scholarly journals Sustainable polyesters via direct functionalization of lignocellulosic sugars

2021 ◽  
Author(s):  
Lorenz Manker ◽  
Graham Dick ◽  
Adrien Demongeot ◽  
Maxime Hédou ◽  
Christèle Rayroud ◽  
...  
Keyword(s):  
Material Properties ◽  
Glyoxylic Acid ◽  
Waste Streams ◽  
Direct Transformation ◽  
Glass Transition Temperatures ◽  
Biologically Relevant ◽  
Renewable Feedstocks ◽  
Melt Polycondensation ◽  
Direct Functionalization ◽  
Lignocellulosic Sugars

The development of sustainable plastics from abundant renewable feedstocks has been limited by the complexity and efficiency of their production as well as their lack of competitive material properties. Here, we demonstrate the direct transformation of the hemicellulosic fraction of non-edible biomass into a diester plastic precursor at 83% yield (95% from commercial xylose) during integrated plant fractionation with glyoxylic acid. Melt polycondensation of the resulting xylose-based diester with a range of aliphatic diols led to high-molecular weight amorphous polyesters with combined high glass transition temperatures, tough mechanical properties, and strong gas barriers, which could be processed by injection-molding, thermoforming, and 3D-printing. These polyesters could then be chemically recycled from mixed plastic waste streams or digested under biologically relevant conditions. The transformation’s simplicity led to projected costs that were competitive with fossil alternatives and significantly reduced associated greenhouse gas emissions, especially if glyoxylic acid was sourced from CO2.

scholarly journals Fermentation of Organic Residues to Beneficial Chemicals: A Review of Medium-Chain Fatty Acid Production

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1571
Author(s):  
Panagiota Stamatopoulou ◽  
Juliet Malkowski ◽  
Leandro Conrado ◽  
Kennedy Brown ◽  
Matthew Scarborough
Keyword(s):  
Organic Waste ◽  
Chain Elongation ◽  
Organic Substrates ◽  
Industrial Chemicals ◽  
Waste Streams ◽  
Fatty Acid Production ◽  
Medium Chain ◽  
Renewable Feedstocks ◽  
History Of ◽  
Complex Organic

Medium-chain fatty acids (MCFAs) have a variety of uses in the production of industrial chemicals, food, and personal care products. These compounds are often produced through palm refining, but recent work has demonstrated that MCFAs can also be produced through the fermentation of complex organic substrates, including organic waste streams. While “chain elongation” offers a renewable platform for producing MCFAs, there are several limitations that need to be addressed before full-scale implementation becomes widespread. Here, we review the history of work on MCFA production by both pure and mixed cultures of fermenting organisms, and the unique metabolic features that lead to MCFA production. We also offer approaches to address the remaining challenges and increase MCFA production from renewable feedstocks.

scholarly journals Spontaneous driving forces give rise to protein-RNA condensates with coexisting phases and complex material properties

2018 ◽  
Author(s):  
Steven Boeynaems ◽  
Alex S Holehouse ◽  
Venera Weinhardt ◽  
Denes Kovacs ◽  
Joris Van Lindt ◽  
...  
Keyword(s):  
Material Properties ◽  
Driving Forces ◽  
Coarse Grained ◽  
Biologically Relevant ◽  
Rna Molecules ◽  
Heterotypic Interactions ◽  
Collective Interactions

Collective phase transitions, including phase separation and gelation of multivalent protein and RNA molecules appears to underlie the biogenesis of biomolecular condensates such as membraneless organelles. In vivo, these condensates encompass hundreds of distinct types of molecules that are often organized into multi-layered structures supporting the differential partitioning of molecules into distinct regions with distinct material properties. The interplay between driven (active) versus spontaneous (passive) processes that are required for enabling the formation of condensates with coexisting layers of distinct material properties remains unclear. Here, we investigate the role of spontaneous driving forces as determinants of protein-RNA condensates with complex morphologies and distinct material properties. Through the use of systematic in vitro experiments and simulations based on coarse-grained models we find that that the collective interactions among the simplest, biologically relevant proteins and archetypal RNA molecules are sufficient for driving the spontaneous emergence of multi-layered condensates with distinct material properties. Our results demonstrate that key properties of protein-RNA condensates such as their overall morphologies, internal dynamics, and the selective partitioning of substrates are governed specific amino acid chemistries as well as RNA sequence and secondary structure. Our findings yield a clear set of heuristics regarding homo- and heterotypic interactions that are likely to be relevant for understanding the interplay between active and passive processes that control the formation of functional biomolecular condensates.

