Continuous flow system for biofilm formation using controlled concentrations of Pseudomonas putida from chicken carcass and coupled to electrochemical impedance detection

Abstract

Most studies dealing with monitoring the dynamics of biofilm formation use microbial suspensions at high concentrations. These conditions do not always represent food or water distribution systems. A continuous flow system capable of controlling the concentration of the microbial suspension stream from 10⁴ to 10⁶ CFU ml⁻¹ is reported. Pseudomonas putida biofilms formed using 100-fold, 1,000-fold or 10,000-fold diluted bacterial suspensions were monitored in-line by electrochemical impedance spectroscopy (EIS) and total plate counts. Randles equivalent circuit model and a modified Randles model with biofilm elements were used to fit the EIS data. In Randles equivalent circuit, the charge transfer resistance decreased as the biofilm formed. The log colony counts of the biofilm correlated to the charge transfer resistance. In the biofilm model, the biofilm resistance and the double layer capacitance decreased as the biofilm formed. The log colony counts of the biofilm correlated to the biofilm resistance.

Keywords:

• Biofilm
• flow system
• electrochemical impedance spectroscopy

Acknowledgements

The authors are grateful to Dr Mark Harrison and Gwen N. Hirsch for providing the cell cultures and assisting with the microbiological methodologies. The authors are also grateful for the financial support for Mr Daoyuan Yang from the University of Georgia, College of Agricultural and Environmental Sciences.

Disclosure statement

No potential conflict of interest was reported by the author(s).