Complete degradation of the endocrine disruptor di-(2-ethylhexyl) phthalate by a novel Agromyces sp MT-O strain and its application to bioremediation of contaminated soil

A newly isolated strain Agromyces sp. MT-O could utilize various phthalates and efficiently degraded di-(2-ethylhexyl) phthalate (DEHP). Response surface methodology was successfully employed for the optimization of culture conditions including pH (7.2), temperature (29.6), and inoculumsize (OD600 of 0.2), resulting in almost complete degradation of DEHP (200 mg L-1) within 7 days. At different initial concentrations (50-1000 mg L-1), DEHP degradation curves were fitted well with the first-order kinetic model, and the half-life of DEHP degradation ranged from 0.83 to 2.92 days. Meanwhile, the substrate inhibition model was used to describe the special degradation rate with q(max), K-s, and K-i of 0.6298 day(-1), 86.78 mg L-1, and 714.3 mg L-1, respectively. The GC-MS analysis indicated that DEHP was degraded into mono-ethylhexyl phthalate and phthalate acid before its complete mineralization. Bioaugmentation of DEHP-contaminated soils with strain MT-O has greatly enhanced DEHP disappearance rate in soils, providing great potential for efficiently remediating DEHP-contaminated environment. (C) 2016 Published by Elsevier B.V.