A Review on Various Microbial Fuel Cells (MFCs) for Power Generation

The growing concerns for environment, health and monetary aspects have triggered a search for efficient and economic renewable sources of energy production. Microbial fuel cell (MFC) is an emerging technology that uses biofilms as catalysts to convert chemical energy in organic (and some inorganic) matters directly into electricity. MFC has a distinct advantage that is it can utilise low-grade biomass or even wastewater, which is otherwise not utilised, to produce bioelectricity. MFC research has intensified in the past decade, and the maximum MFC power density output has been increased greatly, and many types of waste streams have been tested. MFC power output is still much lower than that needed for practical power generation beyond powering small sensors, despite recent advances in reactor design.

Complicated reactor designs may improve power output, but the cost could be prohibitive for practical applications. To reduce capital and operational costs, simple and robust membrane-less MFC reactors are desired, but these reactors require highly efficient microorganisms which efficiently carry the electrons to electrodes. Genetic modifications can create ‘super bugs ’(i.e. high-performance sessile cells) with MFC performance enhancement properties. Newly discovered conductive cell aggregates improved electron transport through hyperpilation via mutation or genetic recombination. To promote MFC performances or fulfil specific needs such as a certain voltage demand, MFC system integration with microbial electrolysis cell (MEC) is a hot research area. Some reported value-added products from MFCs include H₂, methane and H₂O₂. MFCs generate maximum power when subjected to an external resistance that is equal to its own internal resistance. Development of fuel cells with amplified designs and electron-transfer mechanism to electrode can emerge as multidisciplinary approach for current generation, biosensors development, bioremediation, bio-fouling prevention biosynthesis and bio-batteries on biodegradable fuels. The aim of this paper is MFC systems which focus mainly on suitable technology for wastewater, production of bioenergy and bioproducts, and its recent advancement and also effect on engineering parameters.