Question

Traditional method for the commercial production of citric acid is by:

• A. Batch fermentation
• B. Continuous fermentation
• C. Synchronous production
• D. Solid state fermentation

Hint:

Batch fermentation is ideal for the production of citric acid because it allows precise control over environmental conditions like pH and oxygen supply, which are crucial for optimal yield.

Answer 1

The Correct Option is A

Citric acid has historically been manufactured using a single, well-established fermentation format rather than the more specialised alternatives.
Continuous fermentation keeps feeding in fresh medium and removing product without stopping, a more modern, less standard approach for citric acid.
Synchronous production and solid state fermentation are specialised techniques used in narrower contexts, not the traditional industrial method.
Batch fermentation, where a fixed volume of medium is fermented for a set period and harvested at once, is the long-established, traditional method for commercial citric acid production.
So the correct answer is Batch fermentation.

Answer 2

Approaching this through the biology of citric acid production, using Aspergillus niger grown under controlled batch conditions, helps confirm which format is historically the traditional one.

1. Batch fermentation: Aspergillus niger is grown in a fixed volume of a sugar-rich medium under carefully controlled aeration and pH, and the whole batch is fermented together and harvested at the end of the cycle; this is the classical setup that has been used industrially since citric acid fermentation was first commercialised.
2. Continuous fermentation: Maintaining a continuous feed for a fungal culture producing citric acid is harder to control for consistent yield and purity, which is why this format has not become the traditional standard.
3. Synchronous production: This concept is more relevant to cell-cycle research in microbiology than to the practical, large-scale manufacture of an industrial acid.
4. Solid state fermentation: While useful for certain enzyme and biomass production processes, it has not been the historical basis for citric acid manufacturing at industrial scale.

Looking at how Aspergillus niger has traditionally been cultured for citric acid confirms the batch process as the established method.

Therefore, the correct answer is Batch fermentation.