title: [Effects of nitrate on organic removal and microbial community structure in the sediments].
abstract: The strategy promoted pollutant degradation and transformation under the anaerobic circumstance by adding nitrate as an electron acceptor has been widely used in sediment bioremediation. However, few literature reports on organic removal characteristics and microbial community responses in the contaminated river sediment under the nitrate reduction condition. Methods including the polar and non-polar chemical fractionation, relative abundance detection of organic matters by GC-MS were combined and applied to investigate organic removals and PCR-DGGE analysis was used for microbial community structures in sediment incubation systems with or without calcium nitrate addition. The results indicated that the addition of calcium nitrate could significantly enhance removal efficiencies of organic pollutants. The removal efficiency of total organic carbon (TOC) and the total peak area of organic matters in GC-MS were 47.25% and 29.55% which were higher than those of the control. The effect descending order of organic pollutants was: silicon materials > alkanes > polycyclic aromatic hydrocarbons > heterocyclic compounds > olefins > benzene homologues > polar compounds > phthalates > aldehydes and ketones > alkyl esters. And removal rates of silicon materials, the persistent organic pollutants, benzene homologues and heterocyclic compounds were 46.73%, 36.25%, 23.19% and 35.92% which were higher than those of the control. The PCR-DGGE profile of bacterial 16S rDNA V3 fragments showed obviously different microbial community structures between the treatment and the control systems. Blastn analysis revealed that sequences of 10 predominant bands from DGGE profile were closely related to Proteobacteria, Actinobacteria, Clostridia, Chloroflexi, Caldiserica and uncultured bacterium. The research findings provide some helpful scientific information for promoting organic pollutant removal of river sediment by nitrate reduction.
authors.affiliation: Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China. liujin1926@126.com
authors.forename: Jin
authors.initials: J
authors.lastname: Liu
authors.forename: Dai-Yong
authors.initials: DY
authors.lastname: Deng
authors.forename: Guo-Ping
authors.initials: GP
authors.lastname: Sun
authors.forename: Yong-Ding
authors.initials: YD
authors.lastname: Liu
authors.forename: Mei-Ying
authors.initials: MY
authors.lastname: Xu
mesh_terms: D001419:Bacteria / Q000145:classification / Q000378:metabolism*; D001673:Biodegradation, Environmental; D017610:Calcium Compounds / Q000737:chemistry; D041862:Chloroflexi / Q000378:metabolism; D019015:Geologic Sediments / Q000737:chemistry / Q000382:microbiology*; D009566:Nitrates / Q000737:chemistry*; D009930:Organic Chemicals / Q000302:isolation & purification*; D010084:Oxidation-Reduction; D020560:Proteobacteria / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D017610:Calcium Compounds; D009566:Nitrates; D009930:Organic Chemicals; D014874:Water Pollutants, Chemical; C059948:calcium nitrate