Making Citric Acid

[Caleb]

From one of my chemistry books, I stumbled upon the following equation:

 

C12H22O11 + H2O + 3O2 => 2C6H8O7 + 4H2O

 

The book explains that the product is citric acid, and I already know that the reactant is table sugar. I was wondering how I could make this. Thanks

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I was thinking of burning sugar water somehow. But I don't think that will work...

[jordehwa]

citric acid is maid by the mold Aspergillus niger, as this mold feeds on sugar its waist is Co2 and citric acid, just like Co2 and alcohol are the waist of yeast.

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Start a culture of Aspergillus niger. This fungus is very common in nature and specific strains have been developed which have a very high production rate of citric acid. These strains are available wherever science and agricultural supplies are sold.

 

 

Feed the culture of A. niger simple sugar. This may be sucrose (table sugar) or some medium that contains glucose. The source is typically the most inexpensive source of sugar available, such as hydrolyzed corn starch, corn syrup or molasses. A. niger uses the glucose as food and produces citric acid and carbon dioxide (C02) as waste products.

 

 

Filter the mold out of the culture once the concentration of citric acid in the culture peaks. The remaining solution will be very high in citric acid

 

 

Extract the citric acid. Add calcium hydroxide [Ca(OH)2] to the solution. It will combine with the citric acid to form calcium citrate Ca3(C6H5O7)2, a salt that will precipitate out of the solution. The following equation shows this reaction:

3Ca(OH)2 + 2C3H4[COOH]3OH -> Ca3(C6H5O7)2 + 3H2.

 

 

Regenerate the citric acid with sulfuric acid. The following equation shows this reaction:

3H2SO4 + Ca3(C6H5O7)2 -> 2C3H4[COOH]3OH + 3CaS04. Note the additional product of calcium sulfate (CaSO4).

[UC]

Uh, I don't know how easy A. Niger would be to get a culture of.

 

The balanced reaction may look simple, but it's carefully controlled in steps by enzymes. Burning sugar or anything of the sort would produce precisely a mess. That process is also thermodynamically downhill, so there's a nice payoff of ATP for the organism, I suspect.