Lecture 271. Know how carbon enters and leaves living systems and which pathways occur aerobically or anaerobically a. Carbon enters living systems by CO2 fixation by photoautotrophs and chemolithotrophs, leaves by organisms using CO2 as energyb. Aerobic respiration- results in conversion back to CO2c. Acetogens and methanogens can utilize CO2 for energy productiond. Anaerobic respiration and fermentation convert organic matter back to CO22. Explain the concepts of secondary fermentation and syntrophy a. Secondary fermentationsi. Utilize the products of primary fermenters (CO2 + H2 and simple organic acids) for further fermentationsii. Secondary fermenters and methanogens/acetogens are examples of syntrophy 3. Be able to state what happens in the nitrification, denitrification, and anammox pathways a. Nitrogen fixation- Brings atmospheric N2 into living systems b. Dentirification and anammox returns N2 into the atmosphere 4. Know the formulas of ammonium, nitrite, nitrate a. Ammonium- NH4+b. Nitrite- NO2 -c. Nitrate- NO3-5. Explain how N2 enters living systems a. Nitrogen fixation6. Explain how spreading of nutrients and microbes is useful for cleaning petroleum spills a. Some microbes are able to metabolize compounds that are toxic to animals and humans and degrade or transform them to safer chemicals b. Many microbes metabolize various components of petroleum and oxidize them to CO2: some produce extracellular surfactants and emulsifying agents7. Know what xenobiotics are and how microbes can be utilized for bioremediation a. Xenobiotics are synthetic compounds (for example chlorine containing pesticides and herbicides) not produced by living organismsb. Used in dechlorination which is an important step in bioremediation of these chlorine containing organic pollutants by microbes8. Know what happens in each of the three stages of wastewater treatment a. Primary- remove solidsb. Seconday- use microns and use aerobic and anaerobic processing c. Tertiary – use microbes and chemicals 9. Understand what happens during the aerobic activated sludge process andwhy slime-producing microbes are important a. Activated sludge method uses aeration tanks or lagoons to promote growth of microbial community so pathogens are brokendown and converted into harmless microbial biomass b. A managed microbial community grown in a designed habitatc. Slime producing create large flocs aggregations of microbes that will settle outing the settling tankd. The settles flocs produce a concentrated microbial community know as activated sludge 10. Explain how and why anaerobic treatment is performed a. Done in an enclosed vessel, where much of the solid organic matter is converted into gas fermentation products b. A community of anaerobes decompose organic products from aerobic processing into gas products and harmless cell biomassi. Methanogens produce methane and water 11. Provide an examples of tertiary treatment to remove remaining nutrients from treated wastewater a. Tertiary wastewater treatments is to reduce the levels of nutrients in the released water to a minimum b. After secondary treatments wastewater can contain various nitrogen compounds, phosphorus and other organics that should be removed i. Phosphorus can be removed by biological methods using phosphate accumulating microbes by a process known as enhanced biological phosphorus removal. 12. Provide examples of how municipal water can be disinfected and treated toprevent and kill pathogens a. Physical and chemical purification steps must be taken to make municipal water suitab;e for human consumption. Untreated water goes through several steps:i. Sediment removalii. Addition of clarifier chemicals followed by filtration to remove particlesiii. Disinfection to kill remaining microbes and prevent growth1. A long lasting form of chlorine is added to persist in distribution system: usually chloramine (NH2Cl)2. Sometimes UV light is also
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