Diversity of denitrifying bacteria in the sediments from Shiangshan Wetland
Date Issued
2008
Date
2008
Author(s)
Zhuang, Huan Chang
Abstract
Denitrifying bacteria are predominant species in global nitrogen cycle. Since many species can treat organic pollutant containing high nitrogen efficiently, so their contribution to environment was gaining attention by the microbial ecologists. This study was aimed to investigate the diversity of denitrifying bacteria in the sediments from Shiangshan Wetland. The soil samples were obtained from the coastal ecosystem near Koya Water Resource Recycling Center and Haishangu during years 2006 and 2007. After serial dilution, the samples were injected into PYN (polypepton-yeast-nitrate) broth medium, and then incubated under anaerobic condition. The abundance of denitrifying bacteria were calculated by the method of most-probable-number (MPN) in PYN broth, and the MPN values were found ranged from 2.9×103 to 4.6×107 cells/g wet wt.ixty-four denitrifying isolates are divided into twelve groups, according to the restriction fragment length polymorphisms (RFLP) analysis with three endonucleases, RsaI, DdeI and AluI. These bacteria are belonging to seven genera, among them Marinobacter and Halomonas were the major, according to phylogenetic analysis of 16S rDNA sequences of representative isolates.26 and N41 shared low identities of 16S rDNA sequence with the known species. However, the phylogeneic relationship between N26 and Oceanicola batsensis was closer than other known species, but the phenotypic properties of N26 were similar to Maritimibacter alkaliphilus. Furthermore, N26 was motile and facultative anaerobic, which differed from Oceanicola batsensis and Maritimibacter alkaliphilus. Strain N41 compared with other known species showed the highest 16S rDNA sequence identity of 97.3% with Marinobacter sediminum R65T. However, N41 was facultative anaerobic but M. sediminum was aerobic. Polyphasic data accumulated in this study revealed that the two denitrifying isolates could be classified as two novel species. Besides diversity and phylogenetic analysis of denitrifying bacteria, this study also used primer pairs in conserved regions of nitrite reductase gene (nirK and nirS) to determine the nir gene type of denitrifying isolates with PCR. Some isolates belong to Marinobacter and Idiomarina genera had nirS gene, and one isolate (N20) belong to Photobacterium genus had nirK gene. This nirK gene was sequenced and shared 78% amino acid identity to NirK of Shewanella loihica. Other six genotypic groups including Halomonas could not detect either of the Nir gene with these primer pairs.
Subjects
wetland
denitrifier
diversity
RFLP
bacteria
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-97-R95241216-1.pdf
Size
23.53 KB
Format
Adobe PDF
Checksum
(MD5):49c3432dbb4f87ac44652060908321a2