Rapid determination of lipid in Chlorella based on Nile red fluorescence

The Nile red fluorescence method has been successfully applied to determine the lipids in certain microalgae,but it could not be applied in those with thick cell walls.The solvent of dimethyl sulfoxide(DMSO)was introduced to four strains of Chlorella samples as the penetrating agent at an elevated temperature to enhance the combination of Nile red and lipid.In the improved Nile red fluorescence staining method,the microalgae cell with OD540 of 0.8-1.1 was pretreated with 20% DMSO at 35-40 ℃ by water bath,and dyed by adding 15 μL Nile red(concentration 0.1 mg/mL).The fluorescence intensity with the improved method was enhanced.The improved Nile red fluorescence staining method could be used as a rapid detection technique for screening of naturally-occurring algal strains in a broader spectrum for high lipid production.