Preliminary study on the ability of a streptomyces specie isolated from garden soil to produce antimicrobial agent

Great limitations of some antibiotics nowadays range from human and animal toxicity to narrow spectrum of efficacy. Most synthetic antibiotics have failed to satisfy the needs of their production. There is need therefore to isolate new strains of microorganisms that can yield more effective drugs to be used in tackling the erupting microbial infections. A strain of actinomycete was isolated from a garden soil. The strain grows at optimal temperature of 30oC and maximum temperature of 42oC in a slightly alkaline medium of pH 6.8 and was identified as a Streptomyces sp. Horikoshi JAS medium supported the highest growth and highest production of the antibiotic. Antimicrobial activity of the organism as well as its extracted and purified metabolite was tested against some microorganisms namely Bacillus sp, Candida sp, Aspergillus sp, Staphylococcus aureus, Pseudomonas sp and Streptococcus sp. Both the isolate and its metabolite showed a reasonable activity against all the test organisms except Streptococcus sp. Antibiotic accumulation in broth started 24hrs after incubation and increased, reaching maximum at 72 hrs and stationary phase during production was observed at 96 hrs. Maximum pH for good yield was 3-5 with low yield at pH 6. Further research on the organism and its metabolite are still in progress to enable the production and further testing of the novel antibiotic.