Rapid quantification of microalgal lipids in aqueous medium by a simple colorimetric method

Area of Science:

• Biotechnology
• Renewable Energy
• Analytical Chemistry

Background:

• Microalgal lipid productivity is crucial for biofuel development.
• Current lipid estimation methods are time-consuming and labor-intensive.
• Efficient screening of microalgal strains is essential for optimizing biofuel production.

Purpose of the Study:

• To develop and validate a rapid colorimetric method for direct quantitative measurement of microalgal lipids.
• To assess the lipid content of selected microalgal strains using the novel method.
• To establish a faster and more efficient process for microalgal strain screening.

Main Methods:

• Utilized the sulpho-phospho-vanillin (SPV) colorimetric assay for lipid quantification.
• Measured lipid-induced pink color intensity via spectrophotometry at 530nm.
• Validated the SPV method against gas chromatography analysis for accuracy.

Main Results:

• The SPV method allowed direct quantification of lipids in liquid microalgal cultures.
• Lipid content in Chlorella sp., Monoraphidium sp., Ettlia sp., and Nannochloropsis sp. ranged from 10% to 30%.
• High accuracy was confirmed, with R(2)=0.99 when compared to gas chromatography.

Conclusions:

• The sulpho-phospho-vanillin (SPV) colorimetric method provides a rapid and accurate means for quantifying microalgal lipids.
• This method significantly improves the efficiency of screening microalgal strains for high lipid productivity.
• The SPV assay is a valuable tool for advancing renewable biofuel research through faster strain selection.