Question

Which group of microbes is known for its role in the production of antibiotics?

• A. Actinomycetes
• B. Cyanobacteria
• C. Archaea
• D. Yeasts

Hint:

• Actinomycetes, particularly the genus \textit{Streptomyces}, are a primary source of antibiotics used in medicine.
• They are filamentous bacteria found abundantly in soil.
• Examples of antibiotics from Actinomycetes: streptomycin, tetracycline, erythromycin.
• Fungi (e.g., \textit{Penicillium}) are also important antibiotic producers.

Answer 1

The Correct Option is A

Antibiotics are antimicrobial substances active against bacteria. Many microorganisms produce antibiotics, likely as a competitive mechanism in their natural environments.

• Actinomycetes: This group of Gram-positive bacteria, characterized by their filamentous (mold-like) growth, is the most prolific source of clinically useful antibiotics. The genus Streptomyces within the Actinomycetes is particularly renowned, producing over two-thirds of naturally derived antibiotics, including streptomycin, tetracyclines, erythromycin, neomycin, chloramphenicol, and many others.
• Other Bacteria: Some other non-filamentous bacteria (e.g., Bacillus species, which produce bacitracin and polymyxin) also produce antibiotics.
• Fungi: Certain fungi are also famous antibiotic producers, notably Penicillium species (source of penicillin) and Cephalosporium (now Acremonium) species (source of cephalosporins).
• Cyanobacteria (option b) produce a variety of bioactive compounds, some with antimicrobial properties, but they are not as prominent as Actinomycetes for clinically used antibiotics.
• Archaea (option c) are known to produce some antimicrobial compounds, but their contribution to clinically used antibiotics is currently less significant compared to bacteria and fungi.
• Yeasts (option d), which are unicellular fungi, are not major producers of antibiotics in the same way filamentous fungi or Actinomycetes are, though some may produce killer toxins or other antimicrobial substances.

Given the options, Actinomycetes are by far the most well-known and significant group of microbes for antibiotic production, especially the genus Streptomyces. \[ \boxed{\text{Actinomycetes}} \]