POLYSACCHARIDE DEGRADING ENZYMES IN MICROBIAL POPULATIONS FROM THE LIQUID AND SOLID FRACTIONS OF BOVINE RUMEN DIGESTA

1984 ◽  
Vol 64 (5) ◽  
pp. 58-59 ◽  
Author(s):  
A. G. WILLIAMS ◽  
N. H. STRACHAN
Keyword(s):  
Liquid Phase ◽  
Key Words ◽  
Glycoside Hydrolase ◽  
Microbial Populations ◽  
Bovine Rumen ◽  
Degrading Enzymes ◽  
The Stability

Polysaccharide depolymerase and glycoside hydrolase enzymes involved in the degradation of plant structural polysaccharides were most active in the adherent particle-associated microorganisms, whereas soluble saccharides were metabolized by the liquid phase and nonadherent populations. The activities were constant confirming the stability of the populations. Key words: Polysaccharidase, glycosidase, particle-associated microorganisms

scholarly journals Catalytic Performance of Nitrogen-Doped Activated Carbon Supported Pd Catalyst for Hydrodechlorination of 2,4-Dichlorophenol or Chloropentafluoroethane

Molecules ◽  
2019 ◽  
Vol 24 (4) ◽  
pp. 674 ◽  
Author(s):  
Haodong Tang ◽  
Bin Xu ◽  
Meng Xiang ◽  
Xinxin Chen ◽  
Yao Wang ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Liquid Phase ◽  
Gas Phase ◽  
Nitrogen Doping ◽  
Catalyst Surface ◽  
Catalytic Performance ◽  
Atomic Ratio ◽  
Pd Catalyst ◽  
Nitrogen Doped ◽  
The Stability

Nitrogen-doped activated carbon (N-AC) obtained through the thermal treatment of a mixture of HNO3-pretreated activated carbon (AC) and urea under N2 atmosphere at 600 °C was used as the carrier of Pd catalyst for both liquid-phase hydrodechlorination of 2,4-dichlorophenol (2,4-DCP) and gas-phase hydrodechlorination of chloropentafluoroethane (R-115). The effects of nitrogen doping on the dispersion and stability of Pd, atomic ratio of Pd/Pd2+ on the surface of the catalyzer, the catalyst’s hydrodechlorination activity, as well as the stability of N species in two different reaction systems were investigated. Our results suggest that, despite no improvement in the dispersion of Pd, nitrogen doping may significantly raise the atomic ratio of Pd/Pd2+ on the catalyst surface, with a value of 1.2 on Pd/AC but 2.2 on Pd/N-AC. Three types of N species, namely graphitic, pyridinic, and pyrrolic nitrogen, were observed on the surface of Pd/N-AC, and graphitic nitrogen was stable in both liquid-phase hydrodechlorination of 2,4-DCP and gas-phase hydrodechlorination of R-115, with pyridinic and pyrrolic nitrogen being unstable during gas-phase hydrodechlorination of R-115. As a result, the average size of Pd nanocrystals on Pd/N-AC was almost kept unchanged after liquid-phase hydrodechlorination of 2,4-DCP, whereas crystal growth of Pd was clearly observed on Pd/N-AC after gas-phase hydrodechlorination of R-115. The activity test revealed that Pd/N-AC exhibited a much better performance than Pd/AC in liquid-phase hydrodechlorination of 2,4-DCP, probably due to the enhanced stability of Pd exposed to the environment resulting from nitrogen doping as suggested by the higher atomic ratio of Pd/Pd2+ on the catalyst surface. In the gas-phase hydrodechlorination of R-115, however, a more rapid deactivation phenomenon occurred on Pd/N-AC than on Pd/AC despite a higher activity initially observed on Pd/N-AC, hinting that the stability of pyridinic and pyrrolic nitrogen plays an important role in the determination of catalytic performance of Pd/N-AC.

scholarly journals Screening of a Novel Glycoside Hydrolase Family 51 α-L-Arabinofuranosidase from Paenibacillus polymyxa KF-1: Cloning, Expression, and Characterization

