Maximising phycocyanin extraction from a newly identified Egyptian cyanobacteria strain: Anabaena oryzae SOS13.
A potentially promising Egyptian cyanobacterial isolate (Anabaena oryzae) was identified by morphological, biochemical approaches as well as sequencing a fragment of the 16S rDNA gene as new strain denoted as Anabaena oryzae SOS13. The new strain was used to produce phycocyanin through extraction using a physical (freeze-thaw) or an enzymatic (lysozyme) approach. Combined freezing-thawing treatments were associated with different levels of phycocyanin yield, where the combination -50oC x 25oC achieved complete extraction of the three pigments (100% each). The enzymatic extraction of the three pigments was significantly influenced by the temperature giving maximum yields at 40oC but was much less effective than the physical freeze-thaw method that is more economic and less liable to potential chemical changes. The resulting extract could be easily purified by the two step ammonium sulfate fractionation giving a product with two SDS-PAGE bands (>15 kD and <25 kD).