Lipid Metabolite Changes Of Two Marine Microalgae During The Growth

The method of analyzing lipid metabolites in microalgae was established using Ultra PerformanceLiquid Chromatography-Electrospray ionization-Quadrupole-Time of Flight Mass Spectrometry(UPLC-ESI-Q-TOF-MS). The mass spectrometry was performed in reflective time-of-flight using electronspraying ionization in both positive and negative mode. Moreover, fatty acyl location in Glycerolipidswas characterized by Triple Quadrupole Tandem Mass Spectrometry(QqQ-MS).The use of the Q-TOF analyzer operating in MSEmode allows the selection and isolation of precursorions with high efficiency, sensitivity and mass accuracy. After the UPLC-Q-TOF analysis of microalgaesamples cultured during the different growth, principal components analysis (PCA) and orthogonalprojection to latent structures discriminant analysis (O-PLS-DA) were performed using the SIMCA-Psoftware for marker selection and identification. According to the data, in Apedinella radians,Harderoporphyrinogen, the lipid class of monogalactosyldiacylglycerol (MGDG), diacylglycerol (DAG),sulfoquinovosyldiacylglycerol (SQDG) and phosphatidylcholine (PC) decreased from exponential phase tostationary phase, by contrast, Harderoporphyrin and betaine lipid (BL) increased. Through investigation,we found most of these lipids contained polyunsaturated acyl. What`s more, dimethyl pyridine N-oxide(DMPO) with different degree of polymerization changed in Apedinella radians. In Nitzschia closteriumf.minutissima, from the exponential phase to stationary phase, the lipid class of PC, MGDG,digalactosyldiacylglycerol (DGDG), SQDG, phosphatidylglycerol (PG) and BL, while Harderoporphyrin,free fatty acids, triacylglycerol (TAG), lyso-DGDG) and lyso-SQDG species showed a trend of increasing.From onset stationary phase to late stationary phase, TAG, SQDG, DGDG, lyso-DGDG and lyso-SQDGspecies showed a trend of increasing, while Harderoporphyrin, free fatty acids and cholesterol sulfateshowed time-dependent decreasing trends. Moreover, in order to analy how the fatty acids changed in thegrowth phase of algae, the fatty acids of Nitzschia closterium f.minutissima were identified and quantifiedby using of Gas Chromatography-Mass Spectrometry. It showed that total saturated fatty acid (TSFA) andtotal monounsaturated fatty acid (TMUFA) proportion increaseda and total polyunsaturated fatty acid(TPUFA) proportion decreased during cultural period. The trends of several fatty acids were inconformance with the change of fatty acyl in total lipids. Lipid metabolite changes during the growthshowed those lipids have experienced different biochemistry processes, which provide powerful data forenergy development in microalgae.