Concept explainers
Videos
To review:
The bacteria appropriate for reducing nitrate concentration found in a sample of municipal sewage water.
Introduction:
Nitrates refer to the essential source of nitrogen for the plants. Nitrification is basically the biological oxidation of the ammonium or ammonia to nitrite, which is followed by the oxidation of the nitrite to nitrate. This transformation of ammonia to nitrite is generally the rate-limiting step of the nitrification. Whereas, denitrification refers to the loss or the removal of the nitrogen and compounds of nitrogen. Many bacteria help in this process of denitrification.
The table given below gives details of characteristics of four bacteria:
| Name of Bacteria | Clostridium novyi | Thermus aquaticus | Paracoccus denitrificans | Trichodesmium thiebautii |
| Characteristics | ||||
| Obligate anaerobic | Obligate aerobic | Facultative anaerobic | Facultative anaerobic | |
| Gram status | + | – | – | – |
| Optimal temperature (°C) | 10–40 | 50–80 | 5–30 | 10–30 |
| Typical habitat | Terrestrial | Aquatic | Aquatic | Aquatic |
| Miscellaneous | Chemotroph | Denitrifier | Nitrogen fixer |
°C, Degree Celsius; (+), positive, (–), negative.
Explanation of Solution
According to the given statement, concentration of nitrate in municipal sewage water is very high, which is beyond the acceptable level. High concentration of nitrates can be reduced by the process of denitrification. This process is facilitated by denitrifying bacteria.
The facultative anaerobic bacteria Paracoccus denitrificans is the most appropriate bacteria for reducing nitrate concentration. In the process of denitrification, the bacterium reduces the nitrate to produce molecular nitrogen. This process is usually used in to reduce nitrate or nitrite concentration from sewage water.
Paracoccus denitrificans is a denitrifying bacterium and can survive in both organic and inorganic media. This bacterium performs the process of denitrification as a part of respiration, in which the nitrate is reduced in response to oxidation of an electron donor and finally the denitrification completed with the production of dinitrogen. During reducing nitrate, the bacteria produce intermediate products.
Therefore, it can be concluded that Paracoccus denitrificans is used to reduce the concentration of nitrates from the municipal sewage water. This bacterium is a facultative anaerobic organism and also a denitrifier.
Want to see more full solutions like this?
Chapter 25 Solutions
Life: The Science of Biology
- Diseases that involve biofilm-producing bacteria are serious concern. They are not easily treated compared with those involving free-floating bacteria. Explain three reasons why biofilm formers are more pathogenic.arrow_forwardWhich of the following types of bacteria can contaminate water sources in hospitals and also cause pulmonary diseases or infections? Question 9 options: Mycobacterium spp. Hydrobacterium spp. Escherichia coli Shigella spp.arrow_forwardThe following plates were inoculated with organisms A, B, C, and D on each sector of this plate. Each plate was grown at the the temperature indicated (4C, 25C, 40C, and 60C). Choose the organism that is the psychrophile. A B D Carrow_forward
- Diseases that involve biofilm-producing bacteria are of serious concern. They are not as easily treated compared with those involving free-floating (or planktonic) bacteria. Explain three reasons why biofilms can be more pathogenic.arrow_forwardd) Since we know this bacterial organism thrives in colder areas of the world, what can be said about the effect of temperature on the growth patterns ofthis bacterial organism? How would increasing the temperature affect the growth constant? e) If the bacterial organism is resistant to antibiotics, how would administering antibiotics affect the growth of this organism?arrow_forwardFlasks A and B contain broth, and are inoculated with an identical number of bacteria that are facultative anaerobes. Flask A contains a triglyceride lipid as the sole nutrient source, and Flask B contains a monosaccharide called fructose as the sole nutrient source. Both flasks are incubated at 30°C with aeration (oxygen is added to the broth). Assume the bacteria are capable of catabolism of both fructose and triglycerides. Mark all the correct statements pertaining to these cultures. A. Under anaerobic conditions, cells in flask A will produce more ATP B. Cells from flask B will produce more carbon dioxide C. Cells from flask B will produce more ATP D. Flask A will have the greater cell mass E. Cells from flask A will produce more ATP F. Cells from flask A will produce more carbon dioxide G. Flask B will have the greater cell mass H. Under anaerobic conditions, cells in flask B will produce more ATParrow_forward
- Which of the following is correct about biofilms? O 1) They are comprised only of psychrophiles. O 2) They are more sensitive to changes in growth conditions than planktonic cells O 3) Quorum sensing allows the biofilm community to behave differently than planktonic organisms 4) Biofilms only form within the environment. 5) Pure cultures are necessary for biofilm formation.arrow_forwardGive an example of a bacterium that can be described as an “anaerobic chemoorganoheterotroph ”. Also explain what the different parts of the description meanarrow_forwardRefer to the following graph of Carbon Assimilation vs. Irradiance of several cultures of dinoflagellates in the northern Baltic Sea. Samples were treated with varying levels of pH. What is the effect of pH on the metabolism of the cultures? a) The growth of the culture is limited by increasing pH. b) The growth of the culture is increased by increasing pH. c) The growth of the culture is not limited by increasing pH. d) The growth of the culture is not affected by increasing pH or increasing irradiation.arrow_forward
- A microbiologist identifies a bacterium that is capable of degrading cellulose, lignin, chitin, latex, aromatic chemicals, and keratin. It produces metabolic byproducts that give soil a musty smell as well as some that can be used as antibiotics. Which of the following genera is being described? View Available Hint(s) for Part A Pseudomonas Campylobacter Neisseria Streptomycesarrow_forwardListen Which of the following regarding controlling microbial growth is true? a) Microbial death rate increases with an increase in temperature b) The more microbes present, the shorter amount of time it will take to kill the population E c) Gram-positive bacteria tend to be more resistant to chemicals than gram- negative bacteria d) Microbial death rate increases as pH approaches 7 (neutral) Previous Page Submit Quiz $ R Next Page 5 of 10 questions saved % H K Page 4 of 10arrow_forwardIdentify the genus that best fits each of the following descriptions: a. This organism can produce a fuel used for home heating and for generating electricity. b. This gram-positive genus presents the greatest source of bacterial damage to the beekeeping industry. c. This gram-positive rod is used in dairy fermentations. d. This gammaproteobacterial genus is well suited to degrade hydrocarbons in an oil spill.arrow_forward
