Isolation and characterization of a highly efficient DEHP-degrading bacterium

Abstract:

[Objective] We isolated and identified di(2-ethylhexy) phthalate-degrading strains. [Methods] We isolated and domesticated the strain by gradient enrichment culture. We identified the strain by 16S rRNA gene and gyrB gene sequence analysis, combined with morphological, physiological and biochemical characterization. And we analyzed the degradation characteristics of the strain using High Performance Liquid Chromatography (HPLC). [Results] A strain (named HS-NH1) with DEHP-degrading activity was obtained and identified as Gordonia sp.. The optimum temperature and pH for growth and degradation of Gordonia sp. HS-NH1 were 30 °C and 7.0 respectively, strain HS-NH1 was able to almost degrade 500 mg/L di(2-ethylhexy) phthalate to above 90% within 60 hours. One of the major metabolites of di(2-ethylhexy) phthalate degradation were identified as phthalic acid by HPLC. A substrate utilization test showed that HS-NH1was also able to utilize many other common phthalates. [Conclusion] A bacterial strain with a high di(2-ethylhexy) phtha-late-degrading efficiency was obtained, and the strain may have a potential application in dealing with the pollution caused by phthalate esters.

Key words:Di(2-ethylhexy) phthalate (DEHP), Microbial degradation, gyrB gene, Gordonia sp., Phthalic acid