Isolation and Characterization Of Biodegrading Bacteria In Lubigi Wetland, Kampala

Abstract

Research was conducted to find out bacteria with potential for efficient urban organic waste degradation. Lubigi wetland was considered as the study area, because it witnesses inappropriate waste discharge with improper treatment, therefore a typical example for collection and isolation of natural bacteria degrading organic wastes. The objectives of the study were to: a) identify the different organic waste types present at discharge sites; b) obtain free-living bacteria degrading organic wastes; and c) characterize the isolates and study their degradation of organic matter. Three water and two soil samples from organic waste discharge sites were randomly selected from Lubigi wetland. The wetland is surrounded by densely populated Kampala’s slums of Kyebando, Kalerwe, Kanyanya, Bwaise, Kawaala, Namungoona, Nansana and Busega, the sources of urban organic wastes. The five samples collected were for isolating the bacteria that effectively degrade organic. Physico-chemical conditions were also considered and ideal conditions for the growth and culture of bacteria noted. Ideal temperature and pH was 25-37°C and 7-8, respectively. Ten pure isolates named P1 to P10 cultured on Nutrient Agar were used for bacteria culture, and characterization of the isolates was by visual observation of colonies and microscopic observation for endospores. Further, Gram staining tests, and biochemical tests were undertaken. Following the tests, the identified bacteria were Bacillus spp, Clostridium spp, Staphylococcus spp, Micrococcus spp, Streptococcus spp and Alcaligenes spp. Meanwhile, degradability of wastes through hydrolysis tests were performed to select the most effective bacteria strains. The highest decomposition activity in terms of percentage of positive hydrolysis tests was shown in pure isolates of Bacillus spp. From the research, it can be concluded that useful bacteria might be isolated from the surrounding environment for friendly bioconversion of organic wastes. However, the genetic makeup of bacteria strains is a crucial attribute for their selection and manipulation for improved degradation results.