Spectrophotometric Quantification of C-Phycocyanin

The dried biomass (1 g) was homogenized with 0.1 M sodium phosphate buffer (pH 7) and repeated freezing (at −20°C for 3 h) and thawing (at 4°C for 5 min) were done in dark. Subsequently, the mixture was centrifuged at 10,000g and 4°C for 20 min to separate clear supernatant that contains phycobiliproteins [44 ]. A supernatant sample was run on 12.5% SDS-PAGE. The absorbance of supernatant samples was evaluated at wavelengths 600, 610, 615, 620, 630, 640, 650, and 652 nm (OPTIZEN Scan UV/VIS spectrophotometer, KLab Co., Daejeon, Republic of Korea) for C-phycocyanin.
The concentration of C-phycocyanin was calculated as previously reported by Siegelman and Kycia [45 ] as follows: $\begin{array}{c}C-\mathrm{p}\mathrm{h}\mathrm{y}\mathrm{c}\mathrm{o}\mathrm{c}\mathrm{y}\mathrm{a}\mathrm{n}\mathrm{i}\mathrm{n}=\frac{\left(A_{615}–0.474\times A_{652}\right)}{5.34}\text{,}\end{array}$ where A₆₁₅ is the absorbance measured at 615 nm and A₆₅₂ is the absorbance measured at 652 nm.