Linearized kinetic model of Listeria monocytogenes biofilm growth

Abstract

In this study the dynamics of biofilm formation on aluminum has been investigated. The process of cell growth has been observed using fluorescence microscopy. It has been confirmed that the process of biofilm formation can be represented as a sum of two separate processes: cell adhesion and colony proliferation. The derived set of equations describes kinetics of surface population growth and characteristic times for adsorption and combined growth processes, including characteristic time for the nutrient supply depletion. All equations contain variables based on the fundamental characteristics of bacterial population and can be easily determined from the experimental data or estimated theoretically. The developed theoretical model allows obtaining realistic values for population growth time and characteristic time for nutrient limitation occurrence during the biofilm development. Resulting equations qualitatively describe the biofilm formation process, and allow predicting microbial kinetics in the batch reactor system and determining critical values of the process parameters.

Biofilm Development by Listeria Monocytogenes

“…Takhistov and George (2004) observed rapid adherence (within 3-5 sec) of a few L. monocytogenes cells to random areas on an aluminium surface. This adherence was initially sparse and uniform but became more clustered over time, eventually leading to the formation of microcolonies.…”

“…Takhistov and George (2004) observed that following the initial attachment of L. monocytogenes, new Biofilms in the Food Environment cells preferentially attach to the extracellular polymeric substances (EPS) produced by the initial adherent cells. They also noted that daughter cells did not detach from the parent cells but instead formed microcolonies, growing toward areas of higher nutrients and fewer cells.…”

“…Takhistov and George (2004) attribute this to the use of the EPS as an energy source. As the EPS is used up, it becomes easier for cells to detach; eventually the EPS becomes weakened to the point that the entire biofilm can detach from the surface.…”

Biossurfactantes: propriedades anticorrosivas, antibiofilmes e antimicrobianas

“…Em geral, a diferença entre a simples adesão do micro-organismo às superfícies e o biofilme pode ser definida através dos seguintes critérios: o papel da superfície no crescimento da população bacteriana e a existência de comunicação célula-a-célula (quorum sensing) dentro da população. 12 Enquanto o termo biofilme se refere a um microambiente complexo em uma superfície, existem vários outros termos que se referem à adesão das bactérias às superfícies. Quando células planctônicas se associam a uma superfície, o termo usual é aderência.…”

“…10 Os biofilmes podem ser formados por populações desenvolvidas a partir de uma única, ou de múltiplas espécies, podendo ser encontrados em uma variedade de superfícies bióticas e/ou abióticas. 13 A adesão bacteriana pode gerar o processo de multiplicação microbiana e formação de biofilme [12][13][14] e pode ser afetado por uma série de fatores como a espécie do micro-organismo, as condições de crescimento e a produção de substâncias extracelulares poliméricas (EPS).…”