No Barriers to Cellulose Breakdown

Science ◽  
2013 ◽  
Vol 342 (6165) ◽  
pp. 1454-1456 ◽  
Author(s):  
A. Berlin
Keyword(s):  
Cellulose Breakdown

Cellulose Breakdown

2014 ◽  
Vol 081 (06) ◽  
Author(s):  
John Greenler ◽  
Leith Nye ◽  
Travis Tangen
Keyword(s):  
Cellulose Breakdown

scholarly journals Lignocellulosic Composites Prepared Utilizing Aqueous Alkaline/Urea Solutions with Cold Temperatures

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Brent Tisserat ◽  
Zengshe Liu ◽  
Luke M. Haverhals
Keyword(s):  
Mechanical Properties ◽  
Cotton Wool ◽  
Cold Temperatures ◽  
Osage Orange ◽  
Aqueous Solvent ◽  
The Matrix ◽  
Cellulose Breakdown ◽  
Matrix Concentration ◽  
Solvent Volume ◽  
Agave Fibers

Lignocellulosic composites (LCs) were fabricated by partially dissolving cotton to create a matrix that was reinforced with osage orange wood (OOW) particles and/or blue agave fibers (AF). LCs were composed of 15–35% cotton matrix and 65–85% OWW/AF reinforcement. The matrix was produced by soaking cotton wool in a cold aqueous alkaline/urea solvent and was stirred for 15 minutes at 350 rpm to create a viscous gel. The gel was then reinforced with lignocellulosic components, mixed, and then pressed into a panel mold. LC panels were soaked in water to remove the aqueous solvent and then oven dried to obtain the final LC product. Several factors involved in the preparation of these LCs were examined including reaction temperatures (−5 to −15°C), matrix concentration (15–35% cotton), aqueous solvent volume (45–105 ml/panel), and the effectiveness of employing various aqueous solvent formulations. The mechanical properties of LCs were determined and reported. Conversion of the cotton into a suitable viscous gel was critical in order to obtain LCs that exhibited high mechanical properties. LCs with the highest mechanical properties were obtained when the cotton wools were subjected to a 4.6% LiOH/15% urea solvent at −12.5°C using an aqueous solvent volume of 60 ml/panel. Cotton wool subjected to excessive cold alkaline solvents volumes resulted in irreversible cellulose breakdown and a resultant LC that exhibited poor mechanical properties.

scholarly journals Importance of Defluviitalea raffinosedens for Hydrolytic Biomass Degradation in Co-Culture with Hungateiclostridium thermocellum

2020 ◽  
Vol 8 (6) ◽  
pp. 915
Author(s):  
Regina Rettenmaier ◽  
Martina Schneider ◽  
Bernhard Munk ◽  
Michael Lebuhn ◽  
Sebastian Jünemann ◽  
...  
Keyword(s):  
Plant Biomass ◽  
Cellulose Hydrolysis ◽  
Taxonomic Composition ◽  
Process Conditions ◽  
Cellulose Breakdown ◽  
Metabolic Properties ◽  
Reactor Operating ◽  
First Time ◽  
Hydrolysis Of

Bacterial hydrolysis of polysaccharides is an important step for the production of sustainable energy, for example during the conversion of plant biomass to methane-rich biogas. Previously, Hungateiclostridium thermocellum was identified as cellulolytic key player in thermophilic biogas microbiomes with a great frequency as an accompanying organism. The aim of this study was to physiologically characterize a recently isolated co-culture of H. thermocellum and the saccharolytic bacterium Defluviitalea raffinosedens from a laboratory-scale biogas fermenter. The characterization focused on cellulose breakdown by applying the measurement of cellulose hydrolysis, production of metabolites, and the activity of secreted enzymes. Substrate degradation and the production of volatile metabolites was considerably enhanced when both organisms acted synergistically. The metabolic properties of H. thermocellum have been studied well in the past. To predict the role of D. raffinosedens in this bacterial duet, the genome of D. raffinosedens was sequenced for the first time. Concomitantly, to deduce the prevalence of D. raffinosedens in anaerobic digestion, taxonomic composition and transcriptional activity of different biogas microbiomes were analyzed in detail. Defluviitalea was abundant and metabolically active in reactor operating at highly efficient process conditions, supporting the importance of this organism for the hydrolysis of the raw substrate.

scholarly journals Dampening the DAMPs: How Plants Maintain the Homeostasis of Cell Wall Molecular Patterns and Avoid Hyper-Immunity

2020 ◽  
Vol 11 ◽  
Author(s):  
Daniela Pontiggia ◽  
Manuel Benedetti ◽  
Sara Costantini ◽  
Giulia De Lorenzo ◽  
Felice Cervone
Keyword(s):  
Plant Immunity ◽  
Microbial Pathogens ◽  
General Strategy ◽  
Plant Cell Walls ◽  
Cellular Mechanisms ◽  
The Family ◽  
Cellulose Breakdown ◽  
Molecular Patterns ◽  
Damage Associated Molecular Patterns ◽  
Hydrolysis Of

