In this presentation, I discussed the aliphatic degradation of the aromatic compounds by aerobic pathway

1. BY
BOOBASH RAJ S
VI M.TECH
DEPT OF BIOTECHNOLOGY
AEROBIC DEGRADATION OF
ALIPHATIC COMPOUND

2. AEROBIC DEGRADATION
 Aerobic biodegradation is the breakdown of organic pollutants by microorganism when
oxygen is present
 Organic contaminants are rapidly degraded under aerobic condition by aerobic bacteria called
aerobes
 Various bacteria mainly Actinobacteria and Proteobacteria are capable of aerobic estrogen
degradation
Microbes Chemicals
Pseudomonas, Arthobacter Hydrocarbons
Candida, Alcaligenes PolyChlorinated biphenyl
Flavobacterium, Aspergillus Phenolics
Nocardia PAH

3. HYDROCARBONS:
The hydrocarbons are broadly classified into two compounds
ALIPHATIC COMPOUNDS:
 It is a chemical compound belonging to the organic class in which the atoms are connected by
single, double, triple bonds to form non-aromatic structure.
Hydro compounds
Aromatic compounds
Aliphatic compounds

4. Types Of Aliphatic Compound:
Examples Of Aliphatic Compound:
Ethylene, isooctane, acetylene, propene, propane, squalene, and polyethylene

5. Aliphatic Compounds Based On Molecular Weight
 The gaseous alkanes
 Lower molecular weight (C8–C16)
 Medium molecular weight (C17–C28)
 High molecular weight (>C28)
Long-chain alkanes are first enzymatically activated before degradation

6. Mechanism Of Aliphatic Compound Degradation By Aero

7. Uptake of Hydrocarbons into
Microbial Cells
 Microorganisms are challenged by the hydrophobicity and insolubility of hydrocarbons
 Changes depends on the type of hydrocarbons and their carbon chain length and include changes
from cis-to-trans isomers.
 For example: C2–C4 alcohols increase the ratio of unsaturated fatty acid in cell membrane,
longer alkanols induce the production of saturated fatty acids.
 These limitations can be resolved using microdroplets, macrodroplets or dissolution of the
hydrocarbon molecules into water.
 Due to the difficulty of solubilization and the slow dissolution HMW is lower when compared to
LMW.
 At a concentration of higher than 4.54 μmol/L, Pseudomonas sp.

8. List Of Enzymes Involved In Degradation Of
Aliphatic Compounds
Enzymes Chain Length
Methane monooxygenases C1–C4
Alkane monooxygenases C5–C16
Bacterial P450 (CY153, class I) C5–C16
Eukaryotic P450 (CYP52, class II) C10–C16
Dioxygenases C10–C30

9. The monooxygenases isolated in prokaryotes are classified
into two categories
 A rubredoxin-dependent enzyme (containing 2FeO), encoded by the gene alkB in most of
bacteria and alkM in Acinetobacter sp.,
 An alkane hydroxylase containing cytochrome P450 monooxygenases in the CYP153 family of
bacteria.
 The first enzyme isolated was a non-heme diiron monooxygenase alkane hydroxylase located in
the cell membrane of Pseudomonas putida
 LadA is a flavoprotein-dependent monooxygenase isolated from a thermophilic microorganism
(Geobacillus thermodenitrificans NG80-2) that activates the long-chain alkanes (C15 to C36) for
degradation
 The Finnerty pathway is a process in which dioxygenase systems are able to transform n-alkanes
first into their corresponding hydroperoxides and then into the corresponding alkan-1-ol.
 For example: Acinetobacter sp. M-l is able grow rapidly on high-molecular-weight alkanes (Cl3
to C44) through oxidation via a n-alkane dioxygenase

10. Mechanism Of Terminal and Subterminal pathway

11. Advantage
High resistant to toxic material
Low sensivity of temperature
Permanent elimination of waste
Disadvantage
Require high amount of O2 concentration
Some chemicals cannot be digested
Site specific requirements

12. REFERENCE
Abbasian, F., Lockington, R., Mallavarapu, M., & Naidu, R. (2015). A Comprehensive
Review of Aliphatic Hydrocarbon Biodegradation by Bacteria. Applied Biochemistry and
Biotechnology, 176(3), 670–699. https://doi.org/10.1007/s12010-015-1603-5
Kulikova, A. E., & Zil’berman, E. N. (1971). Conversions of Chlorine-containing
Aliphatic Compounds in the Presence of Coordination-unsaturated Metals. Russian
Chemical Reviews, 40(3), 256. https://doi.org/10.1070/RC1971v040n03ABEH001917
Mascotti, M. L., Lapadula, W. J., & Juri Ayub, M. (2015). The Origin and Evolution of
Baeyer—Villiger Monooxygenases (BVMOs): An Ancestral Family of Flavin
Monooxygenases. PLoS ONE, 10(7), e0132689.
https://doi.org/10.1371/journal.pone.0132689

13. Mehboob, F., Weelink, S., Saia, F. T., Junca, H., Stams, A. J. M., & Schraa, G.
(2010). Microbial Degradation of Aliphatic and Aromatic Hydrocarbons with
(Per)Chlorate as Electron Acceptor. In K. N. Timmis (Ed.), Handbook of Hydrocarbon
and Lipid Microbiology (pp. 935–945). Springer. https://doi.org/10.1007/978-3-540-
77587-4_66
Nzila, A. (2018). Current Status of the Degradation of Aliphatic and Aromatic
Petroleum Hydrocarbons by Thermophilic Microbes and Future Perspectives.
International Journal of Environmental Research and Public Health, 15(12), 2782.
https://doi.org/10.3390/ijerph15122782
Proposed terminal and subterminal alkane degradation pathways. | Download
Scientific Diagram. (n.d.). Retrieved September 26, 2022, from
https://www.researchgate.net/figure/Proposed-terminal-and-subterminal-alkane-
degradation-pathways_fig9_230618033