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Silver nanoparticle inhibition of polycyclic aromatic hydrocarbons degradation by M ycobacterium species RJGII ‐135
Author(s) -
MuellerSpitz S.R.,
Crawford K.D.
Publication year - 2014
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/lam.12205
Subject(s) - environmental chemistry , chemistry , phenanthrene , silver nanoparticle , naphthalene , bacteria , mycobacterium , carbon fibers , degradation (telecommunications) , microbial biodegradation , microorganism , microbiology and biotechnology , nanoparticle , organic chemistry , biology , nanotechnology , materials science , composite material , genetics , telecommunications , composite number , computer science
Polycyclic aromatic hydrocarbons ( PAH ) are a common environmental contaminant originating from both anthropogenic and natural sources. Mycobacterium species are highly adapted to utilizing a variety of PAH . Silver nanoparticles (Ag NP ) are an emerging contaminant that possess bactericidal properties, interferes with the bacterial membrane and alters function. Mycobacterium sp. strain RJGII ‐135 provided a model bacterium to assess changes in carbon metabolism by focusing on PAH degradation, which is dependent upon passive uptake of hydrophobic molecules into the cell membrane. A mixture of 18 PAH served as a complex mixture of carbon sources for assessing carbon metabolism. At environmentally relevant PAH concentrations, RJGII ‐135 degraded two‐, three‐, and four‐ring PAH within 72 h, but preferentially attacked phenanthrene and fluorene. Total cell growth and PAH degradation were successively reduced when exposed to 0·05–0·5 mg 1 −1 Ag NP . However, 0·05 mg l −1 Ag NP inhibited degradation of naphthalene, acenaphthylene and acenaphthalene. RJGII ‐135 retained the ability to degrade the methylated naphthalenes regardless of Ag NP concentration suggesting that proteins involved in dihydrodiol formation were inhibited. The reduced PAH metabolism of RJGII ‐135 when exposed to sublethal concentrations of Ag NP provides evidence that nanoparticle pollution could alter carbon cycling in soils, sediment and aquatic environments. Significance and Impact of the Study Silver nanoparticle (Ag NP ) pollution threatens bacterial‐mediated processes due to their antibacterial properties. With the widespread commercial use of Ag NP , continued environmental release is inevitable and we are just beginning to understand the potential environmental ramifications of nanoparticle pollution. This study examined Ag NP inhibition of carbon metabolism through the polycyclic aromatic hydrocarbon degradation by Mycobacterium species RJGII ‐135. Sublethal doses altered PAH metabolism, which is dependent upon cell membrane properties and intracellular proteins. The changed carbon metabolism when exposed to sublethal doses of Ag NP suggests broad impacts of this pollution on bacterial carbon cycling in diverse environments.