Screening for Antimicrobial and Enzymatic Activities of Bacillus and Pseudomonas Strains Isolated from Volcanic Soil of Tahart (Ahaggar, Algeria)

Abstract The soil represents a very important microbial niche, housing bacteria that can be a real source of biomolecules of interest. Indeed, this article represents a first bio-prospective study of a volcanic soil from the Tahart region (Tamanrasset, Algeria) which aims to research and characterize bacteria of the genus Bacillus and Pseudomonas producing enzymes and inhibitory substances. Diverse selective culture mediums were actually used to isolate Pseudomonas and Bacillus strains. These latters were phenotypically and an enzymatically characterized. The antibacterial characteristics of the pure culture, the supernatant, and the organic extracts were all investigated. The results showed that 60% of the bacteria from the genus Bacillus and Pseudomonas showed antimicrobial activity in vitro. On the other hand, our experimental results have revealed that the supernatant activity is slightly higher than that of pure culture and ethyl acetate showed a better extraction efficiency than chloroform and inhibitory zones, which vary between 7 and 25 mm in diameter. Moreover, the Bacillus antagonists represent 45% (B. thuringenis, B. sphericus, B. cereus, B. thiaminolyticus, B. anthracis and B. subtilis), followed by 32% of Pseudomonas bacteria (P. aeroginosa, P. luteola, P. flurescens). In conclusion, despite the acidity of the soil substrate, an interesting strains of bacteria producing inhibitory substances with enzymatic potential were selected.