Summary
Most microorganisms have the capacity to grow in a surface-attached state, in
which they live as multicellular communities embedded in an extracellular
polymeric matrix. These, so-called, biofilms provide the environment for
microorganisms to display altered behaviour as compared to their planktonic
life style. Biofilms might increase the cell-resistance to antimicrobials as
they can function as protective barriers against the environment. Moreover,
microenvironments provided within the biofilm could increase the heterogeneity
within the population. This variety in behaviour complicates control of
microbial contaminants.
This project will provide mechanistic insights into the factors contributing to
biofilm formation and persistence, in processing environments, aiming to
enhance control of both biofilm formation and (re)contamination of food
products.
The project is organised in four sub-projects targeting biofilms encountered in
different food-related industrial environments: Lactobacillus biofilms,
biofilms of thermophilic and mesophilic spore formers and mixed-species
biofilms. In 2012, the impact of strain diversity on biofilm-forming capacity
was determined, under various conditions relevant to a food environment, by
using both reference strains and isolates obtained from industry. Mechanistic
aspects were evaluated by exploiting available mutants (Lactobacillus
plantarum) and newly-constructed mutants (Bacillus cereus) to target
cell-surface functionalities and resulted in the identification of several
genes affecting biofilm formation. Gene expression during biofilm development
was analysed, for thermophilic spore formers and single species biofilms of
Listeria monocytogenes, using microarray technology. Further experimental
approaches to understanding biofilm formation include studies targeting
population, single cell and molecular levels as well as comparative genomics
methodologies.
TI Food and Nutrition Project Leader: Dr Masja Nierop Groot
Time Frame 2011 – 2014