Abstract

The aim of the study was to evaluate antifungal and antibacterial properties of surfactin isolated from Bacillus subtilis growing on molasses. Molasses replaced the traditional microbiological media to culture the B. subtilis. 10 phytopathogens and 30 E. coli strains were used in the study. The results demonstrated the ability of surfactin produced byBacillus sp. growing on molasses to inhibit mycelial growth of the 4 fungi from 10 tested and all E. coli strains measured by agar plate inhibition assays. Fungi inhibited to the greatest degree as measured by the inhibition zones were Botrytis cinerea A 258 (~50% of inhibition), Sclerotinia sclerotiorum K 2291 (~50% of inhibition), Colletotrichum gloeosporioides A 259 (~40% of inhibition), Phoma complanata A 233 (~38% of inhibition),Phoma exigua var. exigua A 175 (~20% of inhibition). Among the E. coli, high inhibition growth was noted in 76% of the isolates. Application of natural products such as biosurfactant may be a new approach to biological control therefore reducing the need for synthetic chemical compounds.

Key words: Phytopathogens, Escherichia coli, Bacillus subtilis, surfactin, biocontrol, phytopathogens, biosurfactant.