Description of microbial community structure of sediments from the Daliao River water system and its estuary (NE China) by application of fluorescence in situ hybridization

2010 ◽  
Vol 61 (8) ◽  
pp. 1725-1734 ◽  
Author(s):  
Xiangchun Quan ◽  
Yulai Wang ◽  
Weicong Xiong ◽  
Mengchang He ◽  
Zhifeng Yang ◽  
...  
2004 ◽  
Vol 49 (11-12) ◽  
pp. 61-68 ◽  
Author(s):  
T. Kindaichi ◽  
S. Okabe ◽  
H. Satoh ◽  
Y. Watanabe

Effects of hydroxylamine (NH2OH), an intermediate of NH4+ oxidation, on microbial community structure and function of two autotrophic nitrifying biofilms fed with and without NH2OH were analyzed by a 16S rRNA approach and the use of microelectrodes. In the NH2OH-added biofilm, partial oxidation of NH4+ to NO2- was observed, whereas complete oxidation of NH4+ to NO3- was achieved in the control biofilm. In situ hybridization results revealed that no nitrite-oxidizing bacteria (NOB) hybridized with any specific probes were detected in the NH2OH-added biofilm. Thus, the addition of low concentrations of NH2OH (250 mM) completely inhibited the growth of NOB. Phylogenetic analysis of 16S rDNA indicated that the ammonia-oxidizing bacteria (AOB) detected in both biofilms were closely related to Nitrosomonas europaea, and that the clone sequences from both biofilm libraries have more than 99% similarity to each other. However, in situ hybridization results revealed that the addition of NH2OH changed the form of growth pattern of the dominant Nitrosomonas spp. from dense clusters mode to single scattered cells mode. Microelectrode measurements revealed that the average NH4+ consumption rate calculated in the NH2OH-added biofilm was two times higher than that in the control biofilm. This clearly demonstrated that the oxidation of NH4+ was stimulated by NH2OH addition.


2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Huirong Lin ◽  
Shuting Zhang ◽  
Song Gong ◽  
Shenghua Zhang ◽  
Xin Yu

The composition and microbial community structure of the drinking water system biofilms were investigated using microstructure analysis and 454 pyrosequencing technique in Xiamen city, southeast of China. SEM (scanning electron microscope) results showed different features of biofilm morphology in different fields of PVC pipe. Extracellular matrix material and sparse populations of bacteria (mainly rod-shaped and coccoid) were observed. CLSM (confocal laser scanning microscope) revealed different distributions of attached cells, extracellular proteins,α-polysaccharides, andβ-polysaccharides. The biofilms had complex bacterial compositions. Differences in bacteria diversity and composition from different tap materials and ages were observed. Proteobacteria was the common and predominant group in all biofilms samples. Some potential pathogens (Legionellales, Enterobacteriales, Chromatiales, and Pseudomonadales) and corrosive microorganisms were also found in the biofilms. This study provides the information of characterization and visualization of the drinking water biofilms matrix, as well as the microbial community structure and opportunistic pathogens occurrence.


Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 507 ◽  
Author(s):  
Santisak Kitjanukit ◽  
Kyohei Takamatsu ◽  
Naoko Okibe

Natural attenuation of Mn(II) was observed inside the metal refinery wastewater pipeline, accompanying dark brown-colored mineralization (mostly MnIVO2 with some MnIII2O3 and Fe2O3) on the inner pipe surface. The Mn-deposit hosted the bacterial community comprised of Hyphomicrobium sp. (22.1%), Magnetospirillum sp. (3.2%), Geobacter sp. (0.3%), Bacillus sp. (0.18%), Pseudomonas sp. (0.03%), and non-metal-metabolizing bacteria (74.2%). Culture enrichment of the Mn-deposit led to the isolation of a new heterotrophic Mn(II)-oxidizer Pseudomonas sp. SK3, with its closest relative Ps. resinovorans (with 98.4% 16S rRNA gene sequence identity), which was previously unknown as an Mn(II)-oxidizer. Oxidation of up to 100 mg/L Mn(II) was readily initiated and completed by isolate SK3, even in the presence of high contents of MgSO4 (a typical solute in metal refinery wastewaters). Additional Cu(II) facilitated Mn(II) oxidation by isolate SK3 (implying the involvement of multicopper oxidase enzyme), allowing a 2-fold greater Mn removal rate, compared to the well-studied Mn(II)-oxidizer Ps. putida MnB1. Poorly crystalline biogenic birnessite was formed by isolate SK3 via one-electron transfer oxidation, gradually raising the Mn AOS (average oxidation state) to 3.80 in 72 h. Together with its efficient in vitro Mn(II) oxidation behavior, a high Mn AOS level of 3.75 was observed with the pipeline Mn-deposit sample collected in situ. The overall results, including the microbial community structure analysis of the pipeline sample, suggest that the natural Mn(II) attenuation phenomenon was characterized by robust in situ activity of Mn(II) oxidizers (including strain SK3) for continuous generation of Mn(IV). This likely synergistically facilitated chemical Mn(II)/Mn(IV) synproportionation for effective Mn removal in the complex ecosystem established in this artificial pipeline structure. The potential utility of isolate SK3 is illustrated for further industrial application in metal refinery wastewater treatment processes.


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