Two protocols for the detection of oleaginous bacteria using Oil Red O

Area of Science:

• Biotechnology
• Microbiology
• Biochemistry

Background:

• Selecting oleaginous bacteria for biotechnology typically involves expensive, time-consuming methods.
• Accurate identification of lipid-accumulating microorganisms is crucial for various industrial applications.

Purpose of the Study:

• To develop a specific, rapid, and inexpensive screening methodology for detecting triacylglycerol-accumulating microorganisms.
• To evaluate the efficacy of Oil Red O (ORO) as a staining agent for neutral lipids in bacteria.

Main Methods:

• Utilized Oil Red O (ORO) dye for staining neutral lipids (triacylglycerols and wax esters) on thin-layer chromatography plates.
• Developed and applied a novel agar plate staining methodology for screening triacylglycerol-accumulating bacteria.
• Assessed the detection limits of ORO for specific lipid compounds.

Main Results:

• ORO demonstrated high sensitivity, detecting minimal quantities of tripalmitin and cetylpalmitate.
• The developed screening methodology successfully identified 9 out of 13 strains with >20% triacylglycerol content.
• Polyhydroxyalkanoates-producing bacteria were not stained by ORO, indicating specificity.
• Four oleaginous strains with mucoid morphology were not detected due to extracellular polymeric substances hindering dye entry.

Conclusions:

• Oil Red O staining is a specific and effective method for identifying triacylglycerols in microorganisms.
• The developed ORO-based screening methodology offers a simpler and faster alternative for isolating oleaginous bacteria.
• ORO facilitates the characterization of neutral lipids accumulated by microorganisms as reserve compounds.