Commercial production of citric acid is done by fermentation using:
Commercial production of citric acid is done by fermentation using:
Select an option to attempt
Correct Answer: Option A
Explanation
Aspergillus niger for citric acid production:Citric acid (E330) is one of the most widely used food acidulants and is produced industrially by submerged fermentation:• Producing organism: Aspergillus niger (a filamentous fungus)• Carbon source: Sucrose (from sugarcane molasses) or glucose (from starch hydrolysate)• Conditions for maximum citric acid yield:- Low pH (<2.5): suppresses competing organic acids, inhibits phosphofructokinase, favouring citric acid accumulation- Low phosphate and manganese levels: reduces growth, redirects carbon to citric acid- High dissolved oxygen- High sugar concentration (15–20%)• Yield: >90% theoretical conversion of glucose to citric acid• Metabolic basis: Blocks in TCA cycle (low aconitase activity due to low Mn²⁺) cause citrate to accumulate.Global production: ~2 million tonnes/year; used in food, beverages, pharmaceuticals, cleaning products.Answer: Aspergillus niger produces citric acid by submerged fermentation with high yield under acidic, low-phosphate conditions.