Expression of fatty acid desaturase genes and fatty acid accumulation in Chlamydomonas sp ICE-L under salt stress

The Antarctic ice microalgae Chlamydomonas sp. ICE-L which is highly resistant to salt stress holds promise in providing an alternative species for the production of microalgal oil. We studied the effects of the alga in confrontation with NaCI stress on the growth, oil yield and expression of fatty acid desaturase genes. The growth rate of Chlamydomonas sp. ICE-L decreased with the gradual increase in NaC1 concentration. Interestingly, we found that the highest lipid content was achieved at 16 parts per thousand, NaC1, reaching 23% (w/w). Meanwhile, the expression of Delta 9ACPCiFAD increased rapidly while Delta 12CiFAD, omega 3CiFAD2 and Delta 6CiFAD showed a delayed elevation in response to altered salt stress. C18:3 was the dominant PUFA, which account for about 75% TFA in Chlamydomonas sp. ICE-L Under 96 parts per thousand, and 128 parts per thousand NaC1 stress, the content of C20:5 almost approached that of C18:3. In contrast, low salinity enhanced the dominance of C18:3 at the expense of C20:3 and C20:5. (C) 2013 Elsevier Ltd. All rights reserved.