Lecture 3 Whyte

Question 1

Name an example of an organic pollutant:

Answer 1

hydrocarbon (C-H bonds)

Question 2

Name an inorganic pollutant:

Answer 2

mercury/metals/heavy metals

Question 3

Why are most organic pollutant better degraded aerobically?

Answer 3

Because the process is faster and more complete oxidation to CO2. This is important for bioremediation because you’re reducing the amount of contaminant in the environment more quickly, therefore it becomes less toxic

Question 4

T or F: Anaerobic degradation steps are also very important in the biodegradation of some pollutants

Answer 4

T

Question 5

T or F: Pollutant biodegradation is not limited by O2 as long as there is an alternative terminal electron acceptor and lots of it!

Answer 5

T

Question 6

What are some examples of anaerobic systems within out bodies:

Answer 6

• muscles

- GI tract

Question 7

What bacteria can function well in an anaerobic environement:

Answer 7

• SRB

- methanogens

Question 8

Why is the middle of a soil aggregate anaerobic?

Answer 8

Because the bugs in the middle are metabolizing all the available oxygen faster than the rate of diffusion in the soil aggregate

Question 9

The soil environment is a ______________ microbial habitat!

Answer 9

heterogenous

Question 10

The soil contains both ____________ and ___________ zones, varies greatly, even within a soil aggregate

Answer 10

aerobic

anaerobic

Question 11

T or F: O2 concentration decreases with depth in a soil

Answer 11

T

Question 12

O2 concentration decreases towards the center of a soil particle due to diffusion, and utilization of O2 on the _________ (before it can diffuse in)

Answer 12

surface

Question 13

Different terminal electron acceptors are available in different ______ and the availability of the terminal electron acceptors differs with ______

Answer 13

niches

depth

Question 14

Many organisms utilize metallic terminal electron acceptors (ie., ________________________), which also vary with depth

Answer 14

MnO2

Fe(OH)3

Question 15

T or F: Some organisms may only be able to utilize one compound as their electron acceptor whereas others may be able to utilize more than one, but usually from adjacent zones only

Answer 15

T

Question 16

What is anaerobic respiration?

Answer 16

When electrons are transferred to compounds other than O2

Question 17

Give the name of these 2 compounds:

• NO3
• SO4

Answer 17

• nitrate

- sulfate

Question 18

Reduction of the terminal electron acceptor may occur in _________ rather than cytoplasm but the effect is the same

Answer 18

periplasm

Question 19

Some organic compounds may serve as terminal electron acceptors in anaerobic respiration such as:

Answer 19

• fumarate to succinate via fumarate reductase

- transfer of electrons to CO2 yielding waste (CH4)

Question 20

Electron donor is the one that gets _______________

Answer 20

oxidized

Question 21

Denitrifiers use _____ as a terminal electron acceptor and reduce it to gaseous product such as _____ and ___.

Answer 21

NO3-
N2O
N2

Question 22

A great variety of bacteria are denitrifiers. The most abundant in soil are _________ and ___________

Answer 22

Pseudomonas

Alcaligenes

Question 23

__________________ and _________________ are toluene degrading bacteria under anaerobic conditions

Answer 23

Thauera aromatica

Azoarcus tolulyticus

Question 24

Iron-reducing and manganese-reducing bacteria are little known bacteria that can use iron or manganese as terminal electron acceptor in the oxidation process of ______________

Answer 24

organic matter

Question 25

A Fe-reducing bacterium degrading toluene under anoxic conditions was recently isolated:

Answer 25

Geobacter metallireducens GS15

Question 26

H2S (hydrogen sulfide) smells like:

Answer 26

rotten eggs

Question 27

________________ use sulfate as the terminal electron acceptor and are very useful in biodegradation/bioremediation of wastewater treatment plant

Answer 27

sulfate-reducing bacteria

Question 28

T or F: sulfate-reducing bacteria are strict anaerobes and use sulfate as terminal electron acceptor

