Enzymatic Degradation and Detoxification of Diethyl Phthalate by Fusarium oxysporum f. sp.pisi Cutinase

摘要

Phthalate esters are used in the production of polyvinyl chloride to make it flexible and workable and, to a lesser degree, in paints, lacquers, and cosmetics. Phthalates have been found in sediment, water, and air and have also been detected in foods, as they can migrate out of food-packaging materials. Diethyl phthalate (DEP) is a phthalic ester that is present mainly in packaging materials (papers, paperboards, etc.) for aqueous, fatty, and dry foods. DEP is known to cause decrease in the number of live offspring born to female animals that were exposed to DEP. DEP can be mildly irritating when applied to the skin of animals. It can also be slightly irritating when put directly into the eyes of animals. Cutinase is a hydrolytic enzyme that degrades cutin, the cuticular polymer of higher plants. Unlike the other lipolytic enzymes, such as lipases and esterases, cutinase does not require interfacial activation for substrate binding and activity. Cutinases have been largely exploited for esterification and transesterification in chemical synthesis and have also been applied in laundry or dishwashing detergent. In the present study, we investigated the efficacy of two lypolytic enzymes, fungal cutinase and yeast esterase, in the enzymatic degradation of DEP. During enzymatic DEP degradation for an extended period (3 days), degradation products that are not currently classified as endocrine-disrupting chemicals (EDCs) in animals, in humans or in vitro were detected, and their time-course compositional changes were also monitored. To evaluate the other types of potential toxicity of the DEP-derived products, the cellular toxicity of degradation products was measured in detail, using various recombinant bioluminescent bacteria.