Determination of chlorophyll and phycocyanin
Chlorophyll-a (Chl-a) was measured using a standard methanol-based methodology (Marsac and Houmard, 1988).
PC extraction and quantification was carried out using repeated freeze-thaw cycles based on Yoshikawa and Belay (2008). Briefly, this method extracts PC from fresh biomass using a repeated freeze-thaw and soaking regime and then quantifies PC spectro-photometrically based on absorbance at three wavelengths: 620 nm, 650 nm and 680 nm. PC content is calculated following the Yoshikawa equation, where cPC is C-phycocyanin and aPC is allophycocyanin:
cPC, mg/mL = 0.162 × OD620 – 0.098 × OD650 (1)
aPC, mg/mL = 0.180 × OD650 – 0.042 × OD620 (2)