Topic 5

Question 1

Biodegredation

Answer 1

biologically catalyzed reduction of chemical complexity
-the breakdown of organic matter by microorganisms

-can be complete (mineralization) or partial

Question 2

Mineralization

Answer 2

-type of biodegredation
-when the biodegredation leads to the conversion of C, N P S and other elements in the original compound into inorganic products completely

Question 3

Biotransformation

Answer 3

the changing of a compiund to another reasonably stablemoleciule (one that is useful or less/more toxic that the original comppund,
often a simpler production

Question 4

What are the three stages to biodegredation

Answer 4

1) Biodeteriation: modifies physical, chemical and mechanical properities of the material
-occurs when exposed to ABIOTIC factors such as sunlight, heat,
-weakens the materials structure

2)Biofragmentation:
-bonds wihtin a polymer are cleaved (generating oligomers adn monomers)
-depends on oxygen availabiliy

3)Assimilation:
-products are assimilated into microbial biomass
-enter cells and products are used for ATP product and cell structures
-some products need to do biotransformatin before they enter cells

Question 5

what is more efficient, aerobic or anaerboic digestion

Answer 5

anaerobic

Question 6

What does compound degradeability depend on

Answer 6

-elemental composition
-structure of repeating units
-linkage between units
-degree of branching
-arrangement and type of substituents

Question 7

why is cellulose degredation slower and rarer than starch and glycogen

Answer 7

the linkage for cellulose is beta 1-4 whereas the other two ixs alpha 1-4, so the enzymes can break down the alpha easy but not the beta

Question 8

What are other compounds that microorganisms can degread, transform or accumulate

Answer 8

-hydrocarbons,
-PCBs (polychlorinated biphenyls)
-PAHs (polyaromatic hydrocarbons)
-radionuclies
heavy metals
-pesticides, herbicides and dyes

Question 9

what factors affect biodegradability

Answer 9

-ph tmeperature, organix matter content
-microorganisms consortium and whther its present
-bioavailabilit of target compound

Question 10

What makes some herbicides hard to break dow

Answer 10

-extra chloride grouo
(2,4,5-T vs 2,4D(no chloride)

Question 11

three levels to bioremediation

Answer 11

1) natural attenutation
2)biostimulation
3)bioaugmentation

Question 12

what is bioremidation

Answer 12

a process used to treate contaminated water, soil and or subsurface material, by altering the environmental conditions to stimulate the growth of microorganisms that will degrade a target pollutant

Question 13

what are the two classifications of hydrocarbons

Answer 13

aromatic or aliphatic

Question 14

what is the order of most easily degradeabe hydrocarbons to least

Answer 14

alkenes and short chained alkanes

branched alkanes
aromatics

up to 9 c: volatile, biodegradable, toxic
10 to 24 c: easily biodegradable
branching or more than 24: decreases biodegradeability
unsaturated (alkenes and alkynes, easily degradeable)

Question 15

what is degredation of hydrocarbons influenced by

Answer 15

o2 availability

it can occur aerobically by fungi and algae, and hoth aer and ana for bac and archaea but aerobically is better

most biodegredation is aerobic because o2 is direct reactant: OXYGENASE

Question 16

what are the steps for the aerobicx degredation of alkanes (aliphatics)

Answer 16

1) Oxygenase add oxygen to hydrocarbon, making it an alcohol
2) it is further oxidized into fatty acid
3) fatty acid is metabolized into acetyl co-A
4) used in TCA cycle

Question 17

What are the steps for the aerobic oxidation (biodegredation) of aromatics

Answer 17

1) Mono or di oxyfgenase adds oxygen to it
2) forms alcohol (phenol, benzyl alxohocol, catcehol)
3) these slcohols undergo ring cleavage, (by oxygenase) resulting in CARBOXYLIC ACIDS
4) degredation to acetyl coA and succinyl co-A
50 Used in krebs

Question 18

what is the main difference for anaerobic biodegredation

Answer 18

1) multistep process is needed to create methane and co2 as the end produ t since methanogens can only use h2 and acetate so they neede primary fermenters to break it down initially so it is a syntrophy, cant just occur with one set of microbes
2)different e- acceptors are used since o2 cant be, tbhey are used in decreasing reduced potential order so Oxygen, nitrate, co2, sulfate and h2