Phenanthrene biodegradation by halophilic Martelella sp. AD-3

Area of Science:

• Environmental Microbiology
• Bioremediation
• Biochemistry

Background:

• Polycyclic Aromatic Hydrocarbons (PAHs) are persistent environmental pollutants.
• Halophilic bacteria offer unique advantages for bioremediation in saline environments.
• Phenanthrene is a model PAH for studying biodegradation pathways.

Purpose of the Study:

• To evaluate the phenanthrene-degrading capacity of the halophilic bacterium Martelella species AD-3.
• To determine optimal conditions for phenanthrene biodegradation by strain AD-3.
• To elucidate the metabolic pathways involved in phenanthrene degradation.

Main Methods:

• High-Performance Liquid Chromatography (HPLC) and Gas Chromatography-Mass Spectrometry (GC-MS) for metabolite identification.
• Bioassays to assess phenanthrene degradation efficiency under varying salinity, pH, and concentration.
• Toxicity assessments using Vibrio fischeri.

Main Results:

• Strain AD-3 efficiently degraded phenanthrene (200 mg/L) within 6 days at 3% salinity and pH 9.0.
• Degradation occurred across a wide range of salinities (0.1-15%) and pHs (6.0-10.0).
• Two distinct metabolic routes were proposed, leading to reduced toxicity of phenanthrene and its metabolites.

Conclusions:

• Martelella species AD-3 demonstrates high potential for phenanthrene biodegradation.
• The identified dual degradation pathways contribute to effective detoxification.
• This halophilic strain shows promise for remediating PAH-contaminated hypersaline environments.