| In order to investigate the effect of carbon/nitrogen ratio (C/N) on the accumulation of arachidonic acid (ARA) in Mortierella alpina, sodium nitrate (inorganic nitrogen) and urea (organic nitrogen) were selected as the representative nitrogen sources, and M.alpina was fermented at the C/N ratio of 40∶ 1, 20∶ 1 and 10∶ 1, respectively.Changes of dry cell weight (DCW), residual C and N contents in broth during fermentation were measured, the composition and contents of fatty acids in mycelia were also examined by GC-MS, and the correlation analysis of Pearson was carried out between each index.The results showed that with sodium nitrate as the nitrogen source, the DCW （6.42 g/L）obtained under the high C/N condition was significantly higher, which was 2.3 times of that obtained under low C/N, ARA production （0.21 g/L）was also higher, and ARA production was significantly positively correlated with DCW and N consumption under the high C/N condition.With urea as the nitrogen source, the higher DCW（18.2 g/L） was obtained under the low C/N condition, but ARA production was not higher due to the low ARA content in mycelia.Moreover, under the same C/N condition, the DCW and ARA production of mycelia were much higher than those with sodium nitrate as the nitrogen source.With urea as the nitrogen source, ARA production was significantly positively correlated with DCW, C consumption, N consumption and total fatty acid content under different C/N conditions. In summary, organic nitrogen was more beneficial to the growth of M.alpina and ARA accumulation than inorganic nitrogen, and the medium C/N of urea was more conducive to increase the production of ARA（0.99 g/L）.c |
