ISOLATION AND CHARACTERIZATION OF SOIL-BORNE UREASE PRODUCING BACTERIA

Dr. Anyadoh-Nwadike S. O.*, Ezeanyika C. and Okorondu S. I.

ABSTRACT

Urease producing bacteria are significant for their increasing roles in human pathogenicity, biocementation and as soil fertilizer. This study was therefore aimed at isolation of such urease producers from urea-rich soil samples collected from various locations in Federal University of Technology Owerri. Sample collection and processing were done using standard microbiological methods. Soil samples were aseptically collected from seven different locations. Isolation of the various bacterial species was done using Nutrient, MacConkey, Eosin Methylene Blue and Salmonella Shigella agar. Identification of isolates was done using morphological characteristics as well as standard microbiological and biochemical procedures. The urease producing strains of bacteria were obtained using the urease hydrolysis test. Urease tolerance level was obtained using the optical density on a spectrophotometer. Results revealed the presence of twenty one bacterial strains of seven species; Baccilus sp, Staphylococcus aureus, Shigella sp, Escherichia coli, Proteus sp, Klebsella sp and Enterobacter sp. Four of the isolates designated as C1, F2, C2, and D1 were selected on the basis of qualitative and quantitative screening analysis for urease activity. Isolate C1 was identified as Proteus sp., C2 was identified as Klebsiella sp. Isolate D1 was also identified as Proteus sp. while F2 was also identified as Klebsiella sp. Urease tolerance test revealed D1 (Proteus sp) having higher growth rate of 0.063 at a urea concentration of 1M with the growth rate decreasing as urea concentration increased. Isolate C2 (Klebsiella sp) also showed high growth rate of 0.042 at a urea concentration of 1M. Growth rate decreased with increasing urea concentration. These organisms with high urease tolerance level can be used for diverse purposes ranging from enzyme production, medical uses to calcite precipitation in biocementation.

Keywords: Urease, Bacteria, Soil, Urea-rich, Biocementation.