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

Step 1: Understanding the context.
The production of citric acid is a key industrial process, and there are various methods used for its commercial production. Batch fermentation is the traditional method for producing citric acid, in which microorganisms are grown in a fixed amount of substrate, and the fermentation process is completed in stages.
Step 2: Analyzing the options.
(1) Batch fermentation: Correct — Batch fermentation is the traditional method for the commercial production of citric acid. It involves fermenting a specific amount of medium and harvesting the product after a set period.
(2) Continuous fermentation: This method involves the continuous supply of substrate and removal of products, which is not the traditional method for citric acid production.
(3) Synchronous production: This is a general term for processes where all microorganisms are synchronized, but it is not a specific method for citric acid production.
(4) Solid state fermentation: This method uses solid substrates for microbial growth, but it is not typically used for the large-scale production of citric acid.
Step 3: Conclusion.
The correct answer is (1) Batch fermentation, as it is the traditional and widely used method for producing citric acid.

Answer 2

Citric acid is produced industrially using microbial fermentation, and different fermentation formats exist, so identifying which one is the historically established, traditional method (as opposed to more modern alternatives) answers the question.

1. Batch fermentation: In this method, a fixed volume of medium is inoculated with the fungus (typically Aspergillus niger), left to ferment for a set period, and the entire batch is harvested at the end. This closed, one-cycle-at-a-time approach is the original and still most widely used method for commercial citric acid production.
2. Continuous fermentation: This method feeds fresh medium in and removes product continuously, keeping the culture in a steady state indefinitely; it is a more advanced, less commonly adopted format for citric acid and was not the historically established method.
3. Synchronous production: This term refers to synchronising the growth cycles of a microbial population, a laboratory research concept rather than an established industrial-scale production method for citric acid.
4. Solid state fermentation: This method grows the organism on a solid substrate with little free water, used in some specific processes, but it is not the standard, traditional format used for large-scale citric acid manufacturing.

Among the different fermentation formats, only the batch process matches both the historical development and the still-dominant industrial practice for citric acid.

Therefore, the correct answer is Batch fermentation.