Isolation of antifungal bacteria from soil samples

Six strains of Bacillus cereus exhibiting antifungal activity were isolated from local environment and optimized for growth conditions. The isolates appeared neutrophiles, grew best at aeration and were represented by thermophiles and mesophiles. Growth inhibition zones of varying diameters were observed when the isolates were tested against Saccharomyces cerevisiae on nutrient agar. Largest inhibition zone measuring up to 16.25mm was observed for B. cereus Sn-21a after 48-72 hours of inoculation. Four of the isolates designated as Sn-18a, Sn-19a, Sn-20a and Sn-21a also showed antifungal activity against Candida albicans. For this test organism maximum growth inhibition zone (31mm) was noticed around filter paper disc loaded with 4X cell free cultural fluid of Bacillus cereus Sn-20a. The isolates Sn-20a and Sn-21a appeared thermophilic. Further work on these bacterial isolates is likely to define their antimycotic mode of actions and limitations regarding therapeutic applications of their antifungal exoproducts.