Diversity and Activity of PAH-Degrading Bacteria in the Phyllosphere of Ornamental Plants

Abstract

Phyllosphere bacteria on ornamental plants were characterized based on their diversity and activity towards the removal of polycyclic aromatic hydrocarbons (PAHs), the major air pollutants in urban area. The amounts of PAH-degrading bacteria were about 1-10% of the total heterotrophic phyllosphere populations and consisted of diverse bacterial species such as Acinetobacter, Pseudomonas, Pseudoxanthomonas, Mycobacterium, and uncultured bacteria. Bacterial community structures analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis from each plant species showed distinct band patterns. The uniqueness of these phyllosphere bacterial communities was partly due to the variation in leaf morphology and chemical properties of ornamental plants. The PAH degradation activity of these bacteria was monitored in gas-tight systems containing sterilized or unsterilized leaves. The results indicated that phyllosphere bacteria on unsterilized leaves were able to enhance the activity of leaves for phenanthrene removal. When compared between plant species, phenanthrene removal efficiency corresponded to the size of phenanthrene-degrading bacteria. In addition, phyllosphere bacteria on Wrightia religiosa were able to reduce other PAHs such as acenaphthylene, acenaphthene, and fluorine in 60-ml glass vials and in a 14-l glass chamber. Thus, phyllosphere bacteria on ornamental plants may play an important role in natural attenuation of airborne PAHs in urban areas.

The abundant occurrence of hydrocarbon-utilizing bacteria in the phyllospheres of cultivated and wild plants in Kuwait

“…There are a few recent reports, that plant leaves accommodate in their phyllospheres considerable numbers of hydrocarbonutilizing microorganisms (Al-Mailem et al, 2010;Yutthammo, 2010;Sorkhoh et al, 2011;Ali et al, 2012). Predominant among those were various species belonging to the genera Arthrobacter, Bacillus, Microbacterium and Rhodococcus (Actinobacteria and Firmicutes).…”

Bioremediation of Atmospheric Hydrocarbons via Bacteria Naturally Associated with Leaves of Higher Plants

“…The tough procedure currently in use was similar to that described by earlier investigators (Yadav et al 2004;Yutthammo et al 2010). It consisted of immersing 5 g fresh leaves in 100 ml 0.1 M potassium phosphate buffer, pH 7.0, shaking for 30 min and finally sonicating in an ultrasonic bath for 10 min.…”

“…There are relatively few reports in the literature indicating that plant leaves harbor hydrocarbonoclastic bacteria (Waight et al 2007;Yutthammo et al 2010;Al-Awadhi et al 2012a; Ali et al 2012). Reportedly, most of these organisms are more effective in the removal of aromatic than aliphatic hydrocarbons.…”

Isolation and Genetic Characterization of Aurantimonas and Methylobacterium Strains from Stems of Hypernodulated Soybeans

“…(Table S3). Members of these genera have been isolated from the phyllosphere and are reported to be degraders of air pollutants (44,60) and to be methylotrophic (4,27), suggesting that they might also play a role as scavengers of monocarbon wastes from plants similar to the role played by Methylobacterium species in the phyllosphere (6).…”