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Daniela López, Mario Sepúlveda-Mardones, Nathaly Ruiz-Tagle, Katherine Sossa, Enrica Uggetti, Gladys Vidal
Organic matter removal in a horizontal subsurface flow constructed wetland (HSSF) treating wastewater is associated with the presence of bacteria and archaea. These organisms perform anaerobic microbial processes such as methanogenesis, which can lead to methane emissions. The aim of this study was to evaluate methane production and characterize the bacterial and archaeal communities found in HSSFs treating secondary urban wastewater during cold and warm seasons. The pilot system used in this study corresponds to four HSSFs, two planted with Phragmites australis (HSSF-Phr) and two planted with Schoenoplectus californicus (HSSF-Sch), the monitoring was carried out for 1335 days...
January 15, 2019: Science of the Total Environment
David Ribas, Isabel Soares-Silva, Daniel Vieira, Maria Sousa-Silva, Joana Sá-Pessoa, João Azevedo-Silva, Sandra Cristina Viegas, Cecília Maria Arraiano, George Diallinas, Sandra Paiva, Pedro Soares, Margarida Casal
Organic acids are recognized as one of the most prevalent compounds in ecosystems, thus the transport and assimilation of these molecules represent an adaptive advantage for organisms. The AceTr family members are associated with the active transport of organic acids, namely acetate and succinate. The phylogenetic analysis shows this family is dispersed in the tree of life. However, in eukaryotes, it is almost limited to microbes, though reaching a prevalence close to 100% in fungi, with an essential role in spore development...
October 16, 2018: Fungal Genetics and Biology: FG & B
Zuopeng Lv, Athaydes Francisco Leite, Hauke Harms, Karin Glaser, Jan Liebetrau, Sabine Kleinsteuber, Marcell Nikolausz
Anaerobic digestion of nitrogen-rich substrate often causes process inhibition due to the susceptibility of the microbial community facing ammonia accumulation. However, the precise response of the microbial community has remained largely unknown. To explore the reasons, bacterial communities in ammonia-stressed reactors and control reactors were studied by amplicon pyrosequencing of 16S rRNA genes and the active methanogens were followed by terminal restriction fragment length polymorphism (T-RFLP) analyses of mcrA/mrtA gene transcripts...
October 17, 2018: Applied Microbiology and Biotechnology
Fabian Bonk, Denny Popp, Sören Weinrich, Heike Sträuber, Sabine Kleinsteuber, Hauke Harms, Florian Centler
Background: Demand-driven biogas production could play an important role for future sustainable energy supply. However, feeding a biogas reactor according to energy demand may lead to organic overloading and, thus, to process failures. To minimize this risk, digesters need to be actively steered towards containing more robust microbial communities. This study focuses on acetogenesis and methanogenesis as crucial process steps for avoiding acidification. We fed lab-scale anaerobic digesters with volatile fatty acids under various feeding regimes and disturbances...
2018: Biotechnology for Biofuels
Sabrina Beckmann, Alison W S Luk, Maria-Luisa Gutierrez-Zamora, Nur Hazlin Hazrin Chong, Torsten Thomas, Matthew Lee, Michael Manefield
Despite the significance of biogenic methane generation in coal beds, there has never been a systematic long-term evaluation of the ecological response to biostimulation for enhanced methanogenesis in situ. Biostimulation tests in a gas-free coal seam were analysed over 1.5 years encompassing methane production, cell abundance, planktonic and surface associated community composition and chemical parameters of the coal formation water. Evidence is presented that sulfate reducing bacteria are energy limited whilst methanogenic archaea are nutrient limited...
October 15, 2018: ISME Journal
Hailin Tian, Laura Treu, Konstantinos Konstantopoulos, Ioannis A Fotidis, Irini Angelidaki
Different mesophilic and thermophilic methanogenic consortia were acclimatised and enriched to extreme total ammonia (9.0 and 5.0 g NH4 + -N L-1 , respectively) and free ammonia (1.0 and 1.4 g NH3 -N L-1 , respectively) levels in this study. [2-14 C] acetate radioisotopic analyses showed the dominance of aceticlastic methanogenesis in all enriched consortia. According to 16S rRNA gene sequencing result, in mesophilic consortia, methylotrophic Methanomassiliicoccus luminyensis was predominant, followed by aceticlastic Methanosarcina soligelidi...
September 26, 2018: Bioresource Technology
Ali Ramezani, Thomas D Nolin, Ian R Barrows, Myrna G Serrano, Gregory A Buck, Renu Regunathan-Shenk, Raymond E West, Patricia S Latham, Richard Amdur, Dominic S Raj
A mechanistic link between trimethylamine N-oxide (TMAO) and atherogenesis has been reported. TMAO is generated enzymatically in the liver by the oxidation of trimethylamine (TMA), which is produced from dietary choline, carnitine and betaine by gut bacteria. It is known that certain members of methanogenic archaea (MA) could use methylated amines such as trimethylamine as growth substrates in culture. Therefore, we investigated the efficacy of gut colonization with MA on lowering plasma TMAO concentrations...
