Matich E K, Ghafari M, Camgoz E, Caliskan E, Pfeifer B A, Haznedaroglu B Z, Atilla-Gokcumen G E
1Department of Chemistry, University at Buffalo, The State University of New York (SUNY), Buffalo, NY 14260 USA.
2Department of Civil, Structural and Environmental Engineering, University at Buffalo, The State University of New York (SUNY), Buffalo, NY 14260 USA.
Biotechnol Biofuels. 2018 Feb 6;11:29. doi: 10.1186/s13068-018-1026-y. eCollection 2018.
Microalgae are uniquely advantageous organisms cultured and harvested for several value-added biochemicals. A majority of these compounds are lipid-based, such as triacylglycerols (TAGs), which can be used for biofuel production, and their accumulation is most affected under nutrient stress conditions. As such, the balance between cellular homeostasis and lipid metabolism becomes more intricate to achieve efficiency in bioproduct synthesis. Lipidomics studies in microalgae are of great importance as biochemical diversity also plays a major role in lipid regulation among oleaginous species.
The aim of this study was to analyze time-series changes in lipid families produced by microalga under different nutrient conditions and growth phases to gain comprehensive information at the cellular level. For this purpose, we worked with a highly adaptable, oleaginous, non-model green microalga species, (a.k.a. ). Using a mass spectrometry-based untargeted and targeted metabolomics' approach, we analyzed the changes in major lipid families under both replete and deplete nitrogen and phosphorus conditions at four different time points covering exponential and stationary growth phases.
Comprehensive analysis of the lipid metabolism highlighted the accumulation of TAGs, which can be utilized for the production of biodiesel via transesterification, and depletion of chlorophylls and certain structural lipids required for photosynthesis, under nutrient deprived conditions. We also found a correlation between the depletion of digalactosyldiacylglycerols (DGDGs) and sulfoquinovosyldiacylglycerols (SQDGs) under nutrient deprivation.
High accumulation of TAGs under nutrient limitation as well as a depletion of other lipids of interest such as phosphatidylglycerols (PGs), DGDGs, SQDGs, and chlorophylls seem to be interconnected and related to the microalgal photosynthetic efficiency. Overall, our results provided key biochemical information on the lipid regulation and physiology of a non-model green microalga, along with optimization potential for biodiesel and other value-added product synthesis.
微藻是一类具有独特优势的生物，可用于培养和收获多种高附加值的生物化学物质。这些化合物大多以脂质为基础，例如三酰甘油（TAGs），可用于生物燃料生产，并且在营养胁迫条件下其积累受到的影响最大。因此，为了提高生物产品合成的效率，细胞内稳态与脂质代谢之间的平衡变得更加复杂。微藻的脂质组学研究非常重要，因为生化多样性在含油物种的脂质调节中也起着重要作用。
本研究的目的是分析微藻在不同营养条件和生长阶段产生的脂质家族的时间序列变化，以在细胞水平上获得全面信息。为此，我们使用了一种高度适应性强、含油的非模式绿色微藻物种（又名 ）。采用基于质谱的非靶向和靶向代谢组学方法，我们在四个不同时间点分析了充足和缺乏氮、磷条件下主要脂质家族的变化，这些时间点涵盖指数生长期和稳定生长期。
脂质代谢的综合分析突出了TAGs的积累，TAGs可通过酯交换用于生产生物柴油，以及在营养缺乏条件下光合作用所需的叶绿素和某些结构脂质的消耗。我们还发现，在营养缺乏条件下，二半乳糖基二酰基甘油（DGDGs）和磺基喹喔啉基二酰基甘油（SQDGs）的消耗之间存在相关性。
营养限制条件下TAGs的高积累以及其他感兴趣的脂质（如磷脂酰甘油（PGs）、DGDGs、SQDGs和叶绿素）的消耗似乎相互关联，并且与微藻的光合效率有关。总体而言，我们的结果提供了关于一种非模式绿色微藻脂质调节和生理学的关键生化信息，以及生物柴油和其他高附加值产品合成的优化潜力。
