A representative production medium for chlorotetracycline typically contains which set of ingredients?
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ASugar, corn steep liquor, CaCO3, (NH4)2SO4, and NH4Cl
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BCorn steep liquor, CaCO3, and (NH4)2SO4 only
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CSugar, CaCO3, and (NH4)2SO4 only
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DCorn steep liquor, CaCO3, (NH4)2SO4, and NH4Cl (without an explicit sugar)
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EOnly mineral salts without organic nitrogen or carbon sources
Answer
Correct Answer: Sugar, corn steep liquor, CaCO3, (NH4)2SO4, and NH4Cl
Explanation
Introduction / Context:Chlortetracycline production employs complex media that supply carbon, organic nitrogen, and minerals, with buffering to control pH. Corn steep liquor (CSL) provides vitamins and growth factors; CaCO3 helps maintain pH; ammonium salts provide inorganic nitrogen; and a sugar supplies carbon and energy.
Given Data / Assumptions:
- Industrial submerged fermentation with Streptomyces.
- Need for carbon, nitrogen, minerals, and buffering.
Concept / Approach:A complete production medium should include a sugar (glucose/sucrose/starch hydrolysate), CSL for complex nutrients, CaCO3 for buffering, and ammonium salts such as (NH4)2SO4 and sometimes NH4Cl. Omitting sugar or complex nitrogen would not be representative of a balanced production recipe for high titers.
Step-by-Step Solution:
Identify the option that includes carbon source, complex nitrogen, buffer, and mineral nitrogen.Option (a) contains all typical components.Select option (a) as the representative medium.Verification / Alternative check:Multiple published formulations follow this pattern, occasionally substituting specific sugars or adjusting ammonium salt ratios, but the component families remain consistent.
Why Other Options Are Wrong:
- Options lacking sugar or CSL are incomplete for typical high-yield production.
- “Mineral salts only” media are insufficient for complex antibiotic biosynthesis at scale.
Common Pitfalls:Assuming a minimal salts medium can support high secondary metabolite titers without complex nutrients and buffering.
Final Answer:Sugar, corn steep liquor, CaCO3, (NH4)2SO4, and NH4Cl