Xenobiotic biodegradation test using attached bacteria in synthetic seawater

Area of Science:

• Environmental microbiology
• Biotechnology
• Marine science

Background:

• Aniline is a reference chemical for biodegradability studies.
• Marine environments require specific biodegradation assessments.
• Attached biomass in biofilm reactors offers a controlled system.

Purpose of the Study:

• To evaluate the aerobic biodegradability of aniline in synthetic seawater using a biofilm chemostat reactor (BCR).
• To compare the performance of BCRs with traditional shake flask tests.
• To identify key parameters influencing the biodegradation process in a marine context.

Main Methods:

• Utilized marine bacteria inocula from fish aquarium filters, pretreated by filtration and centrifugation.
• Employed a continuously fed biofilm chemostat reactor (BCR) for biodegradation experiments.
• Varied parameters including initial xenobiotic to inoculum density ratio (S0/X0), dissolved oxygen, and hydraulic residence time.

Main Results:

• BCRs demonstrated effective screening of biodegradability in synthetic seawater.
• S0/X0 ratio, dissolved oxygen, and hydraulic residence time were identified as critical factors controlling biodegradation length.
• Addition of a cosubstrate did not enhance biodegradation efficiency.

Conclusions:

• Marine biofilm chemostat reactors with high attached bacterial density (approx. 10(7) cells cm-2) are suitable for biodegradability screening.
• Optimized BCR operation using synthetic seawater and nitrogen is effective for assessing chemical fate in marine ecosystems.
• This method provides a reliable tool for environmental risk assessment of chemicals in marine environments.