Application of Pseudomonas.GSN23 bacterium and electrochemical methods for the identification of phenol contaminant

Abstract

Introduction: Phenol is considered to be an important pollutant in the environment and is steadier than other aromatic compounds in industrial treatment. There are several methods for detecting phenol in the wastes. In spite of the high accuracy of these methods, they are time consuming and complex. The utilization of enzymatic biosensors for the identification of phenolic compounds is one of the options and successful techniques. However, the weaknesses of enzymes and high financial expenses cannot be ignored. One of the alternative solutions to overcome the shortcomings of working with enzymes is the utilization of microbial cells in biosensors. In this study, microbial cells were used to design a reasonable and accurate biosensor. Materials and Methods: In this survey, designing of a biosensor was examined using a phenol consuming bacterium. Pseudomonas.GSN23 was acclimatized to high phenol concentrations and immobilized by forming physical and chemical links on working electrodes (glassy carbon and gold interdigitated microelectrodes).Two electrochemical methods (square wave voltammetry and conductometric) were utilized to measure the phenol. Results: In the presence of 1 gram per liter phenol, as the only source of carbon and energy, Pseudomonas. GSN23 consumed 73% of the initial phenol concentration at 32 hours and phenol consumed completely at 72 hours. This bacterium had positive and repeatable responses in conductometric method for phenol detection in the range of 1-300 milligram per liter. The phenol selectivity of the designed biosensor was estimated 5 times more than other aromatic compounds. Conclusion: Microbial biosensors are practical, stable and resistant to the changes of the experimental media. In this study, Pseudomonas.GSN23 was utilized as a phenol consuming bacterium and by conductivity measurement; repeatable responses were acquired in detecting this contaminant.

Keywords

• phenol
• biosensor
• pseudomonas.gsn23
• conductometry
• square wave voltammetry