Bacterial Motility Enhances Adhesion to Oil Droplets

TL;DR

This study demonstrates that bacterial motility significantly increases adhesion to oil droplets, which is crucial for biodegradation and bioprocessing, with motile bacteria adhering faster and more densely than nonmotile ones.

Contribution

It reveals the role of bacterial motility in enhancing adhesion to oil-water interfaces, a factor previously less understood compared to thermodynamic influences.

Findings

Motile bacteria adhere more rapidly and densely than nonmotile bacteria.

Increasing surfactant concentration reduces bacterial surface density.

Motility enhances bacterial adhesion regardless of surfactant presence.

Abstract

Adhesion of bacteria to liquid-liquid interfaces can play a role in the biodegradation of dispersed hydrocarbons and in biochemical and bioprocess engineering. Whereas thermodynamic factors underpinning adhesion are well studied, the role of bacterial activity on adhesion is less explored.Here, we show that bacterial motility enhances adhesion to surfactant-decorated oil droplets dispersed in artificial sea water. Motile Halomonas titanicae adhered to hexadecane droplets stabilized with dioctyl sodium sulfosuccinate (DOSS) more rapidly and at greater surface densities compared to nonmotile H. titanicae, whose flagellar motion was arrested through addition of a pro-ton uncoupler. Increasing the concentration of DOSS reduced the surface density of both motile and nonmotile bacteria as a result of the reduced interfacial tension.