scholarly journals Metagenomics-guided analysis of microbial chemolithoautotrophic phosphite oxidation yields evidence of a seventh natural CO2fixation pathway

2017 ◽  
Vol 115 (1) ◽  
pp. E92-E101 ◽  
Author(s):  
Israel A. Figueroa ◽  
Tyler P. Barnum ◽  
Pranav Y. Somasekhar ◽  
Charlotte I. Carlström ◽  
Anna L. Engelbrektson ◽  
...  

Dissimilatory phosphite oxidation (DPO), a microbial metabolism by which phosphite (HPO32−) is oxidized to phosphate (PO43−), is the most energetically favorable chemotrophic electron-donating process known. Only one DPO organism has been described to date, and little is known about the environmental relevance of this metabolism. In this study, we used 16S rRNA gene community analysis and genome-resolved metagenomics to characterize anaerobic wastewater treatment sludge enrichments performing DPO coupled to CO2reduction. We identified an uncultivated DPO bacterium,CandidatusPhosphitivorax (Ca.P.) anaerolimi strain Phox-21, that belongs to candidate order GW-28 within theDeltaproteobacteria, which has no known cultured isolates. Genes for phosphite oxidation and for CO2reduction to formate were found in the genome ofCa.P. anaerolimi, but it appears to lack any of the known natural carbon fixation pathways. These observations led us to propose a metabolic model for autotrophic growth byCa.P. anaerolimi whereby DPO drives CO2reduction to formate, which is then assimilated into biomass via the reductive glycine pathway.

2020 ◽  
Vol 148 ◽  
pp. 01002
Author(s):  
Herto Dwi Ariesyady ◽  
Mentari Rizki Mayanda ◽  
Tsukasa Ito

Activated sludge process is one of the wastewater treatment method that is applied for many wastewater types including painting process wastewater of automotive industry. This wastewater is well-known to have high heavy metals concentration which could deteriorate water environment if appropriate performance of the wastewater treatment could not be achieved. In this study, we monitored microbial community diversity in a Painting Biological Treatment (PBT) system. We applied a combination of cultivation and genotypic biological methods based on 16S rRNA gene sequence analysis to identify the diversity of active microbial community. The results showed that active microbes that could grow in this activated sludge system were dominated by Gram-negative bacteria. Based on 16S rRNA gene sequencing analysis, it was revealed that their microbial diversity has close association with Bacterium strain E286, Isosphaera pallida, Lycinibacillus fusiformis, Microbacterium sp., Orchobactrum sp., Pseudomonas guariconensis, Pseudomonas sp. strain MR84, Pseudomonas sp. MC 54, Serpens sp., Stenotrophomonas acidaminiphila, and Xylella fastidiosa with similarity of 86 – 99%. This findings reflects that microbial community in a Painting Biological Treatment (PBT) system using activated sludge process could adapt with xenobiotics in the wastewater and has a wide range of diversity indicating a complex metabolism mechanism in the treatment process.


2001 ◽  
Vol 67 (11) ◽  
pp. 5273-5284 ◽  
Author(s):  
Holger Daims ◽  
Jeppe L. Nielsen ◽  
Per H. Nielsen ◽  
Karl-Heinz Schleifer ◽  
Michael Wagner

ABSTRACT Uncultivated Nitrospira-like bacteria in different biofilm and activated-sludge samples were investigated by cultivation-independent molecular approaches. Initially, the phylogenetic affiliation of Nitrospira-like bacteria in a nitrifying biofilm was determined by 16S rRNA gene sequence analysis. Subsequently, a phylogenetic consensus tree of theNitrospira phylum including all publicly available sequences was constructed. This analysis revealed that the genusNitrospira consists of at least four distinct sublineages. Based on these data, two 16S rRNA-directed oligonucleotide probes specific for the phylum and genus Nitrospira, respectively, were developed and evaluated for suitability for fluorescence in situ hybridization (FISH). The probes were used to investigate the in situ architecture of cell aggregates ofNitrospira-like nitrite oxidizers in wastewater treatment plants by FISH, confocal laser scanning microscopy, and computer-aided three-dimensional visualization. Cavities and a network of cell-free channels inside the Nitrospiramicrocolonies were detected that were water permeable, as demonstrated by fluorescein staining. The uptake of different carbon sources byNitrospira-like bacteria within their natural habitat under different incubation conditions was studied by combined FISH and microautoradiography. Under aerobic conditions, theNitrospira-like bacteria in bioreactor samples took up inorganic carbon (as HCO3 − or as CO2) and pyruvate but not acetate, butyrate, and propionate, suggesting that these bacteria can grow mixotrophically in the presence of pyruvate. In contrast, no uptake by theNitrospira-like bacteria of any of the carbon sources tested was observed under anoxic or anaerobic conditions.


