Biodegradation of Petroleum Hydrocarbons By: Sheikh Amir Hamza. 256-FBAS-BSBT-F12
Aug 11, 2015
Biodegradation of Petroleum Hydrocarbons
By: Sheikh Amir Hamza.256-FBAS-BSBT-F12
What are petrochemicals?
Chemicals derived from petroleum or natural gas.
Major petrochemicals are acetylene, benzene, ethane, ethylene, methane, propane, and hydrogen.
A huge variety of products are made with petrochemicals.
Including plastics, soaps, pharmaceuticals, fertilizers, pesticides, detergents.
Molecular structures of hydrocarbons.
Cons of Hydrocarbons
HCS belong to the family of carcinogens and neurotoxic organic pollutants.
Main cause of water and soil pollution.Accumulation of pollutants in living cells
may cause death or mutations.Their removal is necessary.
Microbial Degradation of Petroleum Hydrocarbons
Biodegradation of HCS is a complex process depending on:the nature Amount of the hydrocarbons presentPetroleum HCS divided into four classes:The alephaticsThe aromaticsThe asphaltenes (phenols, fatty acids, ketones,
esters, and porphyrins), And the resins (pyridines, quinolines, carbazoles,
sulfoxides, and amides
Approaches In HC’s Degradation
Bioaugmentation:It is the introduction of biodegrading microbes at the site of spill to aid the indigenous microbial species.
Biostimulation:In Biostimulation nutrients and growth limiting factors are added to soil indigenous microbes.
Natural mechanism for degrading HCS
by bacteria, yeast, and fungi.Mix population of these microbes are
more efficient.Bacteria are the most active agents in
petroleum degradation.
Enzymes and microbes Participating in Degradation of HCS
Enzymes Substrates Microorganisms References
Soluble MethaneMonooxygenases
C1–C8 alkanes alkenes and cycloalkanes
Methylococcus
Methylomonas
McDonald et al.
Particulate MethaneMonooxygenases
C1–C5 (halogenated) alkanes and cycloalkanes
Methylobacter
Methylococcus
McDonald et al.
AlkB relatedAlkaneHydroxylases
C5–C16 alkanes, fatty acids, alkyl benzenes, cycloalkanes
Pseudomonas
BurkholderiaRhodococcusMycobacterium
Jan et al.
Eukaryotic P450 C10–C16 alkanes, fatty acids
Candida maltosa
Candida tropicalisYarrowia lipolytica
Iida et al
Bacterial P450oxygenase system
C5–C16 alkanes, cycloalkanes
CaulobacterMycobacterium
Iida et al
Dioxygenases C10–C30 alkanes Acinetobacter sp.
Maeng et al
Mechanism of Petroleum HCS Degradation
Mechanism of Petroleum HCS Degradation
Biosynthesis of cell biomass occurs from the central precursor metabolites, for example,
acetyl-CoA, succinate, pyruvate. Other mechanisms are
Attachment of microbial cells to the substrates.
Production of biosurfactsants.
Biodegradation of Petroleum compounds
Petroleum compounds are categorized into 2 groups
Aliphatic hydrocarbon e.g. alkane, alcohol, aldehyde
Aromatic hydrocarbon e.g. benzene, phenol, toluene, catechol
Straight chain Aliphatic Hydrocarbons
Cyclic Aromatic Hydrocarbons
Anaerobic degradation
Under nitrate-reducing bacteria
Sulfate-reducing bacteria
Factors Influencing Petroleum HCS Degradation
A number of limiting factors affect the biodegradation of petroleum HCSChemistry of HCSPhysiological factorsNutrients
Temperature Range
Conclusion
Cleaning up of petroleum HCS is a real world problem.
It depends on the indigenous microorganisms to transform or mineralize the organic contaminants.
Microbial degradation process aids the elimination of spilled oil from the environment after critical removal of large amounts of the oil by various physical and chemical methods.
This is possible because microorganisms have enzyme systems to degrade and utilize different hydrocarbons as a source of carbon and energy.
Therefore, based on the present review, it may be concluded that microbial degradation can be considered as a key component in the cleanup strategy for petroleum hydrocarbon remediation
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