \right) / \text{5.43}$$

*The Solar Saltern of Sfax: Diversity of Hyperhalophilic Microalgae Species as a Promising... DOI: http://dx.doi.org/10.5772/intechopen.104712*
