Environmental Biotechnology

Applied Microbiology and Biotechnology

, Volume 75, Issue 3, pp 655-663

Polycyclic aromatic hydrocarbon-degrading Mycobacterium isolates: their association with plant roots

  • R. ChildAffiliated withDepartment of Biology, Utah State University
  • , C. D. MillerAffiliated withDepartment of Biology, Utah State University
  • , Y. LiangAffiliated withDepartment of Biological Engineering and Irrigation, Utah State University
  • , G. NarasimhamAffiliated withDepartment of Biological Engineering and Irrigation, Utah State University
  • , J. ChattertonAffiliated withUSDA Forage and Range Research Laboratory, Utah State University
  • , P. HarrisonAffiliated withUSDA Forage and Range Research Laboratory, Utah State University
  • , R. C. SimsAffiliated withDepartment of Biological Engineering and Irrigation, Utah State University
  • , D. BrittAffiliated withDepartment of Biological Engineering and Irrigation, Utah State University
  • , A. J. AndersonAffiliated withDepartment of Biology, Utah State University Email author 

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Abstract

Five environmental mycobacterium isolates that degrade polycyclic aromatic hydrocarbons (PAHs) were associated with barley root surfaces after growth of the seedlings from inoculated seed. Mycobacterium cells were detected along the total root length for four of these isolates. These PAH-degrading mycobacterium strains had hydrophilic cell surfaces, whereas one strain, MCS, that was hydrophobic had reduced association along the root length with no cells being detected from the root tips. The root-tip-competent strain, KMS, was competitive for its root association in the presence of the root-colonizing pseudomonad, Pseudomonas putida KT2440. All mycobacterium strains utilized simple sugars (fructose, glucose) and the trisaccharide 6-kestose, present in barley root washes, for planktonic growth, but they differed in their potential for biofilm formation under in vitro conditions. Mineralization of pyrene by the KMS strain occurred when the components in the barley root wash were amended with labeled pyrene suggesting to us that mineralization could occur in plant rhizospheres containing such mycobacterium strains.

Keywords

Polycyclic aromatic hydrocarbons Root colonization Mycobacterium Remediation