Novel high-throughput detection method to assess bacterial surfactant production

Area of Science:

• Microbiology
• Biotechnology

Background:

• Biosurfactants are surface-active compounds produced by microorganisms.
• Detecting and quantifying biosurfactants is crucial for understanding microbial ecology and for biotechnological applications.
• Existing detection methods, like the water drop collapse method, have limitations in sensitivity and throughput.

Purpose of the Study:

• To develop a novel, sensitive, and high-throughput assay for detecting biosurfactants on agar plates.
• To utilize this assay for screening bacterial mutants with altered biosurfactant production.
• To identify novel regulators of biosurfactant biosynthesis in *Pseudomonas syringae* pv. *syringae* B728a.

Main Methods:

• Development of an atomized oil assay using an airbrush to apply a fine mist of oil droplets onto agar plates.
• Application of the assay to screen transposon mutants of *Pseudomonas syringae* pv. *syringae* B728a for altered biosurfactant production.
• Analysis of identified mutants for changes in swarming motility and transcription of the syringafactin biosynthetic cluster.

Main Results:

• The atomized oil assay allows for instantaneous visualization of biosurfactant halos around colonies.
• This novel method is more sensitive than the water drop collapse method and can detect a wide range of surfactants.
• Screening identified *Pseudomonas syringae* pv. *syringae* B728a mutants with altered biosurfactant halos, swarming motility, and syringafactin gene cluster transcription.
• Novel regulators of the syringafactin biosynthetic pathway were discovered.

Conclusions:

• The atomized oil assay is a versatile and sensitive tool for biosurfactant detection and screening.
• This assay facilitates the identification of bacterial mutants with significant alterations in biosurfactant production.
• The study uncovered new insights into the regulation of biosurfactant biosynthesis in *Pseudomonas syringae*.