Plasmid-mediated degradation of o- and p-phthalate by Pseudomonas fluorescens

A Pseudomonas fluorescens strain SKP3 capable of utilizing both phthalic ac id and terephthalic acid as sole source of carbon and energy was isolated b y enrichment technique. Phthalic acid, terephthalic acid and protocatechuic acid were easily oxidized by both phthalate-grown and glucose-grown cells without a lag period. Phthalic acid is metabolized through the ortho cleava ge pathway and terephthalic acid through the meta cleavage pathway and the enzymes of the two pathways are constitutive in nature. A large plasmid of approximately 140 kb in size was found to be involved in the degradation of phthalates. The catabolic plasmid pSKL was transferable to different hosts .