2010 ◽  
Vol 60 (12) ◽  
pp. 2724-2728 ◽  
Author(s):  
Qiu-Xiang Yan ◽  
Yong-Xia Wang ◽  
Shun-Peng Li ◽  
Wen-Jun Li ◽  
Qing Hong

A Gram-staining-negative, catalase-positive, carbaryl-degrading, non-spore-forming, non-motile, rod-shaped bacterium, designated strain X23T, was isolated from a wastewater treatment system. Phylogenetic analysis based on 16S rRNA gene sequence indicated that the strain belongs to the genus Sphingobium. The highest 16S rRNA gene sequence similarity observed for the isolate was 96.6 % with the type strain of Sphingobium amiense. Chemotaxonomic data [major ubiquinone: Q-10; major polar lipids: diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol, sphingoglycolipid, phosphatidylethanolamine and unknown aminolipids and phospholipids; major fatty acids: summed feature 7 (C18 : 1 ω7c, C18 : 1 ω9t and/or C18 : 1 ω12t), C16 : 1 ω5c, C14 : 0 2-OH and C16 : 0 2-OH] as well as the inability to reduce nitrate and the presence of spermidine as the major polyamine supported the affiliation of the strain to the genus Sphingobium. Based on the phylogenetic analysis, whole-cell fatty acid composition and biochemical characteristics, the strain could be separated from all recognized species of the genus Sphingobium. Strain X23T should be classified as a novel species of the genus Sphingobium, for which the name Sphingobium qiguonii sp. nov. is proposed, with strain X23T (=CCTCC AB 208221T =DSM 21541T) as the type strain.


2009 ◽  
Vol 75 (11) ◽  
pp. 3673-3678 ◽  
Author(s):  
Farzaneh Rezaei ◽  
Defeng Xing ◽  
Rachel Wagner ◽  
John M. Regan ◽  
Tom L. Richard ◽  
...  

ABSTRACT Electricity can be directly generated by bacteria in microbial fuel cells (MFCs) from many different biodegradable substrates. When cellulose is used as the substrate, electricity generation requires a microbial community with both cellulolytic and exoelectrogenic activities. Cellulose degradation with electricity production by a pure culture has not been previously demonstrated without addition of an exogenous mediator. Using a specially designed U-tube MFC, we enriched a consortium of exoelectrogenic bacteria capable of using cellulose as the sole electron donor. After 19 dilution-to-extinction serial transfers of the consortium, 16S rRNA gene-based community analysis using denaturing gradient gel electrophoresis and band sequencing revealed that the dominant bacterium was Enterobacter cloacae. An isolate designated E. cloacae FR from the enrichment was found to be 100% identical to E. cloacae ATCC 13047T based on a partial 16S rRNA sequence. In polarization tests using the U-tube MFC and cellulose as a substrate, strain FR produced 4.9 ± 0.01 mW/m2, compared to 5.4 ± 0.3 mW/m2 for strain ATCC 13047T. These results demonstrate for the first time that it is possible to generate electricity from cellulose using a single bacterial strain without exogenous mediators.


2014 ◽  
Vol 64 (Pt_5) ◽  
pp. 1488-1494 ◽  
Author(s):  
Daichi Fujii ◽  
Fumiko Nagai ◽  
Yohei Watanabe ◽  
Yukio Shirasawa

