Bacterial Degradation of Low Molecular Weight Polycyclic Aromatic Hydrocarbons; naphthalene, 1-methylnapthalene, and 2-methylnapthalene by Mycobacterium

Alyssa Anne Valentyne


Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants that result from the incomplete combustion of organic substances. These contaminants are a threat to both public health and the environment because they are carcinogenic and persistent. Luckily, bioremediation can occur because some microorganisms are able to degrade these chemicals into less detrimental metabolites. This study examined the rates of degradation when Mycobacterium species RJGII-135 was exposed to 3 particular low molecular weight PAHs; naphthalene, 1-methylnapthalene, and 2-methylnapthalene. Within a 72 hour timeframe, no significant loss of naphthalene was observed. However, the bacteria were able to degrade both 1-methylnaphthalene and 2-methylnapthalene. This suggests that the additional methyl group aids in the Mycobacterium’s metabolism of these specific PAHs. Demethylation was eliminated as a potential metabolic pathway because no naphthalene was measured in the methylated trials. Furthermore, when the microorganism was exposed to all three PAHs of interest, there was no differentiation or preference to either of the methylated naphthalenes. These types of studies are of great importance for the field of toxicology because microbial PAH degradation has the ability to positively impact global pollution clean-up initiatives.


Biodegradation; Polycyclic Aromatic Hydrocarbons; Bioremediation; Mycobacterium

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