Purple Nonsulfur Bacteria (PNSB) Isolated from Aquatic Sediments and Rice Paddy in Iligan City, Philippines

The purple nonsulfur bacteria (PNSB) are one of the most diverse photosynthetic bacteria. They are adaptable phototrophic organisms known to occur in water columns of rice fields, wastewater environments, aquatic sediments and in activated sludge systems. This research study aimed to isolate, identify, and characterize PNSB from aquatic sediments and rice fields in Iligan City. Isolation of the source of organisms was obtained through a Winogradsky’s column. After six weeks of incubation of the column, organisms were further incubated with the Acetate Yeast Extract Medium. Morphological characterization of the isolated PNSB showed Gram-negative, non-spore forming, thin, elongated rods. Cultural characterization showed orange colonies, an indication for the presence of carotenoids. The isolated PNSB utilized citrate, dextrose, and soluble starch as sole carbon sources. Initial identification of the isolated PNSB following evaluation with published articles and identification keys indicates that they belong to the genus Rhodopseudomonas.

 

Keywords: gram-negative, photosynthetic bacteria, phototrophic organism Rhodopseudomonas, Winogradsky’s Column.