Apart from the fact that methane as natural gas, it is widely used energy source and important raw material in chemical industry it still has other importance in several areas of human life. Amongst the contemporary global issues one of the most important one is global warming and the processes leading to this phenomenon. Though concerning the greenhouse effect the focus is on carbon-dioxide, there are other gases contribution of which is also substantial. Methane is one these gases and is characterized as much more efficient in this sense as CO2. The main atmospheric methane sources are artificial (industrial and agricultural), also natural. Important examples of the latter are marsh fields, deep ocean, and polar territories. Continuous monitoring these territories is becoming increasingly important recently.
Measuring methane concentration
Though many types of electronic methane sensors are available on the market, it often happens that quantitative precision is not needed at the first step. A good example can be when methane leaking should be mapped on a large marsh field using many test points parallelly. At the first stage, qualitative data are still sufficient in checking whether leaking occurs on a certain point of the field. Moreover, the leaking speed in such area can be minimal, therefore a cumulative measurement provides more accurate and appropriate results.
Household Biogas Plants
Methane is an essential component of artificially produced biogas, as well. Biogas is not only an industrial product of waste management, but widely used in the developing countries by millions of people to ensure the heat for everyday activities, such as cooking and producing hot water. As these family-biogas-plants are usually built from insufficient homemade materials, posing relevant threat for the people use them. The family budget in these countries is far scarce to buy a professional methane sensor so explosions caused by biogas-leaking can’t be predicted in any way.
Our project’s main aim is to develop a methane biosensor using a methanotroph bacteria. It will provide qualitative or hopefully semi-quantitative data on methane concentration of the surroundings in special environment.
Methanotrophs are special bacteria which utilizes one-carbon-compounds (methane, methanol, formaldehyde) as carbon source. Methanococcus capsulatus Bath is a Gram-negative, coccoid aerob methanotroph bacteria which tends to form diplococcus shape by its capsule. The metabolism, genome and transformation possibilities of this species has been studied by many research teams in the last three decades. Several transformed strains are patented in several countries with the aim to produce organic compounds from methane.
The genetic idea in 5 minutes
We would like to create a methane biosensor using methane utilizing bacteria called Methylococcus capsulatus. Our final product would be bacterial medium which changes it’s colour in the presence of methane.
During a sequel of chemical reactions our bacteria converts methane into pyruvic acid, however the widely spread enzyme, lactate dehydrogenase (LDH) is not produced by Methylococcus. As we would like to measure the lactate concentration, we have to add the gene of LDH to Methylococcus capsulatus’ DNA. For that process we will conduct ourselves towards bacterial transformation using plasmids. If we succeed, our bacteria will produce lactate out of methane.
The lactate produced this way can turn the medium’s colour with the help of an assay kit, thus making methane detection possible. Lactate, created by our method, can also be used for the production of polylactate also by the bacteria. Consequently further changes in the bacteria would allow it to directly produce polylactate from methane.