Author(s): Muluneh Menamo and Zinabu Wolde
Many studies have addressed the effect of different environmental factors on growth, heterocyst frequency and N fixation of cyanobacteria. One of the factors is water quality. Different cyanobacteria strains different efficiency to adapt the quality of water. Therefore, this study was conducted to select the best combination of N-fixing cyan bacterial strains under different water sources. A factorial combination of the three Anabaena species strains (E10, E3 and E8) and two water sources (tap water and distilled water) were laid out in a complete randomized design in the laboratory set up. The ANOVA revealed that cyanobacteria strain E3 performed best on distilled than in tap water in terms of optical density, heterocyst frequency and total nitrogen than the other strains but no significant differences appeared between the two water sources. Thus, indicated that cyaobabacteria strains are growing in different water sources and the ability to grow more than one water sources.