Microbial Adhesion and Biofilm Formation on Microfiltration Membranes: A Detailed Characterization Using Model Organisms with Increasing Complexity

P. Declerck,I. F. J. Vankelecom,A. Piasecka,C. Denis,L. Vanysacker

doi:10.1155/2013/470867

Abstract

Since many years, membrane biofouling has been described as the Achilles heel of membrane fouling. In the present study, an ecological assay was performed using model systems with increasing complexity: a monospecies assay using Pseudomonas aeruginosa or Escherichia coli separately, a duospecies assay using both microorganisms, and a multispecies assay using activated sludge with or without spiked P. aeruginosa. The microbial adhesion and biofilm formation were evaluated in terms of bacterial cell densities, species richness, and bacterial community composition on polyvinyldifluoride, polyethylene, and polysulfone membranes. The data show that biofouling formation was strongly influenced by the kind of microorganism, the interactions between the organisms, and the changes in environmental conditions whereas the membrane effect was less important. The findings obtained in this study suggest that more knowledge in species composition and microbial interactions is needed in order to understand the complex biofouling process. This is the first report describing the microbial interactions with a membrane during the biofouling development.

Highlights

Bacterial biofilms are ubiquitous in the environment and can be found on almost any hydrated surface
The findings obtained in this study suggest that more knowledge in species composition and microbial interactions is needed in order to understand the complex biofouling process
No membrane effect was found for E. coli during the adhesion and biofilm formation

Summary

Introduction

Bacterial biofilms are ubiquitous in the environment and can be found on almost any hydrated surface. It is known that when species are occurring in a biofilm, they behave differently by changing their gene expression and growth rate [6]. They undergo a transition from a planktonic (“loner”) to a community-based existence in which they interact with various bacterial species in close proximity [7]. From a membrane biofouling point of view, it is important to understand these bacterial interactions This will lead to a complete comprehension of what exactly happens on the membrane surface, but it will allow to improve filtration processes and fouling control strategies.

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Discussion

Conclusion