A Fast-Pass, Desorption Electrospray Ionization Mass Spectrometry Strategy for Untargeted Metabolic Phenotyping

Area of Science:

• Analytical Chemistry
• Metabolomics
• Biotechnology

Background:

• Desorption electrospray ionization mass spectrometry imaging (DESI-MSI) enables direct analysis of small molecules for bacterial metabolic phenotyping.
• Accelerating the screening of mutant libraries is crucial for advancing metabolic engineering.

Purpose of the Study:

• To develop a high-throughput DESI-MSI workflow for rapid metabolic phenotyping of engineered bacteria.
• To implement a single raster line-scan strategy for subminute data acquisition.
• To enable efficient screening of mutant libraries for biofuel applications.

Main Methods:

• Developed a high-throughput DESI-MSI workflow named "Fast-Pass".
• Utilized a single raster line-scan strategy for rapid data collection.
• Applied the workflow to analyze genetically edited *Escherichia coli* strains engineered for free-fatty acid (FFA) production.

Main Results:

• Demonstrated capability for full metabolic profiling in approximately 40 seconds per sample.
• Acquired location-resolved molecular information from engineered strains on a subminute time scale.
• Enabled simultaneous readouts of strain-specific chemical profiles and comparative measurements of FFA production.

Conclusions:

• The "Fast-Pass" DESI-MSI workflow significantly accelerates the metabolic phenotyping of engineered bacteria.
• This method facilitates efficient screening of mutant libraries for bioproducts like FFAs.
• Untargeted DESI-MSI provides comprehensive molecular insights for strain characterization and optimization.