Microbial fuel cells and genomics: A review

Abstract

With the depletion of fossil fuels, the world is looking towards green energy and environmentalists are emphasizing the importance of green electricity production. Huge quantities of biodegradable waste from various sources that are not recycled or treated properly are polluting the natural resources [1]. There are many challenges associated with the disposal or reuse of biowastes and in this scenario, Microbial Fuel Cells (MFCs) comes into the picture. MFCs generate electricity and hydrogen using wastewater and also bring down the concentration of organic pollutants present in the wastewater thereby purifying it to an extent. Exoelectrogens either present in the wastewater or added externally, break down the organic matter into simpler compounds. One of the parameters that significantly affect the performance of MFC is the microorganisms and to improve the efficiency of MFC, various microorganisms need to be explored and the best ones should be employed.  With the help of genomics, microorganisms that are suitable for enhancing the efficiency of MFC can be found. Electricity is generated in MFC through the transfer of electrons from anode to cathode. On the other hand, electrons can be used by microorganisms at the anode to reduce compounds such as carbon dioxide into methane which can decrease atmospheric carbon dioxide. Microorganisms are also used for biofuel and bioenergy generation. Researchers, using genomics, are aiming to identify microalgae or macroalgae capable of producing carbohydrates and oils from which ethanol and biodiesel can be synthesized respectively. Algae can also produce biohydrogen and biomethane which are also green alternative fuels.

Genomics can play a major role in better understanding of MFCs and enhance their performance with the help of tools such as Pyrosequencing, PCR/RT-qPCR, Restriction fragment length polymorphism (RFLP), Illumina Sequencing, Mutagenesis: Crispr Cas9, Restriction Enzyme-based, etc. With the amplification of certain strains in microbes, the output of the MFC can be enhanced and the engineered organisms slowly became an integral part in place of the native microbes [2]. Hence, the choice of a specific microbial strain for the operation of MFC for the long term becomes a necessity. In conclusion, there needs to be more research done on the pathways and particularly which strains of microbes when amplified can give good results and experimentation done on genetic modification of microbes to provide better output.

This paper provides an overview of MFCs, their working principle, the role of genomics in MFC, a few genomic tools suitable for the purpose, advantages, challenges, and future scope.