Bacterial population and characterization of Sonatala and Bajoa soil series of Bangladesh

Being single celled, ancient life form, omnipresent and living in all conditions, bacterial population and characterization from different resources are very much important for its classification and identification. In soils the bacteria are to account for almost all the biological and chemical changes in environments. To determine bacterial population with characterization soil samples from two soil series, Sonatala and Bajoa, were collected. The bacterial population was counted by colony count method where 5.4×107 CFU/g soil in Sonatala soil and 7.7×107 CFU/g soil in Bajoa soil were available. Moreover, with intensive care not only colony characteristics but morphological characteristics were studied. Size, pigmentation, form, margin and elevation of well-isolated colonies of nutrient agar plates were observed. Shape and arrangement were determined from simple and negative stain. For determination of staining characteristics Gram stain, capsule stain, spore stain and acid fast stain methods were followed. Most of the bacteria of these soils were found as rod shaped. Gram- positive as well as spore forming bacteria were prominent where Gram-negative, non-spore forming, capsulated, non- capsulated, acid fast and non-acid fast bacteria were found.