A simple and rapid protocol for measuring neutral lipids in algal cells using fluorescence

Area of Science:

• Biotechnology
• Renewable Energy
• Analytical Chemistry

Background:

• Algae are promising sources for renewable fuels due to their lipid storage.
• Accurate measurement of algal lipid content is crucial for strain screening and process monitoring.
• Existing gravimetric methods are slow and sample-intensive.

Purpose of the Study:

• To develop a fast and reliable protocol for determining intracellular neutral lipid content in algae.
• To adapt the Nile Red fluorescent dye assay for high-throughput analysis of algal lipid content.
• To provide a method suitable for monitoring algal fermentation bioprocesses.

Main Methods:

• Utilized Nile Red, a lipophilic fluorescent dye, for lipid body detection.
• Employed ethanol for cell membrane permeabilization.
• Implemented a 96-well microplate format for increased sample capacity and fluorescence intensity measurements.
• Tested on the green alga Auxenochlorella protothecoides, using both live and dried samples.

Main Results:

• Developed a simple, fast, and reliable protocol for neutral lipid quantification.
• The Nile Red assay demonstrated effectiveness in measuring lipid content in Auxenochlorella protothecoides.
• The microplate format allows for high-throughput analysis, suitable for bioprocess monitoring.

Conclusions:

• The Nile Red-based fluorescence assay offers a significant improvement over traditional methods for algal lipid quantification.
• This protocol facilitates efficient screening of oil-rich algal strains for biofuel applications.
• The method is adaptable for real-time monitoring of algal lipid accumulation during fermentation.