Sparks from bacteria can power the future
Establishing the means to harness electrochemically active biofilms will result in a wealth of a new scientific and technological applications.
Electrochemically active biofilms, which can achieve a direct electrochemical connectionwhen they form on a conductive material, may be the basis of a new power source. Biofilms of micro-organismsform naturally on solid surfaces. Until now, they have been seenas harmful, either to human health, or to industrial products. But recent research suggeststhey have properties which can be used to catalyse or control electrochemical reactions, and could lead to a widerange of new products and processes over the next decade.
Recent research has identified the phenomenonof electrochemically active biofilms (EABs). So far, however, these results have come mainly through chance.And while they promise wide-ranging new applications in fields such as bio-energy, bio-remediation, chemical/biological synthesis,bio-corrosion mitigation and biosensors, the science is still at an early stage. Pursuing this research will allowscientists to increase their understanding of biofilms, which form naturally on a wide range of surfaces.A multidisciplinary team of researchers from France, Italy, Germany, Belgium and Portugal, has set out, in an EU-fundedproject, to test a wide range of microorganisms and identify those which are electrochemically active. Rather than growingnew genetically engineered microorganisms, as other research teams are doing, this team will take advantage ofnatural biodiversity and test existing microbial fauna.Over a period of two years, they will screen a range of media, such as aerobic and anaerobic sea waters. Their aim is toidentify the micro-organisms which form EABs through observing their behaviour on different electrodes.
Do it yourself
The challenge then moves on to growing these EABs under laboratory conditions,trying to recreate the properties exhibited in their natural state. The ability to dothis reliably is, of course, the first step in developing industrial applications forEABs. In the laboratory, the team will also attempt to optimise the performance ofthe biofilms. Laboratory work will be devoted to increasingunderstanding of the mechanisms of EAB formation. For example, why onlyspecific organisms appear to be electrically active, the media and conditions in whichthey are electrically active, and the process in which EABs form.
Expanding knowledge
The team brings together a strong range of expertise in electrochemistry, materialsand chemical engineering and microbiology. They aim to build a large, consistent andextensive database of a range of EABs. This will represent a significant increase inknowledge of EABs in particular establishing whether there is a single model ornot. Furthermore, assessing the actual electron transfer rate in the electricalconnections formed will be a major contribution to assessing the feasibility oflinked technologies and applications.Most micro-organisms growing in the naturalenvironment form biofilms on solid surfaces, such as metals, plasticsor ceramics. These are usually seen as producing adverse effects on human health,through infection, or on industrial products, through biodegradation or corrosion, for example.It is estimated that corrosion costs developed countries around 4% of GNP annually, although the underlying causesare not well understood. Improving knowledge of EABs should improve knowledge of the causes of corrosion and, therefore,our ability to prevent it. But harnessing EABs is about much more than correcting negative effects.
Powering the future
The EAB phenomenon is gaining great importance through the hope that it canbring a breakthrough in fuel-cell technology. Applications for EABs might include new synthesis routes in biotechnologyand food production, new strategies for protecting materials, new biosensors,implanted power sources connected directly to metabolisms, and new therapeutic processes.In short, if the early results can be reproduced widely, the application of EABs could represent amassive take-up of natural power from bacteria in a wide range of fields.
