Actions of a versatile fluorene-degrading bacterial isolate on polycyclic aromatic compounds

Area of Science:

• Environmental Microbiology
• Bioremediation
• Bacterial Metabolism

Background:

• Polycyclic aromatic compounds (PACs) are persistent environmental pollutants.
• Microbial degradation is a key strategy for PAC remediation.
• Pseudomonas cepacia strains are known for their metabolic versatility.

Purpose of the Study:

• To investigate the metabolic capabilities of Pseudomonas cepacia F297 for degrading fluorene and other PACs.
• To elucidate the biochemical pathways involved in fluorene metabolism.
• To assess the potential of strain F297 for bioremediation of PAC-contaminated environments.

Main Methods:

• Culturing Pseudomonas cepacia F297 with fluorene as the sole carbon source.
• Analyzing growth yields and identifying metabolic intermediates using gas chromatography-mass spectrometry (GC-MS).
• Testing the degradation of various PACs and a creosote-PAC mixture.

Main Results:

• Strain F297 assimilated approximately 40% of fluorene carbon, producing a ring meta-cleavage product and 1-indanone.
• The bacterium utilized a broad range of PACs, including naphthalene, phenanthrene, and anthracene, for growth.
• Metabolic reactions included aromatic ring oxidation/cleavage, methyl group oxidation, methylenic oxidation, and sulfur oxidation.
• Complete removal of 2- to 3-ring aromatic compounds from a creosote-PAC mixture within 14 days was observed.

Conclusions:

• Pseudomonas cepacia F297 possesses versatile enzymatic machinery for the degradation of diverse PACs.
• The metabolic pathways employed are analogous to naphthalene degradation, involving ring cleavage and various oxidation reactions.
• Strain F297 shows significant potential for the bioremediation of environments contaminated with PACs and creosote.