High light and nitrogen deficiency synergistically lead to biofuel and biomass accumulation in diatoms

Abstract

As a clean energy source, the lipids from microalgae serve as alternatives to fossil oils. There are significant differences in the biofuel and biomass accumulation of microalgae under different environmental conditions. This study investigated the response of biofuel accumulation, photosynthetic capacity, and growth of diatom Thalassiosira pseudonana under stress conditions of high light and nitrogen deficiency, aiming to explore the features of biofuel and biomass accumulation in microalgae under special environmental conditions. The results indicated that the synthesis of chlorophyll was inhibited, leading to reduced light absorption and less damage to the photosynthetic system, with an improvement in electron transport efficiency. Lipid metabolism was more active during the dark cycle, with a 2.89-fold accumulation of fatty acids and a significant increase in the content of neutral lipids (2.39 times). The cell cycle progressed faster, resulting in a marked increase in biomass (1.41 times). These processes consumed a considerable amount of energy, affecting the synthesis of ribosomes. These findings suggest that increasing light exposure and reducing nitrogen supply can achieve the co-accumulation of biofuel and biomass in T. pseudonana.