Applied microbial and cell physiology

Applied Microbiology and Biotechnology

, Volume 94, Issue 4, pp 1095-1105

First online:

Characterization of the mitochondrial NAD+-dependent isocitrate dehydrogenase of the oleaginous yeast Rhodosporidium toruloides

  • Fan YangAffiliated withDivision of Biotechnology, Dalian Institute of Chemical Physics, CASSchool of Biological Engineering, Dalian Polytechnic University
  • , Sufang ZhangAffiliated withDivision of Biotechnology, Dalian Institute of Chemical Physics, CAS
  • , Yongjin J. ZhouAffiliated withDivision of Biotechnology, Dalian Institute of Chemical Physics, CAS
  • , Zhiwei ZhuAffiliated withDivision of Biotechnology, Dalian Institute of Chemical Physics, CAS
  • , Xinping LinAffiliated withDivision of Biotechnology, Dalian Institute of Chemical Physics, CAS
  • , Zongbao K. ZhaoAffiliated withDivision of Biotechnology, Dalian Institute of Chemical Physics, CASDalian National Laboratory for Clean Energy Email author 

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Abstract

Early biochemical studies have demonstrated that lipid accumulation by oleaginous yeasts is linked to the activity of the NAD+-dependent isocitrate dehydrogenase (Idh). However, molecular study of Idh of oleaginous microorganisms remains limited. Here, we present the cloning of a mitochondrial NAD+-specific Idh from Rhodosporidium toruloides (RtIdh), an excellent microbial lipid producer that uses carbohydrates as the carbon source. The evolutionary relationship analyses among RtIdhs and other yeast Idhs revealed that RtIdh had a closer relationship with the Idhs of Ustilago maydis and Schizophyllum commune. We expressed the RtIDH gene in the yeast Saccharomyces cerevisiae idhΔ mutant. Under the nitrogen-limited condition, the intracellular lipid content and extracellular citrate concentration of the culture of the S. cerevisiae idhΔ carrying the RtIDH gene increased as the carbon/nitrogen molar ratio of the media increased, while the wild-type S. cerevisiae strain showed no correlation. Our data provided valuable information for elucidating the molecular mechanism of microbial oleaginicity and for engineering microorganisms to produce metabolites of fatty acid pathway.

Keywords

Rhodosporidium toruloides Microbial lipid NAD+-specific isocitrate dehydrogenase Nitrogen limitation Oleaginous yeast