Screening technique on the selection of potent microorganisms for operation in microbial fuel cell for generation of power

Abstract

This paper focuses on determination of the influence of electrochemically active mi­cro­or­ga­ni­sms on the transmission of electrons from the respiratory enzymes to the electrode and as­sembling of exoelectrogens to the simulated wastewater medium. In this study, the total of eight microorganisms were experimentally tested to exhibit growth and high iron-reducing ability in the absence of mediators. A major connection was observed between the growth and iron-reduction ability of the micro­organism. The growth and iron-reduction ability were monitored experimentally over time. Based on output data, the screening was done among eight different micro­organisms, where Escherichia coli -K-12 was chosen as the most potent micro­organism for its wide application in a microbial fuel cell (MFC). In the present study, various biochemical process factors were optimized statistically using Tagu­chi metho­dology for the rapid development of growth and iron-reducing assay conditions. The design of various experimental trials was carried out using five process factors at three levels with orthogonal arrays (OA) layout of L18. Five process factors, including quantity of lactose, volume of trace element solution, inoculum percentage, pH, and temperature, were taken into consideration as imperative process factors and optimized for evaluation of growth of bacteria and iron reduction ability. The larger-is-best signal to noise (S/N) ratio, together with analysis of variance ANOVA, were used during optimization. Anticipated results demonstrated that the enhanced bacterial growth of 124.50 % and iron reduction ability of 112.6 % can be achieved with 8 g/L of lactose, 2 ml of trace element solution, 4 % (v/v) of inoculum, pH 7, and temperature of 35 oC. Furthermore, the growth and iron reduc­tion time profiles of Escherichia coli-K12 were performed to determine its feasibility in MFC. Open circuit voltage of 0.555 V was obtained over batch study on a single chamber microbial fuel cell (SCMFC).

Keywords

• bioelectricity
• exoelectrogenic bacteria
• bacterial growth
• iron-reducing ability
• Taguchi optimization
• batch operation