Authors: Amit Kumar, Sharmin Rahman, Md. Naimul Hassan, K. M. Nazmul, Mst. Shekha Nasrin, Mahmudul Hasan Chowdhury, Rashiduzzaman Emran
Abstract: Soil bacteria are essential for maintaining soil fertility and ecosystem functioning; however, information on the culturable bacterial diversity of many Bangladeshi soil series remains limited. This study aimed to isolate, enumerate, and characterize culturable bacteria from the Kaunia and Jamun soil series of Bangladesh. Soil samples were collected from agricultural fields in Mithapukur, Rangpur, and bacterial isolates were obtained using serial dilution and spread plate techniques. Bacterial populations were quantified as colony-forming units (CFU), while colony morphology and staining characteristics were used for phenotypic characterization. Kaunia soil contained a slightly higher bacterial population (4.6 × 10⁸ CFU g⁻¹ soil) than Jamun soil (4.4 × 10⁸ CFU g⁻¹ soil). Nine and seven distinct bacterial colonies were isolated from Kaunia and Jamun soils, respectively. The isolates showed considerable variation in colony morphology and included both Gram-positive and Gram-negative bacteria, with several exhibiting spore- and capsule-forming abilities. These findings provide baseline information on the culturable bacterial diversity of the Kaunia and Jamun soil series and support future molecular and functional studies for sustainable agricultural applications.
Keywords: Soil bacteria; Kaunia soil series; Jamun soil series; Colony, morphology; Bacterial characterization.