Characterization of the Phenol Hydroxylase from Burkholderia kururiensis KP23 Involved in Trichloroethylene Degradation by Gene Cloning and Disruption.

Abstract

Burkholderia kururiensis KP23 was isolated as a trichloroethylene (TCE)-degrading bacterium. Its degrading activity was induced by phenol, suggesting that the degradation is catalyzed by a phenol hydroxylase (PH). To elucidate the involvement of the PH in the degradation of TCE, the gene cluster for the enzyme was cloned and sequenced. The structural genes (phkABCDEFG) and cognate regulatory gene (phkR) were identified in a divergent transcriptional organization. The products are homologous to those of dmpRKLMNOPQ of Pseudomonas putida CF600, sharing 30-62% identity of amino acid sequence, indicating that the PH is a multi-component enzyme. Disruption of phkD encoding a large oxygenase subunit of the enzyme completely abolished the utilization of phenol as well as degradation of TCE by strain KP23. In addition, a disruptant of phkR was not able to grow on phenol and showed no activity to degrade TCE, indicating that PhkR is an activator and controls the expression of phkABCDEFG.

Microbial degradation of phenol and phenolic derivatives

“…The Burkholderia kururiensis KP23 strain was isolated as a trichloroethylene‐degrading bacterium. The degradation activity of this strain is induced by phenol, which proves that the biodegradation is catalyzed by the phenol hydroxylase enzyme . A Burkholderia vietnamiensis strain is capable of actively degrading trichloroethylene and a number of toxic aromatic compounds.…”

Metabolic analysis of the soil microbe Dechloromonas aromatica str. RCB: indications of a surprisingly complex life-style and cryptic anaerobic pathways for aromatic degradation

“…D. aromatica has a fourteen gene insert that encodes members of the mhp -like family of aromatic oxygenases between the tandem tbc 1 and 2-like oxygenase clusters (see Table 2 ), with an inversion of the second region compared to R. eutropha and Burkholderia . Clade analysis indicates a broad substrate phenol degradation pathway in this cluster, with high sequence identity to the TOM gene cluster of Bradyrhizobium , which has the ability to oxidize dichloroethylene, vinyl chlorides, and TCE [ 37 , 38 ]. The VIMSS581522 response regulator gene that occurs between the two identified monooxygenase gene clusters shares 50.3% identity to the Thaurea aromatica tutB gene and 48.2% to the Pseudomonas sp.…”

Aldibereko teknika biologikoen bitartezko lurzoru kutsatuen erremediazioa

“…Gainera, LB400 anduiak moldakortasun kataboliko handia erakutsi izan du konposatu aromatikoen degradaziorako [88,92], eta uzten hazkuntza ere bultzatu dezake [87]. Izan ere, landareen hazkuntza bultzatzen duen nitrogenoa finkatzeaz gain, 1-amino-ziklopropano-1-karboxilato (ACC) deaminasa entzima bakterianoak ACCa (etilenoaren aintzindaria) hidrolizatu eta etileno-mailak jaisten ditu; ondorioz, sustraiak haztea bultzatzen du [87][88][89][90][91][92][93].…”