Electronic Journal of Biotechnology ISSN: 0717-3458  
© 2010 by Pontificia Universidad Católica de Valparaíso -- Chile  
   
TECHNICAL NOTE

Breeding of high lipid producing strain of Geotrichum robustum by ion beam implantation

Yuanyuan Cao
Key Laboratory of Ion Beam Bioengineering
Institute of Plasma Physics
Chinese Academy of Sciences
College of Life Science
Anhui Agricultural University
PR China

Jianming Yao*
Key Laboratory of Ion Beam Bioengineering
Institute of Plasma Physics
Chinese Academy of Sciences
PR China
E-mail: yy721@hotmail.com

Jun Li
Anhui Academy of Recycling Economical and Technical Engineering
PR China

Xiangsong Chen
Anhui Academy of Recycling Economical and Technical Engineering
PR China

Jinyong Wu
Anhui Academy of Recycling Economical and Technical Engineering
PR China

*Corresponding author

Keywords: fatty acids, Geotrichum robustum, high lipid producing strain, ion beam implantation.

Abstract    

To obtain an industrial strain with high lipid yield, the wild strain G0 of Geotrichum robustum was mutated by means of nitrogen ions implantation. Mutagenic effects of strain G0 by low energy N+ ion implantation were studied. The experimental results indicated that the survival rate curve took a “saddle” shape, and the positive mutation rate was increased to 22.00% at the dose of nitrogen ions 2.0x1015 ions/cm2 when the survival rate was 28.60%. By repeated screening, a high lipid producing strain G9 was obtained. The biomass, lipid content and lipid yield of the mutant can reach 40.25 g/L, 71.14% and 28.63 g/L after cultured in a 5 L fermenter for 8 days, increasing by 52.81%, 68.82% and 157.93% to those of wild strain, respectively. Analysis results on fatty acids composition and relative content by gas chromatography and mass spectrometry showed that the lipid in strain G9 was mainly composed of 16-carbon and 18-carbon fatty acids, including 37.360% oleic acid, 23.631% palmitic acid, 4.458% linoleic acid and 26.465% stearic acid. Such compositional features were quite similar to plant oil. Geotrichum robustum strain G9 may be an ideal high lipid producing strain for biodiesel production.

Supported by UNESCO / MIRCEN network