Article

Overexpression of the ICL1 gene changes the product ratio of citric acid production by Yarrowia lipolytica.

Institut für Mikrobiologie, Technische Universität Dresden, 01062, Dresden, Germany.
Applied Microbiology and Biotechnology (impact factor: 3.42). 01/2008; 77(4):861-9. DOI:10.1007/s00253-007-1205-4
Source: PubMed

ABSTRACT The yeast Yarrowia lipolytica secretes high amounts of various organic acids, like citric (CA) and isocitric (ICA) acids, triggered by growth limitation caused by different factors and an excess of carbon source. Depending on the carbon source used, Y. lipolytica strains produce a mixture of CA and ICA in a characteristic ratio. To examine whether the CA/ICA product ratio can be influenced by gene-dose-dependent overexpression or by disruption of the isocitrate lyase (ICL)-encoding gene ICL1, recombinant Y. lipolytica strains were constructed, which harbour multiple ICL1 copies or a defective icl1 allele. The high-level expression of ICL in ICL1 multicopy integrative transformants resulted in a strong shift of the CA/ICA ratio into direction of CA. On glycerol, glucose and sucrose, the ICA proportion decreased from 10-12% to 3-6%, on sunflower oil or hexadecane even from 37-45% to 4-7% without influencing the total amount of acids (CA and ICA) produced. In contrast, the loss of ICL activity in icl1-defective strains resulted in a moderate 2-5% increase in the ICA proportion compared to ICL wild-type strains on glucose or glycerol.

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    Svetlana V Kamzolova, Alina R Fatykhova, Emiliya G Dedyukhina, Savas G Anastassiadis, Nikolay P Golovchenko, Igor G Morgunov
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    Microbial Cell Factories 08/2012; 11(1):106. · 3.55 Impact Factor
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Keywords

CA/ICA product ratio
 
CA/ICA ratio
 
carbon source
 
defective icl1 allele
 
different factors
 
gene-dose-dependent overexpression
 
growth limitation
 
harbour multiple ICL1 copies
 
high-level expression
 
ICA proportion
 
ICL)-encoding gene ICL1
 
ICL1 multicopy integrative transformants
 
icl1-defective strains
 
moderate 2-5% increase
 
recombinant Y. lipolytica strains
 
sunflower oil
 
total amount
 
various organic acids
 
Y. lipolytica strains
 
yeast Yarrowia lipolytica secretes