Absence of Key Biofilm Components Affect Cell Performances in Escherichia coli

Abstract:

Escherichia coli possesses a complex and diverse array of extracellular biofilm components. These biomolecules not only consume a large amount of energy and substrates during their synthesis and assembly, but certain components also present huge risks for pathogenicity. In order to mitigate the adverse effects, Crisp-Cas9 gene-editing method was employed to remove non-essentia biofilm components from Escherichia coli MG1655 at the genetic level. A series of mutant strains with deleted non-essential biofilm components were constructed, and the cellular characteristics of these mutant strains were investigated to identify those with superior performances. The results showed that knockout of genes encoding flagellum(fliE-R, fliY-T , and flhE-D ), type 4 capsule, sialic acid and poly- β-1,6-glucosamine could promote the growth of mutants in M9 medium. Deletion of flagellar gene clusters flgN-L and exopolysaccharide components enhanced PHB synthesis, while knocking out four gene clusters related to extracellular polysaccharide components or flagella could enhance the membrane permeability. The removal of core polysaccharides from Escherichia coli could remodel metabolic regulation and promote the production of colanic acid.