ENV1+2 Flashcards
Which substrates can be used by archaea?
Acetate: Methanosaeta use acetate as electron donor.
Methanosaeta species are acetoclastic methanogens, meaning they have the unique ability to directly convert acetate into methane (CH4) and carbon dioxide (CO2) through a process known as acetoclastic methanogenesis. Acetate serves as both a carbon and energy source for Methanosaeta.
H2, acetate and methanol/methylamine: Metanosarcina use H2, acetate and methanol/methylamine.
Members of the genus Metanosarcina are versatile methanogens capable of utilizing a variety of substrates for methanogenesis. Metanosarcina species can utilize hydrogen gas (H2) as an electron donor and acetate as a carbon and energy source. Additionally, they have the metabolic flexibility to utilize other substrates such as methanol and methylamines (e.g., methylamine, dimethylamine, trimethylamine) for methanogenesis. This versatility allows Metanosarcina to thrive in diverse environments where these substrates are available
Which substrates can be used by archaea for energy and carbon sources?
A) Carbon dioxide
B) Hydrogen gas
C) Methane
D) All of the above
Correct answer: D) All of the above
Archaea can indeed use carbon dioxide, hydrogen gas, and methane as substrates for their metabolic processes. They exhibit diverse metabolic capabilities and can thrive in various environmental conditions.
How can microorganisms get their energy?
Phototrophy : From light
Chemotrophy: From chemical reactions.
Does energy production requires a presence of electron donors?
Yes, the electron donors deliver electrons to the electron transport chain. If these are not delivered then the generation of ATP can not happen
What describes whether a reaction can provide energy for the microorganisms?
It depends on its gibbs free energy change. If negative energy is released and can be used for energy production by microorganisms.
What is denitrification?
From NO3^- to N2 by bacteria.
the microbial process of reducing nitrate and nitrite to gaseous forms of nitrogen, principally nitrous oxide (N2O) and nitrogen (N2).
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The microorganisms for the denitrification is called heterotrophic bacteria which requires organic carbon as food
Denitrification involves the conversion of nitrate to nitrogen gas or nitrous oxide
The final product of denitrification is nitrogen gas
Denitrifying bacteria are primarily responsible for denitrification
Denitrification typically occurs under anaerobic conditions
nitrate as an electron acceptor
Describe the steps of the anaerobic digestion process
From organic matter to CH4 (biogas) and CO2 in the absence of O2.
1. Hydrolysis
2. Acidogenesis (formation of acids)
3. Acetogenesis (formation of acetate)
4. Methanogenesis (Acetate => CO2 + CH4)
- Hydrolysis; Organic matter is broken down into its smaller components (carbohydrates, Proteins, Lipids). Enzymatic process, where H 2 O molecule is splitting the organic macromolecule in smaller units
- acidogenesis: formation of acids by acidogenic microorganisms absorbing the products of hydrolysis through their cell membranes. Intracellular process. At the same time H 2 is produced. Follows branched metabolism, determined by the H 2 level
- acetogenesis: Processing the accumulated volatile fatty acids, ethanol, etc.to acetate and H2.
Intracellular process, At the same time H 2 is produced. Follows linear metabolism, i.e. does not occur unless the H 2 is low enough - methanogenesis. Methane is produced from acetate.
Acetate=> CO2+CH4
4H2+CO2=>CH4+2H2O
What is Chemical Oxygen demand?
COD: Measure of the strength‐/concentration of
wastewater. Describes the amount of O2 to fully
oxidize the organic matter.
It is the amount of oxygen consumed during the oxidation of oxidizable organic matter in the presence of strong oxidizing agent.
High COD levels indicate a higher concentration of organic pollutants, such as carbohydrates, proteins, fats, and other organic compounds, which may require more oxygen for their oxidation
Is lignin biodegradable?
The cell walls consists of 3 macromolecules: cellulose, hemicellulose and lignin.
Lignin: Wire fench that give structure to the wall. complex, crosslinked and 3D aromatic polymers.
Lignin degrade very slowly by microbes due to the complex structure. The degradtion happens under anaerobe conditions. And can therefore not be as an Carbon- and energy source
Cellulose: unbranched polymer of glucose
Hemi-cellulose: branched polymer of various sugar units
What is the characteristic of anaerobic microorganisms?
Can survive without oxygen.
cellular respiration: redox reaction is used to move electrons around to produce ATP.
Metabolic Adaptations: Anaerobic microorganisms utilize alternative electron acceptors in their metabolic pathways instead of oxygen
Oxygen Sensitivity: Anaerobic microorganisms are sensitive to oxygen and may be inhibited or killed by its presence.
Habitat Adaptations: They thrive in environments with low or no oxygen, such as sediments, wetlands, and the gastrointestinal tracts of animals
Why are sulfate-reducing bacteria more competitive than methanogens?
Sulfate reduction is energetically more favorable than methanogenesis. Sulfate reducing bacteria SRB can generate more ATP per molecule of organic substrate compared to methanogens. This higher energy yield allows SRB to outcompete methanogens for shared substrates.
What is cellulose?
Cellulose is a complex carbohydrate, specifically a polysaccharide, that serves as a structural component in the cell walls of plants.
Very long chain polymer of glucose ~10,000 in wood. Cellulose links up in multiple bundles to make fibres. Tight bundles are very resistant to chemical attack
What is branched metabolism?
Branched metabolism refers to metabolic pathways with multiple alternative routes for converting substrates into different products, enhancing metabolic flexibility and adaptability
In which domain of life are methanogens belonging?
Methanogens belong to the domain Archaea. They are a group of microorganisms within the Archaea domain that produce methane (CH4) as a metabolic byproduct of their anaerobic respiration. Methanogens are known for their ability to thrive in extreme environments such as anaerobic sediments, wetlands, and the gastrointestinal tracts of animals.
Which is the main purpose of lignin in plants?
Lignin is a branching material that holds a plant together and keeps the structure of the plant stable.
The main purpose of lignin in plants is to provide structural support and strength to plant tissues
What is Power to X?
Convert renewable electrical energy to X such as hydrogen, methane, methanol.
