MENDOSICUTES.pptx

MENDOSICUTES classification of bacteria

1. MENDOSICUTES

2. Mendosicutes are uneven gram stained “methanogenic bacteria’ ’now called as methanogens a nd are classed as Achaea bacteria MENDOSICUTES

3. Methanogens are relatively diverse group of archaea and prokaryotic organism that can be found in various anoxic habits Methanogenic archaea are a very diverse group and some strains can grow under extreme conditions .like exteme high or low temperature . Methanogenic are coccoid or bacilli shape There are over 50 described species of methanogens. They are mostly anaerobic organisms that cannot function in aerobic conditions.

4. Methanogens lack peptidoglycan, a polymer that is found in the cell wall of bacteria. Some methanogens have cell wall composed of psedopeptidoglycan. Other methanogens do not, but have at least one paracrystaline array (s – layer)made of proteins that fit together like jigsaw puzzle. Methanogenic bacteria are considered a critical group of bacteria, because of their polygenetic diversity and the only of hydrocarbon methane. They require anoxia and highly reduced conditions for growth. These bacteria use co2 or methyl group as terminal electron acceptor and produce methane as their catabolic end product.

5. Habitat: They are found in diverse habitat which are associated with decomposition of organic matter ,bogs, anaerobic digesters ,aquatic sediments, hydrothermal submarine vents and geothermal springs. In animals, they are found in rumens of herbivores, mammalian intestines, human oral cavity, guts of insects.

6. Methanogenis is the production of CH4 from either co2 plus H2 or from methylated organic compounds. Process of methanogensis was first demonstrated over 200 years ago by Alessandro volta. The process is strictly anaerobic. A variety of unique co- enzymes are involved in metanogenesis. METANOGENESIS

7. Complex organic compounds cannot be utilized by methanogens. They use only C1 compound and only C2 compounds .Acetate . There are two nutritional groups of methanogens.s Obligate chemolithotrophic methanogens that grow with CO2 plus H2 according to equation CO2 +4H4 4CO2 + 4H2 Some of these organisms live with the quasi – chemolithotrophic substrates HCOOH and CO 4HCOOH 4CO2 +4H2 CO2 +4H4 CH4 +2H2O SUBSTRATES UTILIZED

8. Methylotrophic methanogens that grow with methyl group containing substrates for example Methanol, acetate CH3COOH CH4 + CH2 Organisms such as Methanosarcina barkeri grown on methanol. Here, fourth of the substrate has to be oxidized to CO2 for reducing power generation. CH3OH + H2O CO2 + 6H 3CH3OH + 6H 3CH4 + 3H2O 4CH3 3CH4 + CO2+2H2O

9. Group 2 organisms produce methane directly from methyl groups and not via CO2 Obligate chemolithotropic methanogens do not contain cytochromes which are present in methanogens

10. The first two novel co enzymes discovered in methanogens are co-enzyme M and F420 Co-enzyme M is a simple chemical compound. Its reactive group is merecepot which can be methylated and methyl co-enzyme M is the ultimate a precursor of methane. Co-enzyme F420 is adeazaflavin, it is a redox carrier and its role is analogous to that of ferrodoxin in other anaerobes. Its functions as electron acceptor of hydrogenise and as electron donor in several reduction reactions. NOVEL CO – ENZYMES

11. PATHWAYS OF METHANOGENESIS

12. Formation of methane from bicarbonate The four steps leading to formation of methane of methane bicarbonate are as follows HCO3 + H2 HCOO + H20 HCOO + H2 + H CH2O + H2O CH2O + H2 CH3OH CH3OH + H2 CH4 + H2O HCO3 + H + 4H2 CH4 + 3H20

13. Formation of methane from Acetate Methanosarcina barkeri is a classic and representative species for those methanogenic bacteria that utilize acetate, methanol and methylamine as substrate. Formation of methane from acetate is a oxidoreduction process. First CO and methyl co-enzyme M are produced which is precursor of methane. CO2 is also produced.

14. Formation of methane from Methanol and Methylamine Methanogenesis of methanol and methylamine can be subdivided into two process Oxidation of one fourth of the methyl groups to CO2. Reduction of three fourth of methyl groups into CH4. A methanol coenzyme M and trim ethylamine coenzyme M methyltransferase have been characterized. The methyl group is first transferred to the protein bound 5 hydroxy benzimidazolycobamide. Methyl groups transfer further proceeds to coenzyme M.

15. Methanogens are widely used in anaerobic digesters to treat wastewater as well as aqueous organic pollutants. Industries have selected methanogens for there ability to perform biomethanation during wastewater decomposition there by rendering the process sustainable and cost – effective. ROLE OF METHANOGENS

16. Decomposers used in sewage treatment. Use methane gas as biofuel. Contribute in global warming. Can oxidize iron. Can form symbiotic relation with certain bacteria. IMPORTANCE OG METHANOGENS

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