title: Molecular analysis of halophilic bacterial community for high-rate denitrification of saline industrial wastewater.
abstract: A denitrification system for saline wastewater utilizing halophilic denitrifying bacteria has not been developed so far. In this study, denitrification performance and microbial community under various saline conditions were investigated using denitrifying sludge acclimated under low-salinity condition for a few years as seed sludge. A continuous denitrification experiment showed that denitrification performance and microbial community at 10% salinity was higher than that at 1% salinity. The microbial community in the denitrification sludge that was acclimated under low salinity was monitored by terminal-restriction fragment length polymorphism (T-RFLP) analysis during acclimation to high-salinity condition. T-RFLP profiles and clone analysis based on 16S rRNA-encoding genes in the sludge of the denitrification system with 10% salinity indicated that the gamma-Proteobacteria, particularly Halomonas spp., were predominant species, suggesting that these bacterial members were possibly responsible for a high denitrification activity under high-salinity conditions. Furthermore, the investigation of denitrification performance under various saline conditions revealed that 4-10% salinity results in the highest denitrification rate, indicating that this salinity was optimal for predominant bacterial species to exhibit denitrification activity. These results indicate the possibility that an appropriate denitrification system for saline wastewater can be designed using acclimated sludge with a halophilic community.
authors.affiliation: Department of Chemical Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo, 169-8555, Japan.
authors.forename: Sachiko
authors.initials: S
authors.lastname: Yoshie
authors.affiliation: Department of Chemical Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo, 169-8555, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Makino
authors.affiliation: Department of Chemical Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo, 169-8555, Japan.
authors.forename: Hidenobu
authors.initials: H
authors.lastname: Hirosawa
authors.affiliation: Department of Chemical Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo, 169-8555, Japan.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Shirotani
authors.affiliation: Department of Chemical Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo, 169-8555, Japan. stsuneda@waseda.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tsuneda
authors.affiliation: Department of Chemical Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo, 169-8555, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Hirata
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000378:metabolism*; D044822:Biodiversity; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D020563:Gammaproteobacteria / Q000302:isolation & purification; D020632:Halomonas / Q000302:isolation & purification; D007220:Industrial Waste; D008969:Molecular Sequence Data; D009584:Nitrogen / Q000378:metabolism*; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012462:Saline Solution, Hypertonic; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D012722:Sewage / Q000382:microbiology; D012965:Sodium Chloride; D013997:Time Factors; D014871:Water Microbiology
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D007220:Industrial Waste; D012336:RNA, Ribosomal, 16S; D012462:Saline Solution, Hypertonic; D012722:Sewage; D012965:Sodium Chloride; D009584:Nitrogen