Citric Acid Production by Yeast Grown on Glycerol-Containing Waste from Biodiesel Industry
Svetlana V. Kamzolova1*, Alina R. Fatykhova1, Emiliya G. Dedyukhina1, Savas G. Anastassiadis2, Nikolay P. Golovchenko1 and Igor G. Morgunov1
1G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, pr-t Nauki 5, Pushchino, RU-142290 Moscow Region, Russia
2Pythia Institute of Biotechnology, Avgi, GR-57002 Thessaloniki, Greece
Article history:
Received March 3, 2010
Accepted August 16, 2010
Key words:
Yarrowia lipolytica, citric acid production, biodiesel production, glycerol, glycerol-containing waste
Summary:
The possibility of using glycerol and glycerol-containing waste from biodiesel manufacture as a carbon and energy source for microbiological production of citric acid has been studied. Acid formation on the selective media had previously been tested in 66 yeast strains of different genera (Candida, Pichia, Saccharomyces, Torulopsis and Yarrowia). Under growth limitation by nitrogen, 41 strains (belonging mainly to species Yarrowia lipolytica) produced acids; unlike 25 strains of the genera Debaryomyces, Candida, Pichia, Saccharomyces and Torulopsis. Among the 41 acid-producing strains, mutant strain Yarrowia lipolytica N15 was selected since it was able to produce citric acid presumably in high amounts. The citric acid production by the selected strain was studied in dependence on the medium pH, aeration and concentration of glycerol. Under optimal conditions, the mutant Y. lipolytica N15 produced up to 98 g/L of citric acid when grown in a fermentor with the medium containing pure glycerol, and 71 g/L of citric acid when grown on glycerol-containing waste. The effect of growth phases on physiological peculiarities of the citric acid producer was discussed.
*Corresponding author: 
++7 496 773 0742
++7 495 956 3370