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Jemaneh Habtewold, Robert Gordon, Vera Sokolov, Andrew VanderZaag, Claudia Wagner-Riddle, Kari Dunfield
Liquid dairy manure treated with sulfuric acid was stored in duplicate pilot-scale storage tanks for 120 days with continuous monitoring of CH4 emissions and concurrent examination of changes in the structure of bacterial and methanogenic communities. Methane emissions were monitored at the site using laser-based Trace Gas Analyzer whereas quantitative real-time polymerase chain reaction and massively parallel sequencing were employed to study bacterial and methanogenic communities using 16S rRNA and methyl-coenzyme M Reductase A ( mcrA ) genes/transcripts, respectively...
2018: Frontiers in Microbiology
Dipti D Nayak, William W Metcalf
Methanogenic archaea generate methane as a by-product of anaerobic respiration using CO2 , C1 compounds (like methanol or methylated amines), or acetate as terminal electron acceptors. Methanogens are an untapped resource for biotechnological advances related to methane production as well as methane consumption. However, key biological features of these organisms remain poorly understood. One such feature is the enzyme methyl-coenzyme M reductase (referred to as MCR), which catalyzes the last step in the methanogenic pathway and results in methane formation...
2018: Methods in Enzymology
Rubén M Buey, Ruth A Schmitz, Bob B Buchanan, Monica Balsera
The redox regulation of proteins via reversible dithiol/disulfide exchange reactions involves the thioredoxin system, which is composed of a reductant, a thioredoxin reductase (TR), and thioredoxin (Trx). In the pyridine nucleotide-dependent Trx reduction pathway, reducing equivalents, typically from reduced nicotinamide adenine dinucleotide phosphate (NADPH), are transferred from NADPH-TR (NTR) to Trx and, in turn, to target proteins, thus resulting in the reversible modification of the structural and functional properties of the targets...
November 17, 2018: Antioxidants (Basel, Switzerland)
Mengjiao Gao, Lei Zhang, Anna P Florentino, Yang Liu
Source-diverted blackwater (toilet wastewater) contains most of the organic energy in domestic wastewater and can be treated anaerobically to maximize energy recovery. Blackwater collected from toilets of different water saving options (e.g., conventional, dual and vacuum toilets) represents different characteristics, but their digestibility has not been discussed. In the present study, blackwater collected from different toilet flushing systems were characterized and compared in terms of chemical composition, digestibility and microbial population development during biochemical methane potential (BMP) tests...
October 25, 2018: Journal of Hazardous Materials
Mayur B Kurade, Shouvik Saha, El-Sayed Salama, Swapnil M Patil, Sanjay P Govindwar, Byong-Hun Jeon
Fats, oil and grease (FOG) are energy-dense wastes that substantially increase biomethane recovery. Shifts in the microbial community during anaerobic co-digestion of FOG was assessed to understand relationships between substrate digestion and microbial adaptations. Excessive addition of FOG inhibited the methanogenic activity during initial phase; however, it enhanced the ultimate methane production by 217% compared to the control. The dominance of Proteobacteria was decreased with a simultaneous increase in Firmicutes, Bacteriodetes, Synergistetes and Euryarchaeota during the co-digestion...
October 21, 2018: Bioresource Technology
Martin Alexander Fischer, Simon Güllert, Sarah Refai, Sven Künzel, Uwe Deppenmeier, Wolfgang R Streit, Ruth Anne Schmitz
Ammonia caused disturbance of biogas production is one of the most frequent incidents in regular operation of biogas reactors. This study provides a detailed insight into the microbial community of a mesophilic, full-scale biogas reactor (477 kWh h-1 ) fed with maize silage, dried poultry manure and cow manure undergoing initial process disturbance by increased ammonia concentration. Over a time period of 587 days, the microbial community of the reactor was regularly monitored on a monthly basis by high-throughput amplicon sequencing of the archaeal and bacterial 16S rRNA genes...
October 31, 2018: Microbial Biotechnology
Chun-Li Liu, Hao-Ran Bi, Zhonghu Bai, Li-Hai Fan, Tian-Wei Tan
Isoprene is a useful phytochemical with high commercial values in many industrial applications including synthetic rubber, elastomers, isoprenoid medicines, and fossil fuel. Currently, isoprene is on large scale produced from petrochemical sources. An efficient biological process for isoprene production utilizing renewable feedstocks would be an important direction of research due to the fossil raw material depletion and air pollution. In this study, we introduced the mevalonate (MVA) pathway genes/acetoacetyl-coenzyme A thiolase (mvaE) and MVA synthase (mvaS) from Enterococcus faecalis (E...
October 30, 2018: Applied Microbiology and Biotechnology
Miyako Shiraishi, Sonoko Ishino, Matthew Heffernan, Isaac Cann, Yoshizumi Ishino
Cytosine deamination into uracil is one of the most prevalent and pro-mutagenic forms of damage to DNA. Base excision repair is a well-known process of uracil removal in DNA, which is achieved by uracil DNA glycosylase (UDG) that is found in all three domains of life. However, other strategies for uracil removal seem to have been evolved in Archaea. Exonuclease III (ExoIII) from the euryarchaeon Methanothermobacter thermautotrophicus has been described to exhibit endonuclease activity toward uracil-containing DNA...
October 25, 2018: Scientific Reports
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 noncanonical 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...
November 16, 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...
February 15, 2019: 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
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