Monitoring of bacterial community structure and growth: An alternative tool for biofilm microanalysis

Guilherme O.A Da Silva,Simone Pennafirme,Daniella Da Costa Pereira,Carolina C.C Waite,Ricardo T Lopes,Inayá C.B Lima,Mirian A.C Crapez

doi:10.1016/j.bioflm.2020.100034

Abstract

Microorganisms, such as bacteria, tend to aggregate and grow on surfaces, secreting extracellular polymeric substances (EPS), forming biofilms. Biofilm formation is a life strategy, because through it microorganisms can create their own microhabitats. Whether for remediation of pollutants or application in the biomedical field, several methodological approaches are necessary for a more accurate analysis of the role and potential use of bacterial biofilms. The use of computerized microtomography to monitor biofilm growth appears to be an advantageous tool due to its non-destructive character and its ability to render 2D and 3D visualization of the samples. In this study, we used several techniques such as analysis of microbiological parameters and biopolymer concentrations to corroborate porosity quantified by 2D and 3D imaging. Quantification of the porosity of samples by microtomography was verified by increased enzymatic activity and, consequently, higher EPS biopolymer synthesis to form biofilm, indicating growth of the biofilm over 96 h. Our interdisciplinary approach provides a better understanding of biofilm growth, enabling integrated use of these techniques as an important tool in bioremediation studies of environments impacted by pollutants.

Highlights

Natural science and engineering, strategies to monitor biofilm growth and behavior in response to stress have become a major challenge [1,2,3,4,5], and several methodological approaches are necessary to provide an accurate analysis of the role and potential use of bacterial biofilms
For the bioassay (Fig. 3A–D), we provided an inoculum of 1.63 Â 109 cells. cmÀ3 at time 0 h, representing the minimum biomass necessary for quantification of bacterial cells
Our results demonstrate that computerized microtomography can provide experimental data for ratification of mathematical models of the porous media associated with biofilm growth [53,58,59]

Summary

Introduction

In recent years, imaging techniques have become a great tool for ecological studies involving bacterial biofilms, since they allow visualization of bacterial biofilms as well as bacterial cells [6,7,8]. Depending on the technique employed, other factors can be observed, such as the association of pollutants with biofilms and other substances, and the monitoring of biofilm development over time. For these reasons, imaging techniques that allow monitoring of bacterial biofilms in the environment have become extremely important tools for bioremediation studies [9]. By producing EPS, bacteria create a physically distinct habitat that provides shelter, promotes accumulation of nutrients, and alters both the physicochemical environment of the biofilm and the interactions between the organisms within it [11]

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Conclusion