October 3, 2018: Scientific Reports
Fabien Lacombat, Agathe Espagne, Nadia Dozova, Pascal Plaza, Elisabeth Ignatz, Stephan Kiontke, Lars-Oliver Essen
Class II photolyases utilize for the photoreduction of their flavin cofactor (FAD) a completely different tryptophan triad than most other photolyases and cryptochromes. To counter sped-up back electron transfer, they evolved an unusually fast deprotonation of the distal tryptophanyl radical cation (WH˙+) that is produced after excitation of the flavin. We studied the primary aspects of oxidized FAD photoreduction by ultrafast transient absorption spectroscopy, using the class II photolyase from Methanosarcina mazei...
October 10, 2018: Physical Chemistry Chemical Physics: PCCP
Václav Beránek, Julian C W Willis, Jason W Chin
We recently characterized a new class of pyrrolysyl-tRNA synthetase (PylRS)/Pyl tRNA pairs from Methanomassiliicocales that are active and orthogonal in Escherichia coli. The aminoacyl-tRNA synthetases (aaRSs) of these pairs lack the N-terminal domain that is essential for tRNA recognition and in vivo activity in the Methanosarcina mazei ( Mm) PylRS but share a homologous active site with MmPylRS; this facilitates the transplantation of mutations discovered with existing PylRS systems into the new PylRS systems to reprogram their substrate specificity for the incorporation of noncanonical amino acids (ncAAs)...
September 27, 2018: Biochemistry
Birthe Meineke, Johannes Heimgärtner, Lorenzo Lafranchi, Simon J Elsässer
Genetic code expansion via stop codon suppression is a powerful technique for engineering proteins in mammalian cells with site-specifically encoded non-canonical amino acids (ncAAs). Current methods rely on very few available tRNA/aminoacyl-tRNA synthetase pairs orthogonal in mammalian cells, the pyrrolysyl tRNA/aminoacyl-tRNA synthetase pair from Methanosarcina mazei (Mma PylRS/PylT) being the most active and versatile to date. We found a pyrrolysyl tRNA/aminoacyl-tRNA synthetase pair from the human gut archaeon Methanomethylophilus alvus Mx1201 (Mx1201 PylRS/PylT) to be active and orthogonal in mammalian cells...
September 27, 2018: ACS Chemical Biology
Xiaojing Li, Yue Li, Xiaolin Zhang, Xiaodong Zhao, Yang Sun, Liping Weng, Yongtao Li
Biochar is extensively applied in amendment of contaminated soils. However, the effect of biochar on the biodegradation of petroleum hydrocarbons and electricity generation in soil microbial fuel cells (MFCs) remains unclear. Here, three biochars respectively derived from poultry (chicken manure, CB), agriculture (wheat straw, SB) and forestry industries (wood sawdust, WB) were investigated after 223 days of amendment. Consequently, high removal for alkanes was in CB with the mineral nutrition and phosphorus while aromatics were in SB with the most N content and the highest molecular polarity...
September 8, 2018: Science of the Total Environment
Hadi Nazem-Bokaee, Costas D Maranas
The abundance of methane in shale gas and of other gases such as carbon monoxide, hydrogen, and carbon dioxide as chemical process byproducts has motivated the use of gas fermentation for bioproduction. Recent advances in metabolic engineering and synthetic biology allow for engineering of microbes metabolizing a variety of chemicals including gaseous feeds into a number of biorenewables and transportation liquid fuels. New computational tools enable the systematic exploration of all feasible conversion alternatives...
2018: Frontiers in Microbiology
Jiajia Li, Leilei Xiao, Shiling Zheng, Yuechao Zhang, Min Luo, Chuan Tong, Hengduo Xu, Yang Tan, Juan Liu, Oumei Wang, Fanghua Liu
Conductive materials/minerals can promote direct interspecies electron transfer (DIET) between syntrophic bacteria and methanogens in defined co-culture systems and artificial anaerobic digesters; however, little is known about the stimulation strategy of carbon material on methane production in natural environments. Herein, the effect of carbon cloth, as a representative of conductive carbon materials, on methane production with incubated wetland soil was investigated. Carbon cloth significantly promoted methanogenesis...
