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

摘要

A newly isolated strain Agromyces sp. MT-0 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 inoculum size (OD_(600) 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 7143 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-0 has greatly enhanced DEHP disappearance rate in soils, providing great potential for efficiently remediating DEHP-contaminated environment.