Bacteria as a Source of Electricity

Do you know that the earth’s capacity to supply fossil fuels are decreasing day by day and if we continue to utilize our natural resources on current trends then we might have no source of natural energy in another few decades. Have you ever imagined what would happen then? There will be no oil for your cars and no electricity for your daily life!! Can you live that life?

Well this might not be a problem for developed countries that already have alternate energy sources, like nuclear energy for their power supply. But what is the solution for country like Bangladesh? Many of you already got the answer in your mind and that is solar energy. But have you ever imagined that tiny little bacteria, a microorganism that we cannot see with naked eyes could be a source of electricity.

In past few years scientific interests focused into some special group of bacteria, which can convert biochemical to electrical energy, that is during bacterial growth some products released form their body can be used to produce currents. At the beginning of this technology power production was very low but due to some development in recent years electricity production from bacteria has increased dramatically. Although most of the results are from miniature projects but the scientists are very much optimistic to produce energy from microorganisms in near future. At present the major limitations of this technology are the cost of materials used to construct microbial fuel cells. This costing problem is confined to specially those countries that already have enough power plants but may be not a problem for developing countries like Bangladesh as we are lacking of enough energy and we need more and more power plants to supply electricity. In addition we can supply the raw materials (e.g. wastewater) for such plants from our own. Therefore, if we can establish a plant where bacteria and wastewater will be the source of our future electricity, you can easily imagine how much foreign currency we can save.

So, far the bacteria which can produce electricity in microbial fuel cells (MFCs) are Geobacter and Shewanella species. In addition Pseudomonas aeruginosa also shows promising results. The recent discovery of nanowires introduces a whole new dimension in MFCs. These conductive, nanowires scientifically known as pilus-like structures, appear to be directly involved in electron transfer, an important component for electricity production.

At present some of the developed countries are planning to use microbial fuels cells for wastewater treatment. In the United States approximately $25 billion is spent annually for water and wastewater treatment and approximately 4% of the electricity produced is used for the operation of the wastewater infrastructure. A treatment system based on microbial fuel cells provides a great opportunity to develop the technology, because the substrate is free and wastewater must be treated. It has been estimated that at a modern treatment plant of MFC, the wastewater may contain nine times as much energy as is used to treat it. Energy recovery at a wastewater treatment plant could lead not only to a sustainable system based on energy requirements but also to production of a net excess of energy. MFCs would be used in a treatment system as a replacement for the existing energy-demanding bioreactor, resulting in a net energy-producing system. However, it is not known at the moment how to economically scale up a MFC or what would be the cost to replace a conventional system with a MFC-based design. But we have an advantage, as we do not have necessary treatment plants in our country to treat the wastewater; therefore, we need more and more such treatment plants to save the environment as well as save energy by using MFCs.

The MFC system could even be useful for individual homes or other small applications, although power production would probably be too low to warrant recovery of electricity on the basis of at hand technology. However, in near future it could replace the existing generator or IPS to fight against our load shedding problem. At present MFCs may be particularly useful in remote areas where little power needed to run devices, for instance, environmental sensors particularly in river and deep-water environments where it is difficult to routinely access the system to replace batteries and can routinely monitor several environmental factors. Such sensors powered by MFCs are under operations in the United States.

MFCs represent a promising technology for renewable energy production; their most likely near-term applications are as a method of simultaneous wastewater treatment and electricity production. The ability of a diverse range of bacteria to function and persist in MFC is a truly fascinating occurrence. This rapidly evolving technology will fascinate microbiologists and engineers who are challenged with waste technologies and energy production in the coming decades and could be a most suitable energy solution for developing countries like Bangladesh.