Biodegradation of di(2-ethylhexyl) phthalate by a new bacterial consortium

Abstract

Di(2-ethylhexyl) phthalate (DEHP) with continuous high concentration was used as the sole carbon and energy source to isolate a new bacterial consortium (K1) from agricultural soil covered with plastic film for a long time. Unclassified Comamonadaceae, Achromobacter, and Pseudomonas in K1 were identified as major genera of the consortium by high-throughput sequencing, and unclassified Commanadaceae was first reported to be related to DEHP degradation. Response surface method (RSM) showed that the optimum conditions for K1 to degrade DEHP were 31.4 °C, pH 7.3, and a concentration of 420 mg L−1. K1 maintains normal cell viability and stable DEHP degradation efficiency in the range of 10–3000 mg L−1 DEHP concentration, which is superior to existing research. The biodegradation of DEHP followed first-order kinetics when the initial concentration of DEHP was between 100 and 3,000 mg L−1. GC-MS analysis of different treatment groups showed that DEHP was degraded by the consortium group through the de-esterification pathway, and treatment effect was significantly better than that of the single bacteria treatment group. The subsequent substrate utilization experiment further confirmed that K1 could quickly mineralize DEHP. In addition, K1 has high degradation capacity for the most common phthalate acid esters in the environment. HIGHLIGHTS A bacterial consortium K1 with strong tolerance to DEHP was isolated by high-pressure screening method from agricultural soil long-term covered with plastic mulch.; K1 has a wider concentration adaptation range for DEHP, and can quickly mineralize DEHP and its metabolic intermediates.; First report of unclassified Comamonadaceae associated with DEHP degradation by high-throughput sequencing technology.;

Keywords

• biodegradation
• di(2-ethylhexyl) phthalate
• kinetics
• phthalate-contaminated site remediation
• response surface methodology
• unclassified comamonadaceae