Lecture 8 Whyte Flashcards
T or F: The number of marine oil spills have been increasing due to increased shipping and transport of fuels
T
The sources of oil released into the oceans is estimated at:
5x10^6 tonnes/year
What are natural sources of marine oil spills?
The gulf of mexico is a huge reservoir of oil. Microbes present have many ions available to degrade hydrocarbon sources
In the Ocean hydrocarbon cycle, hydrocarbon degrading bacteria use _________ as an energy source and produce ________
alkanes
CO2
The conversion of CO2 to alkanes uses energy derived from _________________
photosynthesis
Complete the following: ALKANES - FATTY ACIDS -
TCA CYCLE
RESPIRATION
Complete the following: CO2 - SUGARS -
ACYL-ACPs
ALKANES
Alcanivorax borkumensis is an obligate _____________________ bacterium
hydrocarbonoclastic
Alcanivorax borkumensis plays a significant role in the biological removal of ____________________________
petroleum hydrocarbons from polluted oceans
T or F: Alcanivorax borkumensis relies solely on eating hydrocarbons as an energy source
T
Alcanivorax secretes natural _____________ which help to break up oil droplets
emulsifiers
The genome of alkalivorax borkumensis has metabolic pathways to degraden________
alkanes
Name some things that Alcanuvorax borkumensis has in its genome sequence:
- Alkane
- Biosurfactant
- Nitrate
- Phosphate
- TonB-dependent receptor (sequester iron because oceans are iron-depleted
Why is it beneficial when there’s a storm going on at the same time during an oil spill?
Because the wave action will emulsify the oil and breaking it down into the water column, smaller and smaller droplets and some microorganisms in the ocean will eat those hydrocarbons
List some remediation treatment options for marine oil spills:
- In-situ burning
- dispersants
- photooxidation
- evaporation / aerosolization
- emulsification
T or F: The exxon Valdez oil spill happened in 1989 and caused some significant ecosystem damage both in the short and long term
T
How did they try to remediate the exxon valdez oil spill?
- mechanical clean up (boomers and skimmers , flotation devices to keep the slick at one place)
- washing of beaches
- dispersants (Corexit) in seawater
- burning in seawater
Explain how they tried to clean the beaches in the exxon valdez oil spill:
- they did physical washing of shorelines with high pressure water
- application of fertilizer for bioremediation
What are the 2 major steps necessary when attempting to maximize the cleaning of a beach covered with crude oil:
1) Clean up the bulk of the oil by physical means
2) Clean up the remaining oil via in situ bioremediation: done only as a limited trial with EVOS
What are some compounds/fertilizers added to stimulate biodegradation of crude oil on beaches:
1) Inipol EAP 22 (360g/m^2)
2) Customblen (17g/m^2)
What compound has the following characteristics:
- oleic acid: surfactant
- urea: N & C source
- tr(laureth-4)-phosphate: detergent, P source
- 2-butoxyethanol: solvent
- Oleophilic, slow release fertilizer
Inipol EAP 22
What compound has the following characteristics:
- Ammonium nitrate: N source, NO3 can act as terminal electron acceptor in anaerobic zones
- Ammonium phosphate: N & P source
- Calcium phosphate: P source (water soluble it all washes out)
- No microbes were added (natural population was stimulated)
Customblen
How do you know that bioremediation approach was successful?
1) quantify residual oil contamination per area and by type of hydrocarbon, over time
2) look for enhanced population of hydrocarbon degraders at treated sites using molecular genetic methods
3) expect to find increased rate of biodegradation of crude oil constituents in sediments isolated from treated compared to untreated areas
How do you test for biodegradation rate:
- mix equal quantities of sediment slurry from treated and reference areas with C14 labeled hexadecane or phenanthrene in test bottles
- hexadecane is a n-C16 straight chain alkane often used as a model alkane in biodegradation studies
- phenanthrene is a 3-ring PAH often used as a model PAH in biodegradation studies
- compare the rate of 14CO2 produced over time and in T and R sediments
T or F: The EVOS environment is enriched with hydrocarbon-degrading bacteria
T
Gene probe analyses probed EVOS bacterial isolates for presence of genes known to be important for biodegradation of hydrocarbons:
______ gene encodes catechol 2,3-dioxygenase, a gene commonly used as a probe to detect bacteria that have the capacity to grow on aromatic compounds (whether from petroleum hydrocarbons or other origins).
______ gene encodes alkane hydroxylase, a gene commonly used as a probe to detect bacteria that have the capacity to grow on C6-C12 alkane compounds
xylE
alkB
Weathered oil lacks _________ and has less of the easily biodegraded compounds (generally lower molecular weight)
volatiles
- 779 million liters
- light louisiana oil
- well leak with uncertain flow rates, large amounts of methane also released
- discharged at well head in 1500m of seawater
- 77km offshore
- impacted deep-sea cloud of fine droplets of low concentration oil, marshes and sandy beach shorelines, 84 days to stop leak
- aerial and subsurface dispersants used extensively
- fate of oil remnants yet to be determined
- largest remediation and emergency response to an oil spill ever, worldwide
BP Deepwater Horizon
- 41.6 million liters
- north slope heavy oil
- tanker spill with known volume
- discharged as surface spill
- on Bligh (near island shorelines)
- impacted cobble/rocky shorelines, major storm 50mph winds 2 days after the spill
- bioremediation used extensively
- fate of oil remnants still studied more then 21 years after spill
- much scientific and operating experience gained / is applicable to other spills
Exxon Valdez oil spill
Metagenomics in bioremediation =
sequencing of all the DNA from a polluted environmental sample and then looking for biodegradative genes and pathways of interest
Metagenomics is now sometimes done in parallel with ______________ + ______________
metatranscriptomics
metaproteomics
isolate all mRNAs from an envrionmental sample, convert to complementary DNA (cDNA), sequence, compare to metagenome, indicates which genes are being transcribed ie coming from active microorganisms
metatranscriptomics
isolate all proteins from an environmental sample, sequence, compare to metagenome, indicates which genes are being transcribed/translate ie really active =
metaproteomics
DNA (TRANSCRIPTION) = mRNA (TRANSLATION) = Nascent protein :
central dogma of life
T or F: Plastics are manufactured products from hydrocarbons, they are very recalcitrant to biodegradation
T
T or F: PET and PEF are considered biodegradable plastics due to the ester bond C-O in their structure
T
PET =
Polyethylene terephthalate
hydrolytic enzymes such as ___________ are reported to degrade polymers such as PET in vitro
cutinases
T or F: there are no example of the complete mineralization of PET
T
Polymers such as bio-based polyhydroxyalkanoates (PHAs) and polylactic acid (PLA) , and oil-based polycaprolactone (PCL) can be completely _________________ by the activity of microorganisms
mineralized
Can you use protein engineering to create better plastic degrading enzymes?
yes
