Zhou Z.,University of Illinois at Urbana - Champaign |
Zhou Z.,National University of Singapore |
Raskin L.,University of Illinois at Urbana - Champaign |
Raskin L.,University of Michigan |
And 2 more authors.
Applied and Environmental Microbiology | Year: 2010
Current agricultural practices involve inclusion of antimicrobials in animal feed and result in manure containing antimicrobials and antimicrobial-resistant microorganisms. This work evaluated the effects of land application of swine manure on the levels of tetracycline, macrolide, and lincosamide antimicrobials and on macrolide, lincosamide, and streptogramin B (MLSB) resistance in field soil samples and laboratory soil batch tests. MLSB and tetracycline antimicrobials were quantified after solid-phase extraction using liquid chromatography-tandem mass spectrometry. The prevalence of the ribosomal modification responsible for MLSB resistance in the same samples was quantified using fluorescence in situ hybridization. Macrolide antimicrobials were not detected in soil samples, while tetracyclines were detected, suggesting that the latter compounds persist in soil. No significant differences in ribosomal methylation or presumed MLSB resistance were observed when amended and unamended field soils were compared, although a transient (<20-day) increase was observed in most batch tests. Clostridium cluster XIVa accounted for the largest fraction of resistant bacteria identified in amended soils. Overall, this study did not detect a persistent increase in the prevalence of MLSB resistance due to land application of treated swine manure. Copyright © 2010, American Society for Microbiology. All Rights Reserved.
Andrus J.M.,University of Illinois at Urbana - Champaign |
Andrus J.M.,Waterborne Environmental Inc. |
Porter M.D.,University of Illinois at Urbana - Champaign |
Porter M.D.,Environmental Resources Management Inc. |
And 7 more authors.
Microbial Ecology | Year: 2014
Denitrifying biofilters can remove agricultural nitrates from subsurface drainage, reducing nitrate pollution that contributes to coastal hypoxic zones. The performance and reliability of natural and engineered systems dependent upon microbially mediated processes, such as the denitrifying biofilters, can be affected by the spatial structure of their microbial communities. Furthermore, our understanding of the relationship between microbial community composition and function is influenced by the spatial distribution of samples. In this study we characterized the spatial structure of bacterial communities in a denitrifying biofilter in central Illinois. Bacterial communities were assessed using automated ribosomal intergenic spacer analysis for bacteria and terminal restriction fragment length polymorphism of nosZ for denitrifying bacteria. Non-metric multidimensional scaling and analysis of similarity (ANOSIM) analyses indicated that bacteria showed statistically significant spatial structure by depth and transect, while denitrifying bacteria did not exhibit significant spatial structure. For determination of spatial patterns, we developed a package of automated functions for the R statistical environment that allows directional analysis of microbial community composition data using either ANOSIM or Mantel statistics. Applying this package to the biofilter data, the flow path correlation range for the bacterial community was 6.4 m at the shallower, periodically inundated depth and 10.7 m at the deeper, continually submerged depth. These spatial structures suggest a strong influence of hydrology on the microbial community composition in these denitrifying biofilters. Understanding such spatial structure can also guide optimal sample collection strategies for microbial community analyses. © 2013 Springer Science+Business Media New York.
Hutchison J.M.,3230C Newmark Civil Engineering Laboratory |
Poust S.K.,3230C Newmark Civil Engineering Laboratory |
Poust S.K.,Joint BioEnergy Institute |
Kumar M.,3230C Newmark Civil Engineering Laboratory |
And 5 more authors.
Environmental Science and Technology | Year: 2013
Existing methods for perchlorate remediation are hampered by the common co-occurrence of nitrate, which is structurally similar and a preferred electron acceptor. In this work, the potential for perchlorate removal using cell-free bacterial enzymes as biocatalysts was investigated using crude cell lysates and soluble protein fractions of Azospira oryzae PS, as well as soluble protein fractions encapsulated in lipid and polymer vesicles. The crude lysates showed activities between 41 700 to 54 400 U L-1 (2.49 to 3.06 U mg -1 total protein). Soluble protein fractions had activities of 15 400 to 29 900 U L-1 (1.70 to 1.97 U mg-1) and still retained an average of 58.2% of their original activity after 23 days of storage at 4 C under aerobic conditions. Perchlorate was removed by the soluble protein fraction at higher rates than nitrate. Importantly, perchlorate reduction occurred even in the presence of 500-fold excess nitrate. The soluble protein fraction retained its function after encapsulation in lipid or polymer vesicles, with activities of 13.8 to 70.7 U L-1, in agreement with theoretical calculations accounting for the volume limitation of the vesicles. Further, encapsulation mitigated enzyme inactivation by proteinase K. Enzyme-based technologies could prove effective at perchlorate removal from water cocontaminated with nitrate or sulfate. © 2013 American Chemical Society.