Isolation and characterization of electroactive bacteria for electricity generation in microbial fuel cell (MFC) supplemented with palm oil mill effluent (POME)

Microbial fuel cell (MFC) converts chemical energy into electrical energy by using the electroactive bacteria (EAB). MFC is capable to generate electricity and treat the wastewater simultaneously. Palm oil mill effluent (POME) is the organic waste which can act as the electron donor for the EAB like Shewanella oneidensi MR-1 to generate electricity. Since the collected POME was pH 10, the experiment was carried out by using the MR-1 as the negative control to compare the electricity generation by the enrichment of alkaline soil sample. From this MFC setup, isolation and characterization have been done to isolate the alkaliphilic EAB from the POME. The electricity generated in MFC by MR-1 was very low compared to the MFC that enhanced by the alkaline soil sample. The highest electricity generated by the MFC with first enrichment by the soil sample was 8.910 W/m2 whereas the second enrichment was 9.119 W/m2 power density. The EAB was isolated from the second enrichment sample by serial dilution and characterized by using techniques such as Gram staining, catalase test and oxidase test. The DNA of the isolated EAB were extracted for DNA sequencing for future identification. This study reported that MR-1 was not suitable for electricity generation in the alkaline environment and alkaliphilic EAB need to be isolated. The isolated alkaliphilic EAB, GR-1 can generate more electricity in the alkaline POME and hence increase the time-interval for the electricity generation. The result of the biochemical test showed that GR-1 was Gram negative cocci shape bacteria and both catalase and oxidase tests showed negative result. This finding provides valuable insights into more extremophiles need to be isolated so it can increase the performance of MFC in any extreme situation.