Delftia tsuruhatensis sp. nov., a terephthalateassimilating bacterium isolated from activated sludge Terephthalate is an aromatic compound used in the production of polyethylene terephthalate (PET) and is one of the top 50 most abundantly manufactured chemicals in the world (Savostianoff, 1990). A large amount of terephthalate is discharged during production of PET bottles and purification of terephthalic acid. Biological degradation of this compound has therefore been of interest in recent years.Several micro-organisms have been shown to degrade terephthalate under aerobic conditions, including the Gram-positive bacteria Nocardia sp. strain DSM 43251 (Engelhardt et al., 1979), a Bacillus species (Karegoudar & Pujar, 1985) and Dietzia sp. strain GS-1 (Sugimori et al., 2000). Among the Proteobacteria, Bordetella sp. strain K1, Pseudomonas sp. strain C4S (Kimura & Ito, 2001) and two Comamonas testosteroni strains, T-2 (Schläfli et al., 1994) and YZW-D (Wang et al., 1995), have demonstrated the ability to degrade terephthalate.Most of these micro-organisms have been reported to produce protocatechuate as an intermediate metabolite.The enzymic system responsible for the degradation of terephthalate has been thoroughly studied for C. testosteroni strain T-2. In that strain, terephthalate is degraded to protocatechuate by the terephthalate 1,2-dioxygenase system (TERDOS) (Schläfli et al., 1994) and protocatechuate is then metabolized via the meta cleavage pathway. Another C. testosteroni strain, YZW-D, reportedly uses a similar enzyme system for degradation of terephthalate (Wang et al., 1995).Recently, a novel terephthalate-assimilating bacterium, designated strain T7 T , was isolated from the activated sludge of a domestic wastewater treatment plant. The isolate could utilize terephthalate as sole carbon and energy source. Based on 16S rRNA gene sequences and phylogenetic analyses, strain T7T was placed in the genus Delftia;Abbreviations: MLSS, mixed liquor suspended solids; PET, polyethylene terephthalate; TERDOS, terephthalate 1,2-dioxygenase system; TOC, total organic carbon.