IJLST 2016 Volume 9 Issue 7
International Journal of Life Sciences and Technology (IJLST) ISSN: 0974-5335
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Effect of pH on Freshwater Cyanobacteria Isolated from Different Habitats of Southern Karnataka. Sharath Chandra K. and M. Rajashekhar. IJLST (2016), 9(7):56-64
Effect of pH on Freshwater Cyanobacteria Isolated from Different Habitats of Southern Karnataka
Authors & Affiliation:
Sharath Chandra K. and M. Rajashekhar
Department of Studies in Biosciences, Mangalore University, Mangalagangothri- 574 199, Karnataka, India.
In the present study, the influence of pH on the growth of six species of cyanobacteria has been carried out. Among physical factors pH is a very important factor which influences their occurrence and diversity. By this study it was also found that Microcystis aeruginosa (bloom forming cyanobacteria) which showed growth at highly alkaline pH (9.0 to 10.0). Phormidium chlorinum (isolated from sewage water) was able to grow at acidic pH (5.0 to 6.5). But overall study showed that neutral to slightly alkaline pH (7.0 to 8.5) is the optimum range for good growth of most of the cultured species. It was also revealed that species Geitlerinema calcuttense of dairy effluents showed good growth at acidic to alkaline pH. Scytonema bohnerii isolated from a sulfur spring prefer to grow at slightly acidic pH (6.5). The overall study showed cyanobacteria generally prefer neutral to alkaline pH for their optimum growth. It was found that, cyanobacteria under acidic to neutral pH (5.5 to 7.0) can synthesize higher carotenoids rather than under alkaline pH. The study indicated that, they can produce higher phycobillin pigments in terms of phycocyanin, allo- phycocyanin and phycoerythrin at slightly alkaline pH (8.0 to 8.5). The study also revealed that cyanobacteria produce higher phycoerythrin pigment at slight alkaline pH between 7.5 and 8.0 except the species, Microcystis aeruginosa where it showed higher phycoerythrin content at pH 9.0. The overall study revealed that as the pH value increased, there was an increase in the phycobilin pigments in the cyanobacteria.
Key words: Freshwater, Cyanobacteria, pH, Biomass, Pigments, Southern Karnataka.