Answer 28

T

Question 29

_________________ are strict anaerobes that use CO2 as electron acceptor with H2 as energy and electron source or ferment acetate. these are important bacteria for a number of environmental problems related to atmospheric trace gases, but they are also intensely studied since they have been implicated in the anaerobic degradation of toluene in sediment or activated sludge reactors

Answer 29

methanogenic archaea

Question 30

Fermenters use ______________ as a terminal electron acceptor

Answer 30

organic molecules

Question 31

Clostridium are a good example of _________________ found in soil

Answer 31

fermenting bacteria

Question 32

Why is Shewanella oneidensis a super microbe:

Answer 32

because it can use a wide variety of electron acceptors

Question 33

Mercury has tendency to concentrate in ___________________ and is highly toxic

Answer 33

living tissues

Question 34

The major form of mercury in the atmosphere is elemental mercury (Hg0), which is volatile and oxidized to mercuric ion (Hg2+) ______________

Answer 34

photochemically

Question 35

Most mercury enters aquatic environments as ______

Answer 35

Hg2+

Question 36

Under anaerobic conditions, microorganisms transform Hg2+ into ____________________, an extremely soluble and toxic compound

Answer 36

methylmercury (CH3HG+)

Question 37

T or F: Several bacteria can also transform toxic methylmercury to nontoxic forms, which is being explored to bioremediate Hg contaminated sites

Answer 37

T

Question 38

Hg methylation is an _________________ process

Answer 38

anaerobic

Question 39

Hg demethylation is an __________________ process

Answer 39

anaerobic and aerobic

Question 40

T or F: Most pathogenic bacteria are heterotrophs and use organic carbon as their energy source

Answer 40

T

Question 41

To define microbial nutritional categories we need to ask the following questions:

Answer 41

- What is the source of energy - What is the source of electrons - What is the source of carbon

Question 42

Photoautotrophs get their energy source from __________ and carbon source from ________ * most cyanobacteria

Answer 42

light | CO2

Question 43

Chemoheterotrophs get their energy and carbon source from:

Answer 43

organic compounds

Question 44

Chemolithoatutotrophs get their energy from _______________ and their carbon from _________

Answer 44

- inorganic compounds | - CO2

Question 45

What types of pollutants would be biodegraded by heterotrophic microorganisms?

Answer 45

Any type of pollutant that contains organic carbon, could probably be assimilated and biodegraded by heterotrophic microorganisms because they get their energy from carbons

Question 46

Bacteria able to oxidize reduced inorganic compounds such as NH4+, H2S, or H2 to synthesize ATP for biosynthesis and fix CO2

Answer 46

Chemolitoautotrophs

Question 47

________________ use NH4+ as sole energy source and oxiddize it to NO2-, these bacteria present some interests in the context of bioremediation since they have a monooxygenase which may attack some pollutants usch as TCE

Answer 47

Ammonia-oxidizing nitrfying bacteria

Question 48

________________________(Nitrobacter) use NO2- as sole energy source and oxidize it to NO3-

Answer 48

Nitrite-oxidizing nitrifying bacteria

Question 49

Environmental systems like soil or sediment are not ____________

Answer 49

homogenous

Question 50

Do the order of the 4 best electron acceptors in marine or fresh water system overlaying sediments:

Answer 50

- Oxygen respiration - NO3- - SO4 2- - CO2

Question 51

A profile of sediment shows that after the depletion of O2, NO3- is depleted and then depletion of SO4 2- results in _________________. Finally, the utilization of CO2 results in _____________________ as ll the other potential electron acceptors have been depleted

Answer 51

- sulfide accumulation | - CH4 accumulation

Question 52

Give an example of a reduced organic compounds

Answer 52

carbohydrates, CH4

Question 53

Give an example of a reduced inorganic compounds

Answer 53

H2S, Fe2+

Question 54

Need to energize the ______________________ via proton gradient

Answer 54

cytoplasmic membrane

Question 55

Proton gradient powers the production of:

Answer 55

ATP, NADPH

Question 56

The _______________ of NADPH are required for some biochemical reactions

Answer 56

reducing powers