Catalysts ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 589 ◽  
Author(s):  
Yanbo Hu ◽  
Yan Zhao ◽  
Shuang Tian ◽  
Guocai Zhang ◽  
Yumei Li ◽  
...  
Keyword(s):  
Glycoside Hydrolase ◽  
Synergistic Effects ◽  
Paenibacillus Polymyxa ◽  
Mass Spectrometry Analysis ◽  
Glycoside Hydrolase Family ◽  
Spectrometry Analysis ◽  
Degrading Enzymes ◽  
Wheat Arabinoxylan ◽  
Hydrolase Family ◽  
Glycoside Hydrolase Family 51

Paenibacillus polymyxa exhibits remarkable hemicellulolytic activity. In the present study, 13 hemicellulose-degrading enzymes were identified from the secreted proteome of P. polymyxa KF-1 by liquid chromatography-tandem mass spectrometry analysis. α-L-arabinofuranosidase is an important member of hemicellulose-degrading enzymes. A novel α-L-arabinofuranosidase (PpAbf51b), belonging to glycoside hydrolase family 51, was identified from P. polymyxa. Recombinant PpAbf51b was produced in Escherichia coli BL21 (DE3) and was found to be a tetramer using gel filtration chromatography. PpAbf51b hydrolyzed neutral arabinose-containing polysaccharides, including sugar beet arabinan, linear-1,5-α-L-arabinan, and wheat arabinoxylan, with L-arabinose as the main product. The products from hydrolysis indicate that PpAbf51b functions as an exo-α-L-arabinofuranosidase. Combining PpAbf51b and Trichoderma longibrachiatum endo-1,4-xylanase produced significant synergistic effects for the degradation of wheat arabinoxylan. The α-L-arabinofuranosidase identified from the secretome of P. polymyxa KF-1 is potentially suitable for application in biotechnological industries.

Insights into the stability and thermal properties of WSe2-based nanofluids for concentrating solar power prepared by liquid phase exfoliation

2020 ◽  
Vol 319 ◽  
pp. 114333
Author(s):  
Paloma Martínez-Merino ◽  
Antonio Sánchez-Coronilla ◽  
Rodrigo Alcántara ◽  
Elisa I. Martín ◽  
Javier Navas
Keyword(s):  
Thermal Properties ◽  
Liquid Phase ◽  
Solar Power ◽  
Concentrating Solar Power ◽  
Liquid Phase Exfoliation ◽  
The Stability

scholarly journals A catalog of microbial genes from the bovine rumen unveils a specialized and diverse biomass-degrading environment

GigaScience ◽  
2020 ◽  
Vol 9 (6) ◽  
Author(s):  
Junhua Li ◽  
Huanzi Zhong ◽  
Yuliaxis Ramayo-Caldas ◽  
Nicolas Terrapon ◽  
Vincent Lombard ◽  
...  
Keyword(s):  
Plant Cell Wall ◽  
Production Systems ◽  
Wall Material ◽  
Rumen Microbes ◽  
Bovine Rumen ◽  
Degrading Enzymes ◽  
Genes Encoding ◽  
Health And Disease ◽  
Metagenome Sequencing ◽  
Available Information

Abstract Background The rumen microbiota provides essential services to its host and, through its role in ruminant production, contributes to human nutrition and food security. A thorough knowledge of the genetic potential of rumen microbes will provide opportunities for improving the sustainability of ruminant production systems. The availability of gene reference catalogs from gut microbiomes has advanced the understanding of the role of the microbiota in health and disease in humans and other mammals. In this work, we established a catalog of reference prokaryote genes from the bovine rumen. Results Using deep metagenome sequencing we identified 13,825,880 non-redundant prokaryote genes from the bovine rumen. Compared to human, pig, and mouse gut metagenome catalogs, the rumen is larger and richer in functions and microbial species associated with the degradation of plant cell wall material and production of methane. Genes encoding enzymes catalyzing the breakdown of plant polysaccharides showed a particularly high richness that is otherwise impossible to infer from available genomes or shallow metagenomics sequencing. The catalog expands the dataset of carbohydrate-degrading enzymes described in the rumen. Using an independent dataset from a group of 77 cattle fed 4 common dietary regimes, we found that only <0.1% of genes were shared by all animals, which contrast with a large overlap for functions, i.e., 63% for KEGG functions. Different diets induced differences in the relative abundance rather than the presence or absence of genes, which explains the great adaptability of cattle to rapidly adjust to dietary changes. Conclusions These data bring new insights into functions, carbohydrate-degrading enzymes, and microbes of the rumen to complement the available information on microbial genomes. The catalog is a significant biological resource enabling deeper understanding of phenotypes and biological processes and will be expanded as new data are made available.

