Antibiotics classification in industrial microbiology: which one of the following is a well-known natural cephalosporin antibiotic produced by the mold formerly known as Cephalosporium acremonium (Acremonium chrysogenum)?

Introduction / Context:
Industrial microbiology categorizes beta-lactam antibiotics into penicillins and cephalosporins. Among the earliest cephalosporins isolated from the mold Cephalosporium acremonium (now Acremonium chrysogenum) is cephalosporin C, which served as a crucial starting point for many semisynthetic, clinically used cephalosporins. This question checks recognition of the classic natural cephalosporin molecule associated with that organism and clarifies similar-sounding but different compounds.

Given Data / Assumptions:

• The focus is specifically on a well-known natural cephalosporin produced by the Acremonium lineage.
• Options list compounds with different origins and classes; only one matches the precise description asked.
• The learner is expected to distinguish cephalosporins from other antibiotics and metabolites by name and historical source.

Concept / Approach:
Cephalosporin C is the hallmark natural cephalosporin isolated from Cephalosporium acremonium. While other compounds may be beta-lactams or antibiotics, the question narrows the correct choice to the prototypical, textbook cephalosporin derived from the Acremonium mold, not to similarly named metabolites or unrelated antifungals.

Step-by-Step Solution:

Verification / Alternative check:
Textbook histories of beta-lactams consistently cite cephalosporin C as the Acremonium-derived natural cephalosporin used as a precursor for multiple cephalosporin generations.

Why Other Options Are Wrong:

• Synnematin: Not a classic cephalosporin; different metabolite class.
• Cephalosporin N: Historically confusing; not the hallmark Acremonium product sought in the question.
• All of these: Incorrect because not all listed compounds are cephalosporins from Acremonium.
• Amphotericin B: A polyene antifungal, not a cephalosporin.

Common Pitfalls:
Choosing by name similarity alone; assuming “N” and “C” variants are interchangeable; overlooking organism-specific provenance when classifying natural products.

Final Answer:
Cephalosporin C