Screening And Identification Of A Diethyl Phthalate-Degrading Bacterium And Its Biodegradation Characteristics

Phthalate esters (PAEs), an important chemical raw materials, have been wildly used in all kinds of chemical products. And Dibutyl phthalate (DBP) with reproductive toxicity which has a great potential threat to human’s body health. Plus, is one of the most widely used kinds. Recently the mass production and consumption of industrial products lead to the increasing content of DBP in the environment. Therefore, people pay much attention to how to effectively reduce the pollution. And biological methods to degrade such materials will also become the major one to deal with this kind of pollution.A DBP degradation bacterial strain was isolated when using DBP as the only carbon source in the basal medium. After the morphological identification, physiological and biochemical identification and the homology analysis of16S rDNA, this bacterium was identified belonging to the genus Arthrobacter and named as Arthrobacter sp. ZJUTW. Arthrobacter sp. ZJUTW can degrade90%of the800mg/L DBP in14h. The optimal degrading temperature was30℃and the optimal degradation pH was7. Arthrobacter sp. ZJUTW can also well degrade DEP and DMP simultaneously. Arthrobacter sp. ZJUTW can grow well in the medium using the dimethyl phthalic acid, phthalic acid ethyl ester, two phthalic acid methyl, phthalic acid-(2-ethyl has base) ester and catechol as the only carbon source. However, it did not grow in the medium using naphthalene, thiophene, carbazole and phenol as the only carbon source.The crude enzyme of Arthrobacter sp. ZJUTW was extracted by ultra-sonication. DBP degrading enzymes belong to the endoenzyme. The optimal temperature for the crude enzyme is30℃-35℃; and kept stable at10℃-35℃. The effect of the metal ions on the enzyme activity was evaluated. Fe+3had a strong inhibition effect on the enzyme activity while Mg+2improve the enzyme activity. The Michaelis constant (Km) of the crude enzyme to DBP was0.487mmol/L...