Degradation and Biosorption of Envirinmental Endocrine Discruptor Di-(2-ethylhexyl) phthalate (DEHP) by Gordonia sp. YK1

In this study, the isolation of DEHP-degrading microorganism was successfully achieved by establishing highly enriched aerobic cultures capable of degrading DEHP. DEHP in the culture with the isolated microorganism was rapidly degraded with the growth of cells and disappeared in 48 hr (more than 90% degradation). Based on 16S rDNA analysis, the isolated DEHP-degrading microorganism belongs to the Gordonia. Because the DEHP-degrading microorganism, Gordonia sp. YK1, was attached to DEHP droplets and formed aggregation in the liquid medium during the degradation of DEHP, biosorption of DEHP by Gordonia sp. YK1 was investigated with 50 ppm DEHP by detecting DEHP concentration in supernatant and biomass phases. With 11 mg biomass and 50 ppm DEHP, more than 60% of DEHP was removed by biosorption in 15 min, and adsorbed DEHP was degraded rapidly (73% degradation of DEHP in 30 min). Interestingly, cell attachment to DEHP oil drops was observed even with the autoclaved biomass of Gordonia sp. YK1. Since it is known that there are long aliphatic chains of the mycolic acids in cell wall for the Gordonia genera, strong hydrophobicity of the cell surface of Gordonia sp. YK1 due to mycolic acids is likely to be involved in DEHP biosorption and, consequently, effective DEHP biodegradation by facilitating DEHP uptake.