Postprandial variations in the activity of polysaccharide-degrading enzymes of fluid- and particle-associated ruminal microbial populations

1993 ◽  
Vol 27 (4) ◽  
pp. 223-228 ◽  
Author(s):  
Cécile Martin ◽  
Brigitte Michalet-Doreau ◽  
Gérard Fonty ◽  
Alan Williams
Keyword(s):  
Microbial Populations ◽  
Degrading Enzymes ◽  
Ruminal Microbial Populations

INDUCTION AND TRANSFER OF THE MICROBIAL CAPACITY TO DEGRADE NITROTOXINS IN THE RUMEN

1984 ◽  
Vol 64 (5) ◽  
pp. 33-34 ◽  
Author(s):  
W. MAJAK ◽  
K.-J. CHENG
Keyword(s):  
Key Words ◽  
Nitrate Reduction ◽  
Bovine Rumen

Nitrocompounds, given intraruminally, were tested as potential inducers of nitrate, nitrite and nitropropanol detoxification in the bovine rumen. Nitroethane supplements stimulated the microbial rate of nitropropanol degradation. Nitrate supplements increased the rates for nitrite and nitrate reduction and this induced capacity was transferred between groups of animals in adjacent pens. Key words: Cattle, nitrate, nitrite, nitropropanol, detoxification

scholarly journals Stressor Exposure Disrupts Commensal Microbial Populations in the Intestines and Leads to Increased Colonization by Citrobacter rodentium

2010 ◽  
Vol 78 (4) ◽  
pp. 1509-1519 ◽  
Author(s):  
Michael T. Bailey ◽  
Scot E. Dowd ◽  
Nicola M. A. Parry ◽  
Jeffrey D. Galley ◽  
David B. Schauer ◽  
...  
Keyword(s):  
Intestinal Microbiota ◽  
Microbial Populations ◽  
Enteric Infection ◽  
Citrobacter Rodentium ◽  
Necrosis Factor Alpha ◽  
Culture Techniques ◽  
Beneficial Effects ◽  
Amplicon Pyrosequencing ◽  
Pathogen Colonization ◽  
The Stability

ABSTRACT The gastrointestinal tract is colonized by an enormous array of microbes that are known to have many beneficial effects on the host. Previous studies have indicated that stressor exposure can disrupt the stability of the intestinal microbiota, but the extent of these changes, as well as the effects on enteric infection, has not been well characterized. In order to examine the ability of stressors to induce changes in the gut microbiota, we exposed mice to a prolonged restraint stressor and then characterized microbial populations in the intestines using both traditional culture techniques and bacterial tag-encoded FLX amplicon pyrosequencing (bTEFAP). Exposure to the stressor led to an overgrowth of facultatively anaerobic microbiota while at the same time significantly reducing microbial richness and diversity in the ceca of stressed mice. Some of these effects could be explained by a stressor-induced reduction in the relative abundance of bacteria in the family Porphyromonadaceae. To determine whether these alterations would lead to increased pathogen colonization, stressed mice, as well as nonstressed controls, were challenged orally with the enteric murine pathogen Citrobacter rodentium. Exposure to the restraint stressor led to a significant increase in C. rodentium colonization over that in nonstressed control mice. The increased colonization was associated with increased tumor necrosis factor alpha (TNF-α) gene expression in colonic tissue. Together, these data demonstrate that a prolonged stressor can significantly change the composition of the intestinal microbiota and suggest that this disruption of the microbiota increases susceptibility to an enteric pathogen.

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