Industrial Production of Citric Acid. Application of Citric Acid : (text,p.524) Acidulant in food, confectionary, and beverage (75%) Pharmaceutical (10%), e.g. soluble aspirin preparation - industrial (15%): complexes with metals such as iron and copper to be stabilizer of oil and fats.
Application of Citric Acid: (text,p.524)
- industrial (15%): complexes with metals such as iron and copper to be stabilizer of oil and fats.
- Carbon source: molasses or sugar solution.
- Na-ferrocyanide is added to reduce Iron (1.3 ppm) and manganese (<0.1ppm).
- High dissolved oxygen concentration
- High sugar concentration
- 30 oC.
Bioreactor: batch or fed-batch (100m3)
- The biomass is separated by filtration
- The liquid is transferred to recovery process:
- Separation of citric acid from the liquid: precipitation
calcium hydroxide is added to obtain calcium citrate
tetrahydrate → wash the precipitate→ dissolve it with
dilute sulfuric acid, yield citric acid and calcium
sulfate precipitate → bleach and crystallization →
anhydrous or monohydrate citric acid.
Application of Ethanol:
Candida sp. for lactose or pentose
Genetically modified E. coli
- Carbon source: sugar cane, starch materials (e.g. corn, wheat), cellulosic materials (?!). yield: 0.51 g ethanol/g glucose.
- N, P, minerals.
- 100g/L glucose are inhibitory for yeast.
- 5% (v/v) of ethanol are inhibitory for yeast.
- pH:4-6 for 30-35 oC.
Bioreactor: batch, continuous or with cell recycle
95% conversion of sugars with a residence time of
40 h in batch reactor
21 h in continuous reactor without cell recycle
1.6 h in continuous reactor with cell cycle
By-products: glycerol, acetic acid, succinic acid.
- Distillation to obtaining 95% (w/w) of ethanol-water mixture, followed by
- Molecular sieves to removing water from the mixture to get anhydrous ethanol.