| Summary: | 碩士 === 弘光科技大學 === 環境工程研究所 === 100 === Di-n-butyl phthalate (DBP), a phthalate ester (PAE), is the most widely used plasticizing agent in industrial plastic production. Due to its hydrophobicity, it is released into the environment during its production and use, and may be released from plastic products. DBP is listed as a controlled toxic chemical and an endocrine disruptor with proven carcinogenicity, teratogenicity, and endocrine effect by many countries. To prevent the ecological and environmental concern in the production and use of this substance, this study aims to find pure bacterial strains with DBP-reducing ability. Sludge or soil was obtained from city/industrial wastewater treatment plants and paddy fields, and was mixed and domesticated with DBP to explore the DBP removal efficiency of domesticated bacteria in synthesized and real wastewater to obtain a pure DBP-reducing bacterial strain. The DBP-reducing efficiency of isolated pure bacterial strains in synthesized and real wastewater was determined. The results showed that the mixed strains proliferated in the synthesized wastewater with DBP not exceeding 1,000 mg/L and the at least 90% DBP was removed. In the real wastewater with DBP as high as 1,000 mg/L, the bacteria were also viable and a 99% DBP removal efficiency was achieved. Using TSA and R2A isolation mediums, nine pure strains were obtained and DBP degradation tests were performed at 200 mg/L and 500 mg/L. Six of nine (T1, T2, T3, R1, R4 and R5) strains were viable in medium with DBP, and R5 was the strain with the best DBP removal efficiency. R5, a Gram-negative strain, was found to be Deinococcus sp. by 16s rRNA identification. It can survive in synthetic and real wastewater with DBP not exceeding 1,000 mg/L and remove the DBP contained in the sludge or soil.
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