Vinegar manufacture typically involves two bioprocess stages. Which sequence correctly describes the overall production path from sugars to acetic acid?

Introduction / Context:
Vinegar production couples two distinct microbial processes: yeast-driven ethanolic fermentation and bacterial oxidation. Understanding the order of these steps is fundamental to designing and operating a vinegar plant efficiently.

Given Data / Assumptions:

• Sugars from fruit/grain are first converted to ethanol by yeasts.
• Acetic acid bacteria subsequently oxidize ethanol to acetic acid in the presence of oxygen.
• Final product is an aqueous acetic acid solution with characteristic flavor.

Concept / Approach:
Yeast fermentation of sugars is largely anaerobic (facultative metabolism), maximizing ethanol yield. Acetification is strictly aerobic, requiring efficient oxygen transfer for rapid conversion of ethanol to acetic acid and to avoid overoxidation losses.

Step-by-Step Solution:

Verification / Alternative check:
All traditional (Orleans) and modern (submerged) processes follow this two-stage biology, confirming the sequence.

Why Other Options Are Wrong:

• Aerobic only or anaerobic only omit one essential step.
• Aerobic followed by anaerobic reverses the real order.
• Pure chemical synthesis is not the standard for food-grade vinegar.

Common Pitfalls:
Confusing oxygen requirements of yeast versus acetic acid bacteria; overlooking that excess aeration in stage 1 lowers ethanol yield.

Final Answer:
Anaerobic fermentation followed by aerobic oxidation