Non-pathogenic Escherichia coli biofilms: effects of growth conditions and surface properties on structure and curli gene expression

Arch Microbiol. 2020 Aug;202(6):1517-1527. doi: 10.1007/s00203-020-01864-5. Epub 2020 Mar 28.

Abstract

Biofilm formation is a harmful phenomenon in many areas, such as in industry and clinically, but offers advantages in the field of biocatalysis for the generation of robust biocatalytic platforms. In this work, we optimised growth conditions for the production of Escherichia coli biofilms by three strains (PHL644, a K-12 derivative with enhanced expression of the adhesin curli; the commercially-used strain BL21; and the probiotic Nissle 1917) on a variety of surfaces (plastics, stainless steel and PTFE). E. coli PHL644 and PTFE were chosen as optimal strain and substratum, respectively, and conditions (including medium, temperature, and glucose concentration) for biofilm growth were determined. Finally, the impact of these growth conditions on expression of the curli genes was determined using flow cytometry for planktonic and sedimented cells. We reveal new insights into the formation of biofilms and expression of curli in E. coli K-12 in response to environmental conditions.

Keywords: Biofilm; Confocal laser scanning microscopy; Curli; Osmolarity.

MeSH terms

  • Adhesins, Bacterial / biosynthesis*
  • Adhesins, Bacterial / genetics
  • Bacterial Adhesion / physiology
  • Bacterial Proteins / biosynthesis*
  • Bacterial Proteins / genetics
  • Biofilms / growth & development*
  • Environmental Exposure*
  • Escherichia coli / metabolism*
  • Escherichia coli Proteins / genetics
  • Plastics / chemistry
  • Polytetrafluoroethylene / chemistry
  • Stainless Steel / chemistry
  • Surface Properties

Substances

  • Adhesins, Bacterial
  • Bacterial Proteins
  • Escherichia coli Proteins
  • Plastics
  • Stainless Steel
  • Crl protein, Bacteria
  • Polytetrafluoroethylene