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 2.0 x 1015
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 5L 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