title: Responses of Aromatic-Degrading Microbial Communities to Elevated Nitrate in Sediments.
abstract: A high number of aromatic compounds that have been released into aquatic ecosystems have accumulated in sediment because of their low solubility and high hydrophobicity, causing significant hazards to the environment and human health. Since nitrate is an essential nitrogen component and a more thermodynamically favorable electron acceptor for anaerobic respiration, nitrate-based bioremediation has been applied to aromatic-contaminated sediments. However, few studies have focused on the response of aromatic-degrading microbial communities to nitrate addition in anaerobic sediments. Here we hypothesized that high nitrate inputs would stimulate aromatic-degrading microbial communities and their associated degrading processes, thus increasing the bioremediation efficiency in aromatic compound-contaminated sediments. We analyzed the changes of key aromatic-degrading genes in the sediment samples from a field-scale site for in situ bioremediation of an aromatic-contaminated creek in the Pearl River Delta before and after nitrate injection using a functional gene array. Our results showed that the genes involved in the degradation of several kinds of aromatic compounds were significantly enriched after nitrate injection, especially those encoding enzymes for central catabolic pathways of aromatic compound degradation, and most of the enriched genes were derived from nitrate-reducing microorganisms, possibly accelerating bioremediation of aromatic-contaminated sediments. The sediment nitrate concentration was found to be the predominant factor shaping the aromatic-degrading microbial communities. This study provides new insights into our understanding of the influences of nitrate addition on aromatic-degrading microbial communities in sediments.
authors.affiliation: Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology , Guangzhou 510070, China.|State Key Laboratory of Applied Microbiology Southern China, Guangzhou 510070, China.
authors.forename: Meiying
authors.initials: M
authors.lastname: Xu
authors.affiliation: Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma , Norman, Oklahoma 73019, United States.
authors.forename: Zhili
authors.initials: Z
authors.lastname: He
authors.affiliation: Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology , Guangzhou 510070, China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology , Guangzhou 510070, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Liu
authors.affiliation: Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology , Guangzhou 510070, China.|State Key Laboratory of Applied Microbiology Southern China, Guangzhou 510070, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Guo
authors.affiliation: Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology , Guangzhou 510070, China.|State Key Laboratory of Applied Microbiology Southern China, Guangzhou 510070, China.
authors.forename: Guoping
authors.initials: G
authors.lastname: Sun
authors.affiliation: Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma , Norman, Oklahoma 73019, United States.|Earth Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.|State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University , Beijing 100084, China.
authors.forename: Jizhong
authors.initials: J
authors.lastname: Zhou
mesh_terms: D001673:Biodegradation, Environmental; D002681:China; D017753:Ecosystem; D005798:Genes, Bacterial; D019015:Geologic Sediments / Q000382:microbiology*; D059013:Microbial Consortia / Q000235:genetics / Q000502:physiology*; D009566:Nitrates / Q000378:metabolism*
chemical_list: D009566:Nitrates