Profiling of fatty acid methyl esters from the oleaginous diatom Fistulifera sp. strain JPCC DA0580 under nutrition-sufficient and -deficient conditions

The marine oleaginous diatom, Fistulifera sp. strain JPCC DA0580, is a promising candidate for biodiesel production due to its high lipid content. In order to truly evaluate the potential of this strain as biodiesel feedstock as well as the impact of nutrition-deficiency to this strain, the proportion of the lipid fractions and fatty acid methyl ester (FAME) derived from Fistulifera sp. cultured under nutrition-sufficient or -deficient conditions were analyzed. The nutrition deficiency led to the increase of the total lipid content in the form of neutral lipids (NLs) accumulation and the decline of polar lipids compared with nutrition-sufficiency. Meanwhile, the total lipid productivity was not significantly changed under two nutrition conditions while the NL productivity under nutrition-deficient condition was much higher than nutrition-sufficient condition. The major FAME components, C14:0, C16:0, C16:1, and C20:5, contribute to over 90 % of total FAMEs under both nutrition conditions. A lower polyunsaturated FAME level were observed in the nutrition-deficient condition (9.9 ± 0.2 %) compared with the nutrition-sufficient condition (19.8 ± 1.2 %), suggesting the availability of the nutrition stress on the strain JPCC DA0580 for improvement of fuel quality as well as productivity. The lipid quality estimation based on the FAME profile revealed that the nutrition-deficiency could further improve the lipid quality of both total lipids and NL fraction. In addition, direct infusion ESI-Q-TRAP-MS/MS was carried out for the fractionated NL in order to estimate triacylglycerol (TAG) composition, suggesting a crucial role of the chloroplast in TAG synthesis.