title: Enzymatic degradation of aromatic hydrocarbon intermediates using a recombinant dioxygenase immobilized onto surfactant-activated carbon nanotube.
abstract: This study examined the enzymatic decomposition of aromatic hydrocarbon intermediates (catechol, 4-chlorocatechol, and 3-methylcatechol) using a dioxygenase immobilized onto single-walled carbon nanotube (SWCNT). The surfaces of SWCNTs were activated with surfactants. The dioxygenase was obtained by recombinant technique: the corresponding gene was cloned from Arthrobacter chlorophenolicus A6, and the enzyme was overexpressed and purified subsequently. The enzyme immobilization yield was 62%, and the high level of enzyme activity was preserved (60-79%) after enzyme immobilization. Kinetic analyses showed that the substrate utilization rates and the catalytic efficiencies of the immobilized enzyme for all substrates (target aromatic hydrocarbon intermediates) tested were similar to those of the free enzyme, indicating that the loss of enzyme activity was minimal during enzyme immobilization. The immobilized enzyme was more stable than the free enzyme against abrupt changes in pH, temperature, and ionic strength. Moreover, it retained high enzyme activity even after repetitive use.
authors.affiliation: Department of Environmental Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701, Republic of Korea.
authors.forename: Yanasinee
authors.initials: Y
authors.lastname: Suma
authors.affiliation: Department of Environmental Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701, Republic of Korea.
authors.forename: Heejun
authors.initials: H
authors.lastname: Lim
authors.affiliation: Department of Environmental Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701, Republic of Korea.
authors.forename: Oh Sung
authors.initials: OS
authors.lastname: Kwean
authors.affiliation: Department of Environmental Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701, Republic of Korea.
authors.forename: Suyeon
authors.initials: S
authors.lastname: Cho
authors.affiliation: Department of Environmental Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701, Republic of Korea.
authors.forename: Junwon
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Environmental Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701, Republic of Korea.
authors.forename: Yohan
authors.initials: Y
authors.lastname: Kim
authors.affiliation: Department of Environmental Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701, Republic of Korea.
authors.forename: Christina S
authors.initials: CS
authors.lastname: Kang
authors.affiliation: Department of Environmental Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701, Republic of Korea. Electronic address: hankim@konkuk.ac.kr.
authors.forename: Han S
authors.initials: HS
authors.lastname: Kim
mesh_terms: D001173:Arthrobacter / Q000201:enzymology; D002606:Charcoal / Q000494:pharmacology*; D049308:Dioxygenases / Q000378:metabolism*; D004795:Enzyme Stability / Q000187:drug effects; D004800:Enzymes, Immobilized / Q000378:metabolism*; D006841:Hydrocarbons, Aromatic / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009994:Osmolar Concentration; D011994:Recombinant Proteins / Q000378:metabolism*; D012996:Solutions; D013501:Surface-Active Agents / Q000494:pharmacology*; D013696:Temperature
chemical_list: D004800:Enzymes, Immobilized; D006841:Hydrocarbons, Aromatic; D037742:Nanotubes, Carbon; D011994:Recombinant Proteins; D012996:Solutions; D013501:Surface-Active Agents; D002606:Charcoal; D049308:Dioxygenases
keywords: Dioxygenase; Enzyme immobilization; Single-walled carbon nanotube; Stability; Surfactant