Microbial Ecology Flashcards
What are biochemical cycles?
The movement of chemical elements through the biological and geological world
What do bacteria do in recycling?
Break down chemical substances into simpler compounds or elements.
What is mineralization?
conversion of organic matter to minerals and other inorganic materials.
What are the major elements of bacteria?
C,N,S,P,O,and H.
What are the minor elements of bacteria?
Mg K Na
What are trace elements of Bacteria?
Al Cu Zn
What is the most important element in the biosphere?
carbon
Where is the earth’s carbon stored?
as fossil fuels, coal, peat, oil and natural gas.
What is the carbon source?
carbon dioxide , from photosynthesis and waste product of respiration
What is carbon transformation/
Primary producers fix carbon dioxide, including plants, algae, cyanobacteria, phototropic bacteria
How is fized carbon returned to the atmosphere?
as CO2, in one of 3 ways, respiration, food for herbivores and carnivores, decomposition of dead tissues.
What are types of primary producers?
Photoautotrophic , Chemoautotrophic, Heterotrophic, Methanogen
What is a photoautotrophic bacteria?
Photoautotrophic bacteria fix CO2 via the Calvin cycle and by a reversal of the TCA cycle. This reversal of the TCA cycle occurs in the Green sulfur bacteria
What is a chemoautotrophic bacteria?
Chemoautotrophic bacteria, derive their energy from the oxidation of chemical compounds, NH3, CH4, H2S. Small % of CO2 fixation.
What is a heterotrophic bacteria?
Heterotrophic CO2 fixation, synthesis of the intermediates of the TCA cycle
What is a methanogens bacteria?
Methanogens, reduce CO2 to CH4. This occurs via several steps
What are herbivores and carnivores?
Herbivores consume organic material formed from CO2 fixation, and then become food sources for carnivores.
How is cellulose decomposed?
Cellulose is hydrolyzed to glucose. Plant cell wall cellulose degraded by many different types of bacteria. Breakdown of the beta 1,4 linkages, Rumen stomach.
How is chitin decomposed?
Chitin, poly N-acetlyglucosamine, found in insect exoskeleton, hydrolyzed by chitanases mainly Streptomyces.
How is synthetic carbon compounds decomposed?
Synthetic carbon compounds degraded by specialized bacteria, ie Pseudomonads
What is the most abundant gas in the earth’s atmosphere?
nitrogen
How much is nitrogen is cycled each year?
Each yr 1 billion tons of nitrogen is transformed by the N cycle.
WHat does the biogeochemical recycling of nitrogen require?
microbial activities in 4 stages
What is the first stage of N cycle?
Nitrogen fixation
How is nitrogen fixation completed?
N2 has triple bonds, hard to break. Done symbiotically via certain bacteria, ie, Rhizobium, Bradyrhizobium. Non symbiotically the bacteria involved include, Klebsiella, Chromatium. Needs a lot of ATP to accomplish the reaction.
How is ammonification completed?
Ammonification, Nitrogen taken up by bacteria is converted into proteins, nucleic acids, therefore it must be decomposed into ammonia, example urea into ammonia.
How is nitrification completed?
Nitrification, ammonia is oxidized into nitrate. 2 steps involved, ammonia into nitrite, nitrosofying bacteria. Then nitrite converted into nitrate, nitrifying bacteria.
How is denitrification completed?
Denitrification, is the formation of N2, as well as NO and N2O from nitrite or nitrate. Pseudomonads most common denitrifier, nitrate reductase.
What is the phosphate cycle?
Important in living cells, ie ATP, high E bonds. Microbes solubilize phosphate salts as part of this cycle
What is the sulfur cycle?
Sulfur is widely distributed in nature. Fossil fuels, rocks and sulfur deposits. It occurs in 3 states, S0, S-2, and SO4-2.
What bacteria convert sulfur?
Beggiatoa, Thiothrix, convert sulfide into elemental sulfur.
Thiobacillus, converts elemental sulfur and sulfides into sulfate.
Where are sulfates used?
Sulfates formed can be assimilated into cellular proteins or reduced to hydrogen sulfides . Desulfovibrio, is able to demonstrate dissimilatory sulfate reduction to sulfide.
How do sulfates form?
Sulfates also form from the anaerobic oxidation of sulfides and thiosulfates by green and purple phototropic bacteria.
Why are microbes found in the soil?
Microbes found in high #’s in the soil. Their numbers vary with the depth. Many have diverse metabolisms. Good habitat for their cultivation. Their presence depends on the substrates present for their cultivation.
What are types of metals bacteria leach?
Leaching is used to extract copper, lead, zinc and uranium from sulfide containing ores.
What are the bacteria involved in ore leaching?
Thiobacillus ferrooxidans, T. thiooxidans. T. ferrooxidans
What do they obtain from the ore?
carbon from carbon dioxide and its E from the oxidation of either iron or sulfur, elemental sulfur, sulfides, and thiosulfate
What are commercial scale operations of ore leaching?
Commercial scale operations crushed low grade copper, containing T. ferrooxidans, sprayed with dilute sulfuric acid and oxidizes CuS in the ore
What are hydrocarbon degarding bacteria?
Pseudomonas. Used to clean up soil that has been contaminated with toxic hydrocarbons, ie petroleum based
What are microbial biopesticides?
Used to replace chemicals that are sprayed on the soil that are difficult to degrade or harmful to the environment
What microbes are in the marine environment?
In the coastal region, pseudomonads, vibrio and flavobacterium are important. Vibrio parahaemolyticus and V. vulnificus are very important. In the marine environment, pH is 8.3 to 8.5, salinity is 0.5 to 2.5%.
WHere are microbes in fresh water?
In the fresh water environment, many heterotrophic bacteria, pollution and sewage runoff can influence water quality dramatically. Seasonal changes influence microbial flora.
How much of the worlds water is potable?
Less than 2% of the world’s water is potable, suitable for drinking
How much water is used in the US daily?
Each day the US uses 25 billion gallons of water. Small portion is used for drinking, all of it eventually becomes sewage
What is BOD?
BOD, biochemical oxygen demand, is defined as the quantity of oxygen required to meet the metabolic demands of microbes oxidizing the organic matter in the water.
How is BOD tested?
Done as a lab test over 5 days at 20 C, in a sealed container. Water if the initial BOD is 300ppm after treatment it should be reduced to <30ppm in sewage treatment
How is sewage quality measured?
BOD and COD
What are indicator bacteria?
These bacteria are used to monitor water quality. Pathogens are usually in low numbers, therefore coliforms are used to monitor water quality. MPN and MF tests are ways to monitor water for coliforms
How many stages are there in sewage treatment?
primary, secondary and tertiary
What is the primary sewage treatment stage?
removal of suspended solids and floating materials
What is the secondary sewage treatment stage?
biological agents are used to purify the sewage
What is the tertiary sewage treatment stage?
additional purification, filtration , chlorination
