Modeling of the Bacillus subtilis Bacterial Biofilm Growing on an Agar Substrate.

Xiaoling Wang,Mudong Hao,Guoqing Wang

doi:10.1155/2015/581829

Xiaoling Wang, Mudong Hao + Show 1 more

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https://doi.org/10.1155/2015/581829

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Abstract

Bacterial biofilms are organized communities composed of millions of microorganisms that accumulate on almost any kinds of surfaces. In this paper, a biofilm growth model on an agar substrate is developed based on mass conservation principles, Fick's first law, and Monod's kinetic reaction, by considering nutrient diffusion between biofilm and agar substrate. Our results show biofilm growth evolution characteristics such as biofilm thickness, active biomass, and nutrient concentration in the agar substrate. We quantitatively obtain biofilm growth dependence on different parameters. We provide an alternative mathematical method to describe other kinds of biofilm growth such as multiple bacterial species biofilm and also biofilm growth on various complex substrates.

Highlights

A biofilm is an assemblage of microbial cells that is irreversibly associated with a surface and enclosed in an extracellular matrix which are secreted by bacteria [1]
The biofilm in liquid environment is fed on nutrient from the sides, top, and substrate; the models for them described their heterogeneous structures and growth characteristics [5,6,7,8], due to osmotic pressure or extracellular polymeric substances (EPS) [9,10,11]
The biofilm growing on solid nutritive substrate is exposed to air and only fed through bottom substrate, which contains ions salts and nutrient for biofilm growth, and models for this kind of biofilm described a fractal colony with various morphologies through the diffusion-limited aggregation process [12, 13], studying the role of osmotic stress in biofilm spreading based on the physics of polymer solutions [14]

Summary

Introduction

A biofilm is an assemblage of microbial cells that is irreversibly associated with a surface and enclosed in an extracellular matrix which are secreted by bacteria [1]. Scientists did a lot of work on biofilm, such as biofilm morphology, structures, and growth process They proposed models on biofilm to better understand its growth. These models are established for two types of biofilms: one is growing in liquid environment and the other is growing on solid nutritive substrate. The biofilm in liquid environment is fed on nutrient from the sides, top, and substrate; the models for them described their heterogeneous structures and growth characteristics [5,6,7,8], due to osmotic pressure or extracellular polymeric substances (EPS) [9,10,11]. The biofilm growing on solid nutritive substrate is exposed to air and only fed through bottom substrate, which contains ions salts and nutrient for biofilm growth, and models for this kind of biofilm described a fractal colony with various morphologies through the diffusion-limited aggregation process [12, 13], studying the role of osmotic stress in biofilm spreading based on the physics of polymer solutions [14]

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