Augmenting Escherichia coli Count in Anaerobic Sludge by Isolation and Enrichment for Enhancing the Performance of Microbial Fuel Cell
摘要
Microbial fuel cell (MFC) is a promising technology to efficiently treat wide range of wastewater along with generation of electricity. However, improving the energy recovery in MFC remains a key challenge due to inefficient anodic inoculum. This study aims to develop a novel approach to evaluate the impact of augmentation of E. coli in dual chamber MFC to efficiently degrade the azo dye Methylene blue. E. coli is a well-known facultative anaerobic bacterium. Its low nutritional requirement and rapid growth make it one of the most frequently used bacterial models for electrochemical oxidation using various carbon sources. Some respiratory enzymes such as dehydrogenase have the capability to release electrons through oxidization. This property of E.coli is explored in the present study. Since the electron shuttling is less using E.coli; an augment strategy has been performed to degrade the azo dye. The performance of MFCs were evaluated through polarization, voltammetry, COD removal efficiency and coulombic efficiency. MFC-1 (E. coli augmented) recovered a power density of 2.526 mW/m2 at a coulombic efficiency of 16.5%, significantly higher than that of control MFC-2 with raw sludge (0.924 mW/m2 and 10.5%, respectively). Moreover, it showed 96% MB removal after 48 h of operation. Electrochemical analyses demonstrate the enhanced biocatalytic activity of the anode in MFC-1, attributed to the enriched E. coli biofilm, compared to the anode in MFC-2. Therefore, the results obtained in this study highlight the applicability of this simple and efficient selective microbial enrichment strategy for large-scale system development.