Isolation, optimization and characterization of selected Cyanophycean members

Abstract

Ten spp. of Cyanobacteria (non-heterocytous) were isolated from various marine habitats. Three bioactive potential forms, were observed for their optimization of growth, subjecting them to various concentrations of NaCl, <i>p</i>H, light and nutrients. Proteins, lipids, and carbohydrates were also evaluated from some of the forms. Exponential growth rates of (0.062 and 0.01 g day^-1) were exihibited by<i> Phormidium tenue</i> and <i>S</i>.<i> cedrorum, </i>respectively, in the first two weeks. Wide range (0-100%) of salinity tolerance was noticed in <i>Phormidium tenue</i>, <i>S. cedrorum</i> and <i>S</i>.<i> pevalekii</i>. Optimum growth and maximum biomass were obtained in media with NaCl concentrations of 5-25%. All three species exhibited maximum growth in media with <i>p</i>H 7.5, and responded well with increasing concentrations of NO₃-N. The quantum of nitrate required for maximum growth varied with species. <i>Synechococcus cedrorum</i> produced higher biomass in the artificial light, compared to the same in direct sunlight, and diffused light. <i>Spirulina major </i>showed maximum (66.72%) proteins, while <i>Oscillatoria </i>sp<i>.</i> was rich (28.82%) in<i> </i>carbohydrate contents. <i>Phormidium</i> showed relatively higher (11.3%) lipid contents.