Membraneless Microbial Fuel Cell: Characterization of Electrogenic Bacteria and Kinetic Growth Model

Abstract

The generation of electricity in a membraneless microbial fuel cell (ML-MFC) was studied using dewatered sludge containing a mixed culture of electrogenic bacteria (EB). The EB acted as a biocatalyst to enhance the degradation of chemical oxygen demand (COD). Scanning electron microscope (SEM) observations revealed the formation of a biofilm at the anode surface. Phylogenetic analysis proved the presence of Pseudomonas species and Bacillus subtilis, which actively boosted the electron transfer, in the biofilm. Moreover, three unstructured kinetic models for EB growth, namely the logistic, Kono and Asai (KA), and combined continuous logistic and Fermi (CCLF) models, were proposed and validated. The logistic and KA growth models had high R2 (>0.91) and low root-mean-square error (RMSE) (<1.082) values, while the CCLF model showed low values for both R2 (0.48) and RMSE (5.431). The experimental data showed that the logistic model could best describe the growth of EB in the ML-MFC.