December 1, 2018: Science of the Total Environment
Wenjie Zhang, Fangbiao Liu, Dunqiu Wang, Yue Jin
In this study, an anaerobic flat-sheet ceramic membrane bioreactor (AnCMBR) was used to treat high-strength dyeing wastewater, and compared with an upflow anaerobic sludge blanket (UASB) reactor. The start-up phases of the AnCMBR and UASB reactor were accomplished within 60 d by using cultivated seed sludge. The results showed that the AnCMBR had better COD, TN, and TP removal rates than the UASB reactor. The CH4 production of the AnCMBR was higher than that of the UASB reactor. The AnCMBR was operated with low energy consumption due to good water permeability of the flat-sheet ceramic membrane...
December 2018: Bioresource Technology
Lisa Nickel, Andrea Ulbricht, Omer S Alkhnbashi, Konrad U Förstner, Liam Cassidy, Katrin Weidenbach, Rolf Backofen, Ruth A Schmitz
The clustered regularly interspaced short palindromic repeat (CRISPR) system is a prokaryotic adaptive defense system against foreign nucleic acids. In the methanoarchaeon Methanosarcina mazei Gö1, two types of CRISPR-Cas systems are present (type I-B and type III-C). Both loci encode a Cas6 endonuclease, Cas6b-IB and Cas6b-IIIC, typically responsible for maturation of functional short CRISPR RNAs (crRNAs). To evaluate potential cross cleavage activity, we biochemically characterized both Cas6b proteins regarding their crRNA binding behavior and their ability to process pre-crRNA from the respective CRISPR array in vivo...
September 13, 2018: RNA Biology
Guoping Ren, Andong Hu, Shaofu Huang, Jie Ye, Jiahuan Tang, Shungui Zhou
The stimulatory effect of conductive particles on anaerobic digestion has been demonstrated in recent years. However, it is yet to be determined whether and how conductive particles affect methanogenesis via electro-fermentation (electro-fermentation methanogenesis). In this study, it was demonstrated, for the first time, that conductive graphite boosted the methane production yield by 54.3% and increased the maximum methane production rate by 72.2% during electro-fermentation methanogenesis. Graphite significantly affected the composition of cathode biofilms, with more live and large aggregates being observed...
December 2018: Bioresource Technology
Nina Lackner, Anna Hintersonnleitner, Andreas Otto Wagner, Paul Illmer
Although Methanosarcinales are versatile concerning their methanogenic substrates, the ability of Methanosarcina thermophila to use carbon dioxide (CO2 ) for catabolic and anabolic metabolism was not proven until now. Here, we show that M. thermophila used CO2 to perform hydrogenotrophic methanogenesis in the presence as well as in the absence of methanol. During incubation with hydrogen, the methanogen utilized the substrates methanol and CO2 consecutively, resulting in a biphasic methane production. Growth exclusively from CO2 occurred slowly but reproducibly with concomitant production of biomass, verified by DNA quantification...
2018: Archaea: An International Microbiological Journal
Gilberto Martins, Andreia F Salvador, Luciana Pereira, M Madalena Alves
Conductive materials (CM) have been extensively reported to enhance methane production in anaerobic digestion processes. The occurrence of direct interspecies electron transfer (DIET) in microbial communities, as an alternative or complementary to indirect electron transfer (via hydrogen or formate), is the main explanation given to justify the improvement of methane production. Not disregarding that DIET can be promoted in the presence of certain CM, it surely does not explain all the reported observations...
September 18, 2018: Environmental Science & Technology
Juntao Cui, Yanan Li, Chengyu Wang, Kyung Seok Kim, Tianye Wang, Shuxia Liu
The characteristics of the rhizosphere microbial community across different cultivation years (from 1, 3, 5, 15, 20, and 50 years) in saline-alkaline paddy soils in Songnen Plain of China were investigated based on sequence variation of 16S rDNA using Illumina MiSeq sequencing. The results showed that the microbial community diversity varied across cultivation years, showing higher diversity in cultivation years >15 than in cultivation years <15. The dominant microbial community of the rhizosphere was mainly composed of Proteobacteria, Acidobacteria, Firmicutes, and Bacteroidetes...
August 16, 2018: Canadian Journal of Microbiology
Dewang Kong, Keqiang Zhang, Junfeng Liang, Wenxuan Gao, Lianzhu Du
Three anaerobic reactors using pig manure (PM), maize straw (MS), and a mixture of the two as substrates were compared for archaeal community structure and diversity, and for methanogens response to increased organic loading rate (OLR, expressed in the mass of volatile solid (VS)). Methanogenic archaeal richness during codigestion of pig manure with maize straw (ACE: 2412) was greater than that during the others (ACE: 1225, 1467) at an OLR of 4 g L-1  day-1 , accompanied by high specific methane yield. Euryarchaeota and Crenarchaeota predominated during overall digestion of different substrates; with relative abundances of 63...
August 15, 2018: MicrobiologyOpen
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