Read about the Domain Archaea and choose one interesting species to research. Tr

Question

Read about the Domain Archaea and choose one interesting species to research. Try not to duplicate a species chosen by a classmate, if possible. This is unavoidable if you submit posts simultaneously; however, please scan the discussion area before choosing your species to try to avoid duplication. Find a well-written interesting outside source (scientific journal article, website, etc.) about your species. Present to your classmates a summary of the life history of the species and explain in detail why it was determined to be a member of the Domain Archaea rather than the Domain Bacteria. Remember to include a link to your outside source to enable your classmates to access it.

Explanation / Answer

Domain Archae

1)These are the species which constitute domain of single micro-organisms.

2)These microbes poses property of both prokaryotes and eukaryotes.

3)Archaea and bacteria are generally similar in size and shape.

4) Morphologically they are similer to bacteria.

5)Despite this morphological similarity to bacteria, archaea possess genes and several metabolic pathways that are more closely related to those of eukaryotes, notably the enzymes involves in transcription and translations.

6)These species are special since they lived in some of the most harsh habitat extreme salty areas (halophiles), hot springs ( thermoacidophils) and marshy area (methanogens).

7) Archae differ from the othy bacteria in having a different cell wall structure and this is the features which is responsible for their survival in extreme conditions.

Methanogens

Since fossil sources for fuel and platform chemicals will become limited in the near future, it is important to develop new concepts for energy supply and production of basic reagents for chemical industry. One alternative to crude oil and fossil natural gas could be the biological conversion of CO2 or small organic molecules to methane via methanogenic archaea. This process has been known from biogas plants, but recently, new insights into the methanogenic metabolism, technical optimizations and new technology combinations were gained, which would allow moving beyond the mere conversion of biomass. In biogas plants, steps have been undertaken to increase yield and purity of the biogas, such as addition of hydrogen or metal granulate. Furthermore, the integration of electrodes led to the development of microbial electrosynthesis (MES). The idea behind this technique is to use CO2 and electrical power to generate methane via the microbial metabolism. This review summarizes the biochemical and metabolic background of methanogenesis as well as the latest technical applications of methanogens. As a result, it shall give a sufficient overview over the topic to both, biologists and engineers handling biological or bioelectrochemical methanogenesis.

Introduction

Methanogens are biocatalysts, which have the potential to contribute to a solution for future energy problems by producing methane as storable energy carrier. The very diverse archaeal group of methanogens is characterized by the ability of methane production. The flammable gas methane is considered to be a suitable future replacement for fossil oil, which is about to be depleted during the next decades. Methane can be used as a storable energy carrier, as fuel for vehicles, for the production of electricity, or as base chemical for synthesis and many countries do already have well developed natural gas grids. In terms of the necessary transition from chemical to biological processes, methanotrophic bacteria can use methane as a carbon and energy source to produce biomass, enzymes, PHB. The biological methanation is the main industrial process involving methanogens. These archaea use CO2 and H2 and/or small organic molecules, such as acetate, formate, and methylamine and convert it to methane. Although the electrochemical production of methane is still more energy efficient than the biological production [below 0.3 kWh/cubic meter of methane (0.16 MPa, Bär et al. 2015)], the biological conversion may be advantageous due to its higher tolerance against impurities (H2S and NH3) within the educt streams, especially if CO2 rich waste gas streams shall be used (Bär et al. 2015). Apart from that, research is going on to increase the energy efficiency of the biological process, so that it might be the preferred way of methane production in the future (Bär et al. 2015). Biological methanation occurs naturally in swamps, digestive systems of animals, oil fields and other environments (Garcia et al. 2000) and is already commonly used in sewage water plants and biogas plants. New applications for methanogens such as electromethanogenesis are on the rise, and yet, there is still a lot of basic research, such as strain characterization and development of basic genetic tools, going on about the very diverse, unique group of methanogens (Blasco-Gómez et al. 2017). This review will summarize important facts about the biological properties and possibilities of genetic modification of methanogenic organisms as well as the latest technical applications. It shall therefore give an overview over the applicability of methanogens and serve as a start-up point for new technical developments.

Biochemical and microbial background

Methanogens are the only group of microorganisms on earth producing significant amounts of methane. They are unique in terms of metabolism and energy conservation, are widespread in different habitats and show a high diversity in morphology and physiological parameters.

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