Abstract: A colorimetric method for rapidly detecting neutral lipid content in yeast was developed, which was based on the staining of yeast cells by lipophilic dyes Oil red O or Sudan Black B and extraction with ethanol after cell rupturing using the method of combining hydrochloric acid or sodium hydroxide with heating. The extraction of Oil red O is better and the colorimetric results were more accurate, while Sudan Black B also can be used as an alternative dye for estimating neutral lipid content. Furthermore, the changes of neutral lipids in yeast mutated phospholipid fatty acid phosphatase（PAH1）and triglyceride lipase（TGL）, which are known as two key genes to regulate triglyceride metabolism, were studied using this method. Disruption of PAH1 resulted in a remarkable decrease in triglyceride content, although total neutral lipid levels did not change；while triglyceride and total neutral lipids contents were significantly accumulated in TGL knockout mutant. Finally, the dynamic changes of yeast neutral lipids content were successfully monitored with the change of growth phase by this method, suggesting that the neutral lipids were obviously accumulated after exponential phase.

Key words: Saccharomyces cerevisiae, Neutral lipids, Lipophilic dyes, Regulation of lipid metabolism