title: Microbial bioavailability of dissolved organic nitrogen (DON) in the sediments of Lake Shankou, Northeastern China.
abstract: Dissolved organic nitrogen (DON) extracted from Lake Shankou sediments using KCl was isolated into hydrophobic and hydrophilic fractions. The bioavailabilities of the hydrophobic and hydrophilic fractions to three types of bacterial communities collected from sediments, activated sludge and compost products were examined. The DON recoveries obtained by DAX-8 and cation exchange resins treatment were 96.17%±1.58% and 98.14%±0% for the samples obtained from N4 and N14 stations, respectively. After 25 days of incubation at 25°C, most DON (59% to 96%) was degraded. Hydrophilic DON exhibited a higher reduction rate than hydrophobic DON during the growth phase. Untreated wastewater from Changshuihe town was the main degradable DON source to station N4, and 93% of hydrophilic DON and 80% of hydrophobic DON were degraded. Station N14 received a large amount of refractory DON from forest soils and exhibited DON degradation rates of 82% and 71% for the hydrophilic and hydrophobic fractions, respectively. Amino acid contents and fluorescence intensities were also analyzed. Approximately 27% to 74% of amino acids were taken up by day 5, and their concentration gradually increased in the following days due to the decomposition of dissolved proteins. Parallel factor analysis resulted in identification of tryptophan-like proteins, tyrosine-like proteins and FA-like substances. During the growth phase, 40%-51% of the tryptophan-like proteins were taken up by bacteria, and the accumulation of tyrosine-like proteins was attributed to the release of biotic substances. The concentration of the FA-like substances decreased due to microbial decomposition.
authors.affiliation: School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China; State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Mingzhou
authors.initials: M
authors.lastname: Su
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Jingtian
authors.initials: J
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China. Electronic address: huoshouliang@126.com.
authors.forename: Shouliang
authors.initials: S
authors.lastname: Huo
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Beidou
authors.initials: B
authors.lastname: Xi
authors.affiliation: College of Environmental Science and Engineering, Anhui Normal University, Wuhu 241000, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Hua
authors.affiliation: College of Environmental Science and Engineering, Anhui Normal University, Wuhu 241000, China.
authors.forename: Fengyu
authors.initials: F
authors.lastname: Zan
authors.affiliation: School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China.
authors.forename: Guangren
authors.initials: G
authors.lastname: Qian
authors.affiliation: School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China.
authors.forename: Jianyong
authors.initials: J
authors.lastname: Liu
mesh_terms: D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry* / Q000382:microbiology; D057927:Hydrophobic and Hydrophilic Interactions; D060106:Lakes / Q000737:chemistry / Q000382:microbiology; D009584:Nitrogen / Q000032:analysis*; D014865:Waste Disposal, Fluid; D062065:Wastewater; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D009584:Nitrogen; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Amino acids; Dissolved organic nitrogen (DON); Microbial bioavailability; PARAFAC; Sediment