Bioprocess and Biosystems Engineering

, Volume 36, Issue 11, pp 1787–1796

Influence of flow rate variation on the development of Escherichia coli biofilms

  • J. M. R. Moreira
  • J. S. Teodósio
  • F. C. Silva
  • M. Simões
  • L. F. Melo
  • F. J. Mergulhão
Original Paper

DOI: 10.1007/s00449-013-0954-y

Cite this article as:
Moreira, J.M.R., Teodósio, J.S., Silva, F.C. et al. Bioprocess Biosyst Eng (2013) 36: 1787. doi:10.1007/s00449-013-0954-y

Abstract

This work investigates the effect of flow rate variation on mass transfer and on the development of Escherichia coli biofilms on a flow cell reactor under turbulent flow conditions. Computational fluid dynamics (CFD) was used to assess the applicability of this reactor for the simulation of industrial and biomedical biofilms and the numerical results were validated by streak photography. Two flow rates of 374 and 242 L h−1 (corresponding to Reynolds numbers of 6,720 and 4,350) were tested and wall shear stresses between 0.183 and 0.511 Pa were predicted in the flow cell reactor. External mass transfer coefficients of 1.38 × 10−5 and 9.64 × 10−6 m s−1 were obtained for the higher and lower flow rates, respectively. Biofilm formation was favored at the lowest flow rate because shear stress effects were more important than mass transfer limitations. This flow cell reactor generates wall shear stresses that are similar to those found in some industrial and biomedical settings, thus it is likely that the results obtained on this work can be used in the development of biofilm control strategies in both scenarios.

Keywords

BiofilmsEscherichia coliComputational fluid dynamicsMass transferShear stress

List of symbols

1/b

Parameter related to the mechanical strength of the biofilm (T)

C

Nutrient concentration in the biofilm (M L−3)

Cb

Bulk liquid nutrient concentration (M L−3)

Cs

Nutrient concentration at the biofilm surface (M L−3)

d

Hydraulic diameter (L)

D

Molecular diffusivity of growth-limiting nutrient in water (7.0 × 10−10 m2 s−1 at 30 °C for glucose) (L2 T−1)

Df

Effective diffusivity of growth-limiting nutrient in the biofilm (L2 T−1)

Jp

Biofilm production flux (Mbiofilm L−2 T−1)

Km

External (liquid) mass transfer coefficient (L T−1)

Lf

Average biofilm thickness (L)

mf

Mass of biofilm per unit surface area (Mbiofilm Lbiofilm−2)

N

Nutrient flux to the biofilm surface (M L2 T−1)

Q

Flow rate used in each experiment (L3 T−1)

Re

Reynolds number (ρ v d μ−1)

Sc

Schmidt number (μ ρ−1D−1)

Sh

Sherwood number (KmdD−1)

t

Time (T)

v

Flow velocity (L T−1)

V

Total system volume (L3)

μb

Biofilm specific production rate (T−1)

μ

Viscosity (M L−1 T−1)

ρ

Density (M L−3)

σ

Residence time in whole system (V Q−1) (T)

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • J. M. R. Moreira
    • 1
  • J. S. Teodósio
    • 1
  • F. C. Silva
    • 2
  • M. Simões
    • 1
  • L. F. Melo
    • 1
  • F. J. Mergulhão
    • 1
  1. 1.LEPAE, Department of Chemical Engineering, Faculty of EngineeringUniversity of PortoPortoPortugal
  2. 2.CEFT, Department of Chemical Engineering, Faculty of EngineeringUniversity of PortoPortoPortugal