Articles

Extraction and Native PAGE Separation of Phycobiliproteins from Some Cyanobacteria Collected from Their Natural Habitats

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Phycobiliproteins are a group of coloured proteins present in cyanobacteria and algae. They can be divided into three types based on their absorption spectra. These are phycocyanin, phycoerythrin and allophycocyanin. These pigment proteins are used as potential natural colorant in chewing gums, candies, soft drinks, dairy products and cosmetics like lipstick and eyeliners. They are also extensively commercialized for fluorescent applications in clinical immunological analysis. The phycobiliproteins from cyanobacteria have also been reported to have ant-cancerous, anti-inflammatory and antioxidant properties. In view of the increasing demand of these fluorescent pigments, it becomes important to find new species of cyanobacteria and exploit them for their phycobiliprotein content. In present work some commonly available cyanobacteria were collected from their natural habitats and analysed for their phycobiliprotein content. The extraction of phycobiliprotein was done in phosphate buffer and quantitative analysis of the pigment components was done. The study showed that all the cyanobacteria are the potential source of phycocyanin whereas phycoerythrin is significantly present in species of Lyngbya and Oscillatoria. The phycobiliprotein components were separated on Native PAGE which can be partially purified by electroelution. The percentage loss of phycobiliprotein content in stored cyanobacterial biomass for two months showed that phycoerythrin was more stable in Lyngbya and Oscillatoria as compared to the phycocyanin. The species of Scytonema showed good amount of phycocyanin content whereas allophycocyanin was significantly present and was stable in Aulosira sp.

Cyanobacteria: Isolation, Purification and Principles

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The primary means of nutrient uptake for cyanobacteria is oxygen-producing photosynthesis. Their ecological variety is astounding; they occupy a very wide range of lighted ecological niches in terrestrial, marine, and freshwater habitats. Despite this apparent metabolic consistency, they exhibit tremendous phylogenetic diversity. The fact that cyanobacteria have certain physiological and metabolic traits that are exclusively seen in prokaryotes significantly broadens this spectrum. The capacity to fix nitrogen in an aerobic manner under light is a special characteristic. Apart from Gonotheca species, all aerobic, nitrogen-fixing cyanobacteria—a structurally diverse group—produce heterocyst, the highly specialised cells that allow them to fix nitrogen efficiently in a fully aerobic environment by preventing the oxygen-sensitive enzyme nitrogenase from being inactivated quickly in vivo (Hazelton, 1978; Stanier and Cohen-Bazire, 1978; Stewart, Haystead, and Pearson, 1969). The same quantities of cyanobacteria could be isolated from freshwater using a technique using nutrient-saturated glass fibre filters, but the quantity of accompanying heterotrophic bacteria was reduced by 2- to 15-fold. a broad-spectrum antibiotic called imipenem. In comparison to some other Plactam antibiotics, the B-lactam antibiotic that inhibits peptidoglycan biosynthesis, was more effective at lowering the levels of heterotrophic bacterial contaminants associated with newly isolated cyanobacteria to a point that made it easier to grow axenic cyanobacterial cultures.