Microbial Community Analysis in the Denitrification Process of Saline-Wastewater by Denaturing Gradient Gel Electrophoresis of PCR-Amplified 16S rDNA and the Cultivation Method.

Abstract

The metallurgic wastewater generated from the processes of recovering precious metals from industrial wastes contains high concentrations of nitrogen compounds and salts. Biological nitrogen removal from this wastewater was attempted using a circulating bioreactor system equipped with an anaerobic packed bed or an anaerobic fluidized bed. The denitrification capability of the system with the anaerobic packed bed was more stable than that of the system with the anaerobic fluidized bed. The NOx removal rate of the anaerobic packed bed was as high as 97%. Microbial community analysis by denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S ribosomal DNA (rDNA) fragments and the cultivation method revealed that the community diversity varied in accordance with wastewater composition such as the level of salinity and so on. Phylogenetic analysis suggested that the taxonomic affiliation of the dominant species in the anaerobic reactors was to the gamma-Proteobacteria including Halomonadaceae species. The PCR-DGGE method as a non-cultivation method was found to be a powerful tool for analysis of the microbial community, because the cultivation method could detect only a fraction of the microbial species present in these systems. The genetic diversity of the isolated bacteria belonging to the gamma-Proteobacteria which reduced both nitrate and nitrite in the anaerobic packed bed was higher than that of the bacteria in the anaerobic fluidized bed. This suggested that a genetically diverse microbial community stabilized the denitrifying performance in the anaerobic packed bed.

Dynamic model for nitric oxide removal by a rotating drum biofilter

“…In NO elimination, the microorganism species in biofilm are complex [28,29], but can be assumed as one kind of microorganism according to the model developed by Grady et al [30]. The parameters of the model are therefore considered to be one kind of microorganism.…”

Characteristics of bacteria showing high denitrification activity in saline wastewater

“…The growth ability under saline conditions was evaluated by observing the formation of colonies. Furthermore, the 16S rRNA gene sequence of each isolated strain was determined according to our previous study (Yoshie et al 2001). A database search was conducted using BLAST (Altschul et al 1990) from DNA Data Bank of Japan (DDBJ).…”

“…Conversely, some bacterial strains have been isolated from denitrification systems, where saline wastewater diluted with tap water (salinity: 1-3% NaCl concentra-tion) inflowed (Yoshie et al 2001). The isolated strains are Gram-positive bacteria, Cytophaga-Flavobacterium, betaproteobacteria and mainly gammaproteobacteria including halophilic bacteria such as Halomonas sp., Colwellia sp.…”

Effect of hypersaline aniline-containing pharmaceutical wastewater on the structure of activated sludge-derived bacterial community

“…The bacteria in activated sludge are responsible for converting the harmful pollutants into harmless compounds before releasing the wastewater into the environment. For years, researchers have examined the microbial populations of these activated sludge communities in order to understand their specific biological processes [11][12][13][14][15]. Boon et al evaluated the bacterial communities of activated sludge samples that received wastewater from four different types of industries [10].…”