Streptomycin was isolated from which organism?

• A. Penicillium notatum
• B. Streptomyces griseus
• C. Streptococcus pyogenes
• D. Bacillus subtilis

Answer: (B)

Streptomycin is an antibiotic produced by a soil-dwelling bacterium of the genus Streptomyces, specifically Streptomyces griseus. This organism was found to synthesize streptomycin, which was isolated and developed in the 1940s and became famous as one of the first antibiotics effective against tuberculosis. The Streptomyces genus is well known for making many antibiotics, unlike the other organisms listed: Penicillium notatum is the producer of penicillin, Streptococcus pyogenes is a pathogenic bacterium, and Bacillus subtilis is a different bacterium that does not producer streptomycin.