Isolation and Characterization of Antibacterial Bacillus species from Soil Samples in Southern Algeria

Abstract

Aiming to find a Bacillus capable to inhibit standard pathogenic bacteria growth, search has been conducted in Southern Algeria. The oldest Algerian Ksar soils could be a precious resource of both bacillus taxa and bioactive compounds. A 2000 soil, distributed at a rate of 50g, was sampled from various places (east, west, north and south directions) in the Ksar site. Isolation media nutrient agar (GN) and tryptic soy agar (TSA) were inoculated by spreading tablecloth by 01 ml of dilution previously prepared. Their antibacterial activity against four pathogenic bacteria was evaluated according to two stages consisting of a primary and secondary screening. A phenotypic and biochemical characterization was carried out for the isolates selected according to their antibacterial power. Soils samples thereof led to the recovery of 44 diverse bacillus strains. Seven bacillus strains amid the 44 recovered were selected for their antibacterial properties. Tests indicated that Bacillus (BP2) and Bacillus (BP4) strains showed the two widest inhibition zones against Salmonella typhi with a diameter of 35 and 25 mm respectively. Against Escherichia coli the former (BP2) exhibited a 22 mm inhibition zone. Thus, the current study based on Algeria South soils samples seems promising for discovery of new bacillus strain and novel bioactive substances.