A novel biodegradation pathway of the endocrine-disruptor di(2-ethyl hexyl) phthalate by Pleurotus ostreatus based on quantum chemical investigation

Di(2-ethyl hexyl) phthalate (DEHP) is a plasticizer that interfere with endocrine systems in mammals. Growth parameters for Pleurotus ostreatus grown on media containing glucose and different concentrations of DEHP (0, 500 and 1000 mg/L) were evaluated. The highest biomass production was observed in medium supplemented with 1000 mg of DEHP/L. Half-life of DEHP biodegradation, biodegradation constant of DEHP, and percentage of removal efficiency (%E) were also determined. P. ostreatus degraded 100% of DEHP after 504 h. %E was 99.3% and 98.4% for 500 and 1000 mg of DEHP/L, respectively. Intermediate compounds of biodegraded DEHP were identified by GC-MS and a DEHP biodegradation pathway was proposed using quantum chemical investigation. DEHP might be metabolized through three pathways; a de-esterification pathway, an oxidation pathway and an oxidation-hydrolysis pathway, forming phthalic acid, acetic acid and butanediol, respectively. P. ostreatus degrades and uses (as carbon and energy source) high concentrations of DEHP.