Real-Time iTRAQ-Based Proteome Profiling Revealed the Central Metabolism Involved in Nitrogen Starvation Induced Lipid Accumulation in Microalgae

The study investigated the effects of nitrogen starvation on lipid accumulation in the microalga Chlorella sp. FC2 IITG using iTRAQ-based proteome profiling. Nitrogen starvation significantly increased neutral lipid content from 1% to 54.4% over 120 hours, while protein, carbohydrate, and chlorophyll contents decreased. The study identified 200 differentially expressed proteins, highlighting changes in carbon metabolism, glycolysis, and fatty acid metabolism. Key proteins involved in nitrogen assimilation, photosynthesis, energy pathways, and fatty acid metabolism were differentially expressed, with up-regulation of enzymes related to amino acid biosynthesis and protein degradation. The study emphasized the role of glycolysis and the pentose phosphate pathway in redirecting energy towards lipid biosynthesis, providing insights into metabolic adjustments in microalgae under nitrogen starvation, which could inform biofuel production strategies. Despite challenges in commercial scalability, Chlorella sp. was highlighted as a potential candidate for biofuel production due to its high lipid accumulation and adaptability to nitrogen starvation.