Optimisation of Culture Conditions for Porphyridium purpureum and Characterisation of Algal Biomass for Value Added Products.

Porphyridium spp. is a red micro alga and is gaining importance as a source of
valuable products viz., phycobiliproteins (PB) especially red coloured phycoerythrin,
sulphated exopolysaccharides, and polyunsaturated fatty acids with potential applications in
the food and pharmaceutical industries. In the present study, the nutritional stress and CO2
supplementation were studied for enhancement of lipid content, PUFA especially EPA
content and biomass concentration. A two phase cultivation protocol where the Porphyridium
purpureum was first grown in growth enhancing Modified Medium for two weeks followed
by two week incubation in highly saline Artificial Sea Water medium was found to enhance
the lipid content to 18% with an EPA content of 19% and biomass concentration was 0.97g/L
compared. The other major fatty acids observed were Palmitic, oleic and arachidonic acid.
Supplementation with 5% CO2 was found to be growth enhancing with a significantly
enhanced EPA content to 25%. Water, sodium phosphate buffer and acetic acid–sodium
acetate buffer were used a extraction medium for phycoerythrin and purity of phycoerythrin
was found to be more in water (0.9%) than acetic acid buffer (0.7%) and sodium phosphate
buffer (0.79%). Phycoerythrin content was double in the culture grown on Modified medium
as compared to the culture grown in Artificial Sea water medium. Protein content of crude
phycoerythrin extract was 28.9%. Characterization of phycoerythrin was done by SDSPAGE.
The antioxidant property of phycoerythrin was carried out and it was observed that
the total antioxidant activity in water extract was more compared to acetic acid-sodium
acetate buffer. Reducing power assay showed an increase in reducing activity with increase
in concentration which indicates good reducing capacity.