title: Isolation and characterization of a phenol-degrading Rhodococcus sp. strain AQ5NOL 2 KCTC 11961BP.
abstract: In this work, we report on the isolation of a phenol-degrading Rhodococcus sp. with a high tolerance towards phenol. The isolate was identified as Rhodococcus sp. strain AQ5NOL 2, based on 16S rDNA analysis. The strain degraded phenol using the meta pathway, a trait shared by many phenol-degraders. In addition to phenol biodegradation, the strain was also capable of degrading diesel. Strain AQ5NOL 2 exhibited a broad optimum temperature for growth on phenol at between 20 °C and 35 °C. The best nitrogen sources were ammonium sulphate, glycine or phenylalanine, followed by proline, nitrate, leucine, and alanine (in decreasing efficiency). Strain AQ5NOL 2 showed a high tolerance and degradation capacity of phenol, for it was able to register growth in the presence of 2000 mg l(-1) phenol. The growth of this strain on phenol as sole carbon and energy source were modeled using Haldane kinetics with a maximal specific growth rate (μ(max)) of 0.1102 hr(-1), a half-saturation constant (K(s) ) of 99.03 mg l(-1) or 1.05 mmol l(-1), and a substrate inhibition constant (K(i)) of 354 mg l(-1) or 3.76 mmol l(-1). Aside from phenol, the strain could utilize diesel, 2,4-dinitrophenol and ρ-cresol as carbon sources for growth. Strain AQ5NOL 2 exhibited inhibition of phenol degradation by Zn(2+), Cu(2+), Cr(6+), Ag(+) and Hg(2+) at 1 mg l(-1).
authors.affiliation: Department of Biochemistry, University Putra Malaysia, UPM 43400 Serdang, Selangor, Malaysia.
authors.forename: N M
authors.initials: NM
authors.lastname: Arif
authors.forename: S A
authors.initials: SA
authors.lastname: Ahmad
authors.forename: M A
authors.initials: MA
authors.lastname: Syed
authors.forename: M Y
authors.initials: MY
authors.lastname: Shukor
mesh_terms: D000704:Analysis of Variance; D001673:Biodegradation, Environmental; D002244:Carbon / Q000378:metabolism; D004269:DNA, Bacterial / Q000032:analysis / Q000737:chemistry / Q000235:genetics; D005742:Gasoline; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D019216:Metals, Heavy / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D010636:Phenols / Q000378:metabolism*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012240:Rhodococcus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D013696:Temperature
chemical_list: D004269:DNA, Bacterial; D005742:Gasoline; D019216:Metals, Heavy; D010636:Phenols; D012336:RNA, Ribosomal, 16S; D002244:Carbon; D009584:Nitrogen