title: Environmental proteomics reveals early microbial community responses to biostimulation at a uranium- and nitrate-contaminated site.
abstract: High-performance MS instrumentation coupled with improved protein extraction techniques enables metaproteomics to identify active members of soil and groundwater microbial communities. Metaproteomics workflows were applied to study the initial responses (i.e. 4 days post treatment) of the indigenous aquifer microbiota to biostimulation with emulsified vegetable oil (EVO) at a uranium-contaminated site. Members of the Betaproteobacteria (i.e. Dechloromonas, Ralstonia, Rhodoferax, Polaromonas, Delftia, Chromobacterium) and the Firmicutes dominated the biostimulated aquifer community. Proteome characterization revealed distinct differences between the microbial biomass collected from groundwater influenced by biostimulation and groundwater collected upgradient of the EVO injection points. In particular, proteins involved in ammonium assimilation, EVO degradation, and polyhydroxybutyrate granule formation were prominent following biostimulation. Interestingly, the atypical NosZ of Dechloromonas spp. was highly abundant, suggesting active nitrous oxide (N2 O) respiration. c-Type cytochromes were barely detected, as was citrate synthase, a biomarker for hexavalent uranium reduction activity, suggesting that uranium reduction has not commenced 4 days post EVO amendment. Environmental metaproteomics identified microbial community responses to biostimulation and elucidated active pathways demonstrating the value of this technique as a monitoring tool and for complementing nucleic acid-based approaches.
authors.affiliation: Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
authors.forename: Karuna
authors.initials: K
authors.lastname: Chourey
authors.forename: Silke
authors.initials: S
authors.lastname: Nissen
authors.forename: Tatiana
authors.initials: T
authors.lastname: Vishnivetskaya
authors.forename: Manesh
authors.initials: M
authors.lastname: Shah
authors.forename: Susan
authors.initials: S
authors.lastname: Pfiffner
authors.forename: Robert L
authors.initials: RL
authors.lastname: Hettich
authors.forename: Frank E
authors.initials: FE
authors.lastname: Löffler
mesh_terms: D001419:Bacteria / Q000187:drug effects / Q000378:metabolism; D001673:Biodegradation, Environmental / Q000187:drug effects; D004655:Emulsions; D004783:Environmental Microbiology; D053858:Metabolic Networks and Pathways / Q000187:drug effects; D064307:Microbiota / Q000187:drug effects; D009566:Nitrates / Q000302:isolation & purification*; D010938:Plant Oils / Q000494:pharmacology*; D040901:Proteomics / Q000379:methods*; D012989:Soil Pollutants / Q000302:isolation & purification*; D014501:Uranium / Q000302:isolation & purification*
chemical_list: D004655:Emulsions; D009566:Nitrates; D010938:Plant Oils; D012989:Soil Pollutants; D014501:Uranium
keywords: Bioremediation; Emulsified vegetable oil (EVO); Environmental proteomics; Groundwater; Microbiology; Oak Ridge IFRC