Two Gram-staining-negative, strictly aerobic, non-endospore-forming, non-motile, rod-shaped bacteria, designated strains YIT 12745T and YIT 12746T, were isolated from sludge from a wastewater treatment plant. 16S rRNA gene sequence analyses indicated that these strains belonged to the genus Flavobacterium . In these analyses, strains YIT 12745T and YIT 12746T were most closely related to the type strains of Flavobacterium caeni and Flavobacterium terrigena , with 16S rRNA gene sequence similarity values of 94.9 % and 96.2 %, respectively. For both novel strains, menaquinone (MK-6) was the only respiratory quinone. The major fatty acids of strain YIT 12745T were iso-C15 : 1 G (14.4 %), iso-C16 : 0 (13.2 %), C15 : 0 (12.9 %), iso-C15 : 0 (12.9 %) and iso-C17 : 0 3-OH (11.5 %). Those of strain YIT 12746T were iso-C15 : 0 (21.5 %), iso-C16 : 0 (13.3 %), C15 : 0 (12.0 %) and iso-C15 : 1 G (11.9 %). The genomic DNA G+C contents of strains YIT 12745T and YIT 12746T were 48.7 and 30.9 mol%, respectively. From their differential phenotypic and phylogenetic characteristics, these strains are considered to represent two novel species of the genus Flavobacterium , for which the names Flavobacterium longum sp. nov. (type strain YIT 12745T = JCM 19141T = DSM 27077T) and Flavobacterium urocaniciphilum sp. nov. (type strain YIT 12746T = JCM 19142T = DSM 27078T) are proposed. Emended descriptions of Flavobacterium caeni and Flavobacterium terrigena are also proposed.


2010 ◽  
Vol 76 (17) ◽  
pp. 5902-5910 ◽  
Author(s):  
D. S. Jones ◽  
D. J. Tobler ◽  
I. Schaperdoth ◽  
M. Mainiero ◽  
J. L. Macalady

ABSTRACT We performed a microbial community analysis of biofilms inhabiting thermal (35 to 50°C) waters more than 60 m below the ground surface near Acquasanta Terme, Italy. The groundwater hosting the biofilms has 400 to 830 μM sulfide, <10 μM O2, pH of 6.3 to 6.7, and specific conductivity of 8,500 to 10,500 μS/cm. Based on the results of 16S rRNA gene cloning and fluorescent in situ hybridization (FISH), the biofilms have low species richness, and lithoautotrophic (or possibly mixotrophic) Gamma- and Epsilonproteobacteria are the principle biofilm architects. Deltaproteobacteria sequences retrieved from the biofilms have <90% 16S rRNA similarity to their closest relatives in public databases and may represent novel sulfate-reducing bacteria. The Acquasanta biofilms share few species in common with Frasassi cave biofilms (13°C, 80 km distant) but have a similar community structure, with representatives in the same major clades. The ecological success of Sulfurovumales-group Epsilonproteobacteria in the Acquasanta biofilms is consistent with previous observations of their dominance in sulfidic cave waters with turbulent water flow and high dissolved sulfide/oxygen ratios.


2015 ◽  
Vol 81 (20) ◽  
pp. 7067-7077 ◽  
Author(s):  
W. Ahmed ◽  
C. Staley ◽  
M. J. Sadowsky ◽  
P. Gyawali ◽  
J. P. S. Sidhu ◽  
...  

ABSTRACTIn this study, host-associated molecular markers and bacterial 16S rRNA gene community analysis using high-throughput sequencing were used to identify the sources of fecal pollution in environmental waters in Brisbane, Australia. A total of 92 fecal and composite wastewater samples were collected from different host groups (cat, cattle, dog, horse, human, and kangaroo), and 18 water samples were collected from six sites (BR1 to BR6) along the Brisbane River in Queensland, Australia. Bacterial communities in the fecal, wastewater, and river water samples were sequenced. Water samples were also tested for the presence of bird-associated (GFD), cattle-associated (CowM3), horse-associated, and human-associated (HF183) molecular markers, to provide multiple lines of evidence regarding the possible presence of fecal pollution associated with specific hosts. Among the 18 water samples tested, 83%, 33%, 17%, and 17% were real-time PCR positive for the GFD, HF183, CowM3, and horse markers, respectively. Among the potential sources of fecal pollution in water samples from the river, DNA sequencing tended to show relatively small contributions from wastewater treatment plants (up to 13% of sequence reads). Contributions from other animal sources were rarely detected and were very small (<3% of sequence reads). Source contributions determined via sequence analysis versus detection of molecular markers showed variable agreement. A lack of relationships among fecal indicator bacteria, host-associated molecular markers, and 16S rRNA gene community analysis data was also observed. Nonetheless, we show that bacterial community and host-associated molecular marker analyses can be combined to identify potential sources of fecal pollution in an urban river. This study is a proof of concept, and based on the results, we recommend using bacterial community analysis (where possible) along with PCR detection or quantification of host-associated molecular markers to provide information on the sources of fecal pollution in waterways.


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