Several oligosaccharide fragments derived from plant cell walls activate plant immunity and behave as typical damage-associated molecular patterns (DAMPs). Some of them also behave as negative regulators of growth and development, and due to their antithetic effect on immunity and growth, their concentrations, activity, time of formation, and localization is critical for the so-called “growth-defense trade-off.” Moreover, like in animals, over accumulation of DAMPs in plants provokes deleterious physiological effects and may cause hyper-immunity if the cellular mechanisms controlling their homeostasis fail. Recently, a mechanism has been discovered that controls the activity of two well-known plant DAMPs, oligogalacturonides (OGs), released upon hydrolysis of homogalacturonan (HG), and cellodextrins (CDs), products of cellulose breakdown. The potential homeostatic mechanism involves specific oxidases belonging to the family of berberine bridge enzyme-like (BBE-like) proteins. Oxidation of OGs and CDs not only inactivates their DAMP activity, but also makes them a significantly less desirable food source for microbial pathogens. The evidence that oxidation and inactivation of OGs and CDs may be a general strategy of plants for controlling the homeostasis of DAMPs is discussed. The possibility exists of discovering additional oxidative and/or inactivating enzymes targeting other DAMP molecules both in the plant and in animal kingdoms.

Indirect evidence for cellulase production by Rhizobium in pea root nodules during bacteroid differentiation: cytochemical aspects of cellulose breakdown in rhizobial droplets

1989 ◽  
Vol 35 (9) ◽  
pp. 821-829 ◽  
Author(s):  
François-P. Chalifour ◽  
Nicole Benhamou
Keyword(s):  
Rhizobium Leguminosarum ◽  
Root Nodules ◽  
Hydrolytic Enzyme ◽  
Indirect Evidence ◽  
Cellulase Production ◽  
Cytochemical Localization ◽  
Thin Walls ◽  
Sequence Of Events ◽  
Infection Threads ◽  
Cellulose Breakdown

Cytochemical localization of cellulosic β-(1–4) glucans in pea (Pisum sativum L.) nodules at different stages of infection by an effective isolate of Rhizobium leguminosarum biovar viceae was studied using a gold-complexed exoglucanase. Cellulose subunits were present in great amounts in root cell walls, as shown by intense and regular labeling by gold particles. Labeling was unevenly distributed over the thin walls of emerging infection threads. In more developed infection threads, labeling was more intense and evenly distributed than in emerging threads, although slightly altered, unlabeled wall areas were frequently observed at the growing tips. Droplets containing rhizobia, which originated from infection threads, were surrounded by labeled wall-like material. Rhizobial droplets were either single- or multi-celled, and were sometimes separated by inner, unevenly labeled compartments. The surrounding wall-like material was irregularly labeled, and unlabeled wall areas, neighbouring intensely labeled ones, were observed frequently. There was an absence of labeling ahead of the rhizobia that escaped from the droplets, but degenerating wall-like material was present around the escaping rhizobia, mainly on their sides. At more advanced stages of development, labeling was present only over the outermost wall layers of rhizobial droplets, indicating that inner portions were degraded first. These observations suggest that a hydrolytic enzyme is involved in the sequence of events from infection thread formation through rhizobial release in the host cell cytoplasm, and that the hydrolytic enzyme is of rhizobial origin.Key words: Rhizobium–Pisum symbiosis, root nodules, rhizobial droplets, cellulose, colloidal gold.

scholarly journals Cellulose breakdown

2008 ◽  
Author(s):  
Neil Withers
Keyword(s):  
Cellulose Breakdown

scholarly journals High-Temperature Enzymatic Breakdown of Cellulose

2011 ◽  
Vol 77 (15) ◽  
pp. 5199-5206 ◽  
Author(s):  
Hongliang Wang ◽  
Fabio Squina ◽  
Fernando Segato ◽  
Andrew Mort ◽  
David Lee ◽  
...  
Keyword(s):  
Cell Wall ◽  
High Temperature ◽  
Cellulase Activity ◽  
Initial Activity ◽  
Glycosidic Bonds ◽  
Enzyme Substrate ◽  
Cellulose Breakdown ◽  
Temperature Operating ◽  
Temperature Optima ◽  
Wall Components

ABSTRACTCellulose is an abundant and renewable biopolymer that can be used for biofuel generation; however, structural entrapment with other cell wall components hinders enzyme-substrate interactions, a key bottleneck for ethanol production. Biomass is routinely subjected to treatments that facilitate cellulase-cellulose contacts. Cellulases and glucosidases act by hydrolyzing glycosidic bonds of linear glucose β-1,4-linked polymers, producing glucose. Here we describe eight high-temperature-operating cellulases (TCel enzymes) identified from a survey of thermobacterial and archaeal genomes. Three TCel enzymes preferentially hydrolyzed soluble cellulose, while two preferred insoluble cellulose such as cotton linters and filter paper. TCel enzymes had temperature optima ranging from 85°C to 102°C. TCel enzymes were stable, retaining 80% of initial activity after 120 h at 85°C. Two modes of cellulose breakdown, i.e., with endo- and exo-acting glucanases, were detected, and with two-enzyme combinations at 85°C, synergistic cellulase activity was observed for some enzyme combinations.

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