Functional analysis of alkane hydroxylase system derived from Pseudomonas aeruginosa E7 for low molecular weight polyethylene biodegradation

• Pseudomonas aeruginosa E7 exhibiting high activity toward polyethylene degradation was isolated from a beach soil.
• alkB participated directly whereas rubredoxin and rubredoxin reductase played indirect role in the polyethylene degrdation.
• The rubredoxin and rubredoxin reductase exerted a positive role in the polyethylene degradation by alkane monooxygenase.

A bacterium capable of low-molecular-weight polyethylene degradation was isolated from beach soil that had previously been contaminated by an oil spill. The bacterium was identified as Pseudomonas aeruginosa E7. Genes encoding proteins constituting the alkane hydroxylase (AH) system, such as alkane monooxygenase, rubredoxin, and rubredoxin reductase were detected. The genes were cloned and the expressions of the inserted genes were confirmed using reverse transcription-PCR and SDS-PAGE. Comparison of the polyethylene biodegradation activities of the isolated strain and recombinant strains prepared by cloning of each gene revealed that the isolated strain displayed the highest activity, followed by BCARB (encoding alkB, rubA1, rubA2 and rubB), BCAR (encoding alkB, rubA1 and rubA2) and BCA (encoding alkB).

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