Aerobic biodegradation of di-n-butyl phthalate by Xiangjiang River sediment and microflora analysis

Di-n-butyl phthalate (DBP), one of phthalate acid esters (PAEs), was investigated to determine its biodegradation rate using Xiangjiang River sediment and find potential DBP degraders in the enrichment culture of the sediment. The sediment sample was incubated with an initial concentration of DBP of 100 mg/L for 5 d. The biodegradation rate of DBP was detected using HPLC and the degraded products were analyzed by GC/MS. Subsequently, the microbial diversity of the enrichment culture was analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The results reveal that almost 100% of DBP is degraded after merely 3 d, generating two main degraded products: mono-butyl phthalate (MBP) and 9-octadecenoic acid. After a six-month enrichment period under the pressure of DBP, the dominant family in the final enrichment culture is clustered with the Comamonas sp., the remaining are affiliated with Sphingomonas sp., Hydrogenophaga sp., Rhizobium sp., and Acidovorax sp. The results show the potential of these bacteria to be used in the bioremediation of DBP in the environment.