Identification and partial characterization of antifungal and antibacterial activities of two Bacillus sp. strains isolated from salt soil in Tunisia

Abstract

Two Bacillus sp. strains (B29 and B27) isolated from soil in the South of Tunisia were tested for their
abilities to produce antimicrobial compounds. Both strains showed antimicrobial activity against Grampositive and Gram-negative bacteria, yeasts and fungi. The produced compounds were extracted by
using four different solvents. The hexane extract allowed to obtain maximum of activity of the strain B29.
The activity of the strain B27 was not elucidated by the four solvents used. Bio-autography results of B29
hexane extract revealed presence of different antibiotics and antifungal compounds with different Rf
values of 0.3 and 0.76 for antifungal compounds and of 0.12, 0.14, 0.19 and 0.3 for antibiotics. Two
active fractions were isolated from the culture broth of the strain B29 using semi-preparative HPLC.
Partial sequencing of the 16S RDNA gene was used to identify both of Bacillus strains. They may be
assigned to new Bacillus species.