초록
<P>To utilize CO<SUB>2</SUB> in syngas from coal gasification with H<SUB>2</SUB>S impurity for microalgal biodiesel production, metabolic regulation stimulated by NaHS (an H<SUB>2</SUB>S donor) of carbon allocation and energy supply in <I>Nannochloropsis oceanica</I> were investigated to improve lipid accumulation. Enzyme analysis showed that H<SUB>2</SUB>S (NaHS ≤0.5 mM) enhanced glycolysis and fatty acids synthesis, as well as suppressed the desaturation, elongation, and degradation of fatty acids during intracellular carbon metabolism. Additionally, H<SUB>2</SUB>S transformed the main ATP synthesis pathway from oxidative phosphorylation to photophosphorylation and substrate phosphorylation, facilitating efficient energy supply during lipid accumulation. Raman spectra and transmission electron microscopy showed that the peak rate of lipid accumulation increased by 60.2-62.2% in <I>N. oceanica</I> cells exposed to 0.5 mM NaHS. This markedly increased the yields of fatty acid methyl esters (FAMEs) and short-chain FAMEs (C12:0 and C14:0) from <I>N. oceanica</I> cells by 77.0 and 144.4%, respectively, and decreased the unsaturated lipid composition in total FAMEs by 44.8%.</P><P>H<SUB>2</SUB>S in syngas from coal gasification improved lipid accumulation in <I>Nannochloropsis</I> through metabolic regulation, so bio-oil yield was increased by utilizing contaminant without adding cost.</P><BR>[FIG OMISSION]</BR>