title: Complete degradation of di-n-octyl phthalate by Gordonia sp. strain Dop5.
abstract: The present study describes the assimilation of di-n-octyl phthalate by an aerobic bacterium, isolated from municipal waste-contaminated soil sample utilizing di-n-octyl phthalate as the sole source of carbon and energy. The isolate was identified as Gordonia sp. based on the morphological, nutritional and biochemical characteristics as well as 16S rRNA gene sequence analysis. A combination of chromatographic and spectrometric analyses revealed a complete di-n-octyl assimilation pathway. In the degradation process, mono-n-octyl phthalate, phthalic acid, protocatechuic acid and 1-octanol were identified as the degradation products of di-n-octyl phthalate. Furthermore, phthalic acid was metabolized via protocatechuic acid involving protocatechuate 3,4-dioxygenase while 1-octanol was metabolized by NAD(+)-dependent dehydrogenases to 1-octanoic acid, which was subsequently degraded via β-oxidation, ultimately, leading to tricarboxylic acid cycle intermediates. Apart from phthalic acid and 1-octanol metabolizing pathway enzymes, two esterases, di-n-octyl phthalate hydrolase and mono-n-octyl phthalate hydrolase involved in di-n-octyl phthalate degradation were found to be inducible in nature. This is the first report on the metabolic pathway involved in the complete degradation of di-n-octyl phthalate by a single bacterial isolate, which is also capable of efficiently degrading other phthalate esters of environmental concern having either shorter or longer alkyl chains.
authors.affiliation: Department of Microbiology, Bose Institute, P-1/12, C.I.T. Scheme VII M, Kolkata, India.
authors.forename: Jayita
authors.initials: J
authors.lastname: Sarkar
authors.affiliation: Department of Microbiology, Bose Institute, P-1/12, C.I.T. Scheme VII M, Kolkata, India.
authors.forename: Piyali Pal
authors.initials: PP
authors.lastname: Chowdhury
authors.affiliation: Department of Microbiology, Bose Institute, P-1/12, C.I.T. Scheme VII M, Kolkata, India. Electronic address: tapan@bic.boseinst.ernet.in.
authors.forename: Tapan K
authors.initials: TK
authors.lastname: Dutta
mesh_terms: D020003:1-Octanol / Q000378:metabolism; D001673:Biodegradation, Environmental; D002952:Citric Acid Cycle; D004950:Esterases / Q000302:isolation & purification / Q000378:metabolism; D033601:Gordonia Bacterium / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D063347:Native Polyacrylamide Gel Electrophoresis; D010795:Phthalic Acids / Q000032:analysis / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000737:chemistry / Q000235:genetics; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D010795:Phthalic Acids; D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants; C041260:mono-n-octyl phthalate; C010715:di-n-octyl phthalate; D004950:Esterases; D020003:1-Octanol