Respiration-induced biofilm formation as a driver for bacterial niche colonization

Depending on their physiology and metabolism, bacteria can carry out diverse redox processes for energy acquisition, which facilitates adaptation to environmental or host-associated niches. Of these processes, respiration, using oxygen or alternative terminal electron acceptors, is energetically the most favorable in heterotrophic bacteria. The biofilm lifestyle, a coordinated multicellular behavior, is ubiquitous in bacteria and is regulated by a variety of intrinsic and extrinsic cues. Respiration of distinct electron acceptors has been shown to induce biofilm formation or dispersal. The notion of biofilm formation regulation by electron acceptor availability and respiration has often been considered species-specific. However, recent evidence suggests that this phenomenon can be strain-specific, even in strains sharing the same functional respiratory pathways, thereby implying subtle regulatory mechanisms. On this basis, I argue that induction of biofilm formation by sensing and respiration of electron acceptors might direct subgroups of redox-specialized strains to occupy certain niches. A palette of respiration and electron-transfer-mediated microbial social interactions within biofilms may broaden ecological opportunities. The strain specificity of this phenomenon represents an important opportunity to identify key molecular mechanisms and their ecophysiological significance, which in turn may lay the ground for applications in areas ranging from biotechnology to the prevention of antimicrobial resistance.