ISOLATION AND CHARACTERIZATION OF ANTIBIOTIC PRODUCING ACTINOMYCETES IN A RHIZOSPHERE ENVIRONMENT
abstract
This study used the crowded plate method, streak plate method, pour plate method, and standard microbiological method to isolate and characterize actinomycetes that produce antibiotics in rhizosphere environments. Testing procedures included gram staining, starch hydrolysis, casein hydrolysis, lipid hydrolysis, citrate, methyl red, catalase, and indole. Starch casein agar and Nutrient agar were used to characterize the growth organisms. The total number of colony forming units ranged from 3.9106 to 5.2106 after only 5 of the 13 isolates (from a total of 25 soil samples) showed visible growth and had antimicrobial activity on chosen organisms (Stapylococus aureus, Bacillus subtilis, and Escherichia coli). Four of the five isolates obtained from this work were from the the B, F, H, and M subgenera of Streptomycetes, and the other from the Nocardia subgenus (L). In contrast, isolates F, H, L, and M were active against Staphylococcus aureus with zones of inhibition measuring 8mm, 9mm, 16mm, and 9mm, respectively, while isolates B, F, H, L, and M were active against Bacillus subtitis with zones of inhibition measuring 5mm, 11mm, 11mm, 19mm, and 7mm, respectively. Isolate B was active against Escherichia coli with a zone of inhibition measuring 26mm According to this study, Streptomyces is the actinomycete that produces the most antibiotics in soil. Therefore, it is advised to only use antibiotics when necessary and to store them under proper conditions (temperature and pressure). Further purification, elucidation, and characterization are also advised in order to learn more. the effectiveness, novelty, and economic value of antibiotics.