Abstract

Sixteen soil samples were collected from different refuse dump sites in Minna, the capital Niger State, and analysed for the presence of Bacillus species. Physical-chemical analysis of the soil samples revealed the followings: PH value 6.89-8.47; moisture content 1.58 – 21.21% and temperature 27-28ºC. Using both pour plate and streak method of inoculation, total bacterial count in the soil samples ranged from 3.8×104 cfu/g 16.0×104 cfu/g. The identified Bacillus species included: Bacillus cereus (30.8%), Bacillus brevis (1.9%) Bacillus polymyxa (3.8%), Bacillus lichenifomis (13.5%), Bacillus spherericus (7.7%), Bacillus mycoides (13.5%), Bacillus pumilus (7.7%), Bacillus subtilis (3.8%), Bacillus alvei (1.9%), Bacillus laterosporous (1.9%), Bacillus firmus (9.6%) and Bacillus circulars (3.8%). Antibiotic production tests indicated that nine Bacillus species out of twelve isolated in this study could be used to produce antibiotics that had effect on the test organisms. However, Bacillus polymyxa, Bacillus sphaericus and Bacillus laterosporous had little or no effect on the tested organisms. This study suggests that some Bacillus species have potential to produce high quality antibiotics that can be use to control microbial growth in future.

Keywords

Antibiotics, Broad spectrum, Bacillus species, Narrow spectrum.