BI374 – Phys. App. Of Microbiology
TA: Aaron Coristine
Student Name: Shane Thorn
Student ID: 161668950
January 30, 2017
Discussion Questions
General
1. Ammonification is the microbial degradation of nitrogenous compounds resulting in ammonia. Nitrification is a process by which ammonia is oxidized to nitrite and then nitrite is oxidized to nitrate. Denitrification is a process by which nitrate is converted into nitrogen gas or nitrous oxide by denitrifiers. Nitrogen fixation is a process by which atmospheric nitrogen is converted into ammonia by symbiotic or non-symbiotic mechanisms.
2. The distinguishing difference between the three types of soil used (cactus soil, peat moss, and all-purpose potting soil) is the diversity of microbes and nutrient content within each soil
3. …show more content…
Save for the negative control (as expected), denitrification had occurred in all samples. Samples containing P.aeruginosa, soil A and soil C were interpreted as positive for denitrification of nitrate to N2. This was observable by the presence of nitrogen gas in their respective Durham tube. Samples containing E. coli and soil B however, required additional testing against reagent A and reagent B as well as the introduction of zinc before determining if denitrification had occurred. Samples containing E.coli, and soil B were interpreted as having denitrification beyond nitrite
2. Cultures or soil samples that produced more gas than others did so because of the presence of nitrate reductase and nitrite reductase (produced by denitrifying microbes) in the sample.
3. The microscopically examined bacteria had one type of morphology and arrangement. In the soil types there was much more microbial diversity possessing a variety of morphology and arrangements.
4.
A. If nitrite is present, reagent A binds to nitrite forming a nitrite-sulfanilic acid complex. This complex then reacts with reagent B to produce a red precipitate – a positive result for nitrate
TA: Aaron Coristine
Student Name: Shane Thorn
Student ID: 161668950
January 30, 2017
Discussion Questions
General
1. Ammonification is the microbial degradation of nitrogenous compounds resulting in ammonia. Nitrification is a process by which ammonia is oxidized to nitrite and then nitrite is oxidized to nitrate. Denitrification is a process by which nitrate is converted into nitrogen gas or nitrous oxide by denitrifiers. Nitrogen fixation is a process by which atmospheric nitrogen is converted into ammonia by symbiotic or non-symbiotic mechanisms.
2. The distinguishing difference between the three types of soil used (cactus soil, peat moss, and all-purpose potting soil) is the diversity of microbes and nutrient content within each soil
3. …show more content…
Save for the negative control (as expected), denitrification had occurred in all samples. Samples containing P.aeruginosa, soil A and soil C were interpreted as positive for denitrification of nitrate to N2. This was observable by the presence of nitrogen gas in their respective Durham tube. Samples containing E. coli and soil B however, required additional testing against reagent A and reagent B as well as the introduction of zinc before determining if denitrification had occurred. Samples containing E.coli, and soil B were interpreted as having denitrification beyond nitrite
2. Cultures or soil samples that produced more gas than others did so because of the presence of nitrate reductase and nitrite reductase (produced by denitrifying microbes) in the sample.
3. The microscopically examined bacteria had one type of morphology and arrangement. In the soil types there was much more microbial diversity possessing a variety of morphology and arrangements.
4.
A. If nitrite is present, reagent A binds to nitrite forming a nitrite-sulfanilic acid complex. This complex then reacts with reagent B to produce a red precipitate – a positive result for nitrate