Complete degradation of di-n-octyl phthalate by biochemical cooperation between Gordonia sp. strain JDC-2 and Arthrobacter sp. strain JDC-32 isolated from activated sludge

Two bacterial strains were isolated from activated sludge using mixtures of phthalic acid esters (PAEs) as the sole source of carbon and energy. One of the isolates was identified as Gordonia sp. strain JDC-2 and the other as Arthrobacter sp. strain JDC-32, mainly through 16S rRNA gene sequence analysis. Gordonia sp. strain JDC-2 rapidly degraded di-n-octyl phthalate (DOP) into phthalic acid (PA), which accumulated in the culture medium. Arthrobacter sp. strain JDC-32 degraded PA but not DOP. The co-culture of Gordonia sp. strain JDC-2 and Arthrobacter sp. strain JDC-32 degraded DOP completely by overcoming the degradative limitations of each species alone. The biochemical pathway of DOP degradation by Gordonia sp. strain JDC-2 was proposed based on the identified degradation intermediates. The results suggest that DOP is completely degraded by the biochemical cooperation of different microorganisms isolated from activated sludge.