scholarly journals Identification of Strategic Molecules for Future Circular Supply Chains Using Large Reaction Networks

2019 ◽  
Author(s):  
Jana Weber ◽  
Pietro Lio’ ◽  
Alexei Lapkin
Keyword(s):  
Supply Chains ◽  
Chemical Reactions ◽  
Search Algorithm ◽  
Reaction Pathways ◽  
Reaction Networks ◽  
Waste Streams ◽  
Renewable Feedstocks ◽  
Generic Problem ◽  
Synthesis Routes ◽  
Isolation Forest

Networks of chemical reactions represent relationships between molecules within chemical supply chains and promise to enhance planning of multi-step synthesis routes from bio-renewable feedstocks. This study aims to identify <i>strategic molecules</i>in chemical reaction networks that may potentially play a significant role within the future circular economy. We mine a commercially available database in order to assemble a network of chemical reactions. We describe molecules within the network by a portfolio of graph theoretical features, and identify strategic molecules with an isolation forest search algorithm. In this work we have identified a list of potential strategic molecules and indicated possibilities for reaction planning using these. This is exemplified by a potential supply chain of functional molecules from bio-waste streams that could be used as feedstocks without being converted to syngas. This work extends the methodology of analysis of reaction networks to the generic problem of development of new reaction pathways based on novel feedstocks.

Material Properties of Discarded Textiles for Manufacturing Feedstocks

2021 ◽  
Author(s):  
Asad Bashir ◽  
Abigail R. Clarke-Sather ◽  
Tyler M. Poggogiale ◽  
Christopher L. Meehan
Keyword(s):  
Tensile Strength ◽  
Material Properties ◽  
Waste Streams ◽  
Fast Fashion ◽  
Control Applications ◽  
Significant Percentage ◽  
Textile Materials ◽  
Wear And Tear ◽  
Consumption Practices ◽  
Proportional Rate

Abstract Presently, many textiles are discarded, in a condition that would allow a significant percentage of them to be able to be completely reused or recycled. Recent consumption practices embodied by “fast fashion”, fast purchasing, and fast disposal of out of style clothing has increased the volume of discarded clothing, as the repurposing and/or recycling of discarded textile materials has not increased at a proportional rate. Consequently, discarded clothing may have nearly no wear and tear or extensive use before consumers choose to dispose of these textiles. Increasing the recovery of textiles from municipal solid waste streams involves understanding the material properties that discarded textiles possess. Measuring the material properties available from discarded textiles will allow for understanding whether these textiles can be reused. At the same time as disposal of textiles has increased, geotextile purchase and use has been increasing rapidly. In the current study, tensile strength (break force) and permittivity of discarded clothing samples made of cotton, polyester, and cotton-polyester blends were measured and compared with material properties that are commonly specified for geotextile applications. Average break force values measured for discarded cotton and polyester and average permittivity values measured for 50%/50% cotton-polyester blends and polyester are higher than what is commonly recommended for common geotextile applications. Polyester materials showed promise for drainage and erosion control applications that would be commonly serviced by geotextiles, as polyester samples yielded average break force and permittivity values are above typically recommended geotextile minimum values for these applications.

scholarly journals Identification of Strategic Molecules for Future Circular Supply Chains Using Large Reaction Networks

2019 ◽  
Author(s):  
Jana Weber ◽  
Pietro Lio’ ◽  
Alexei Lapkin
Keyword(s):  
Supply Chains ◽  
Chemical Reactions ◽  
Search Algorithm ◽  
Reaction Pathways ◽  
Reaction Networks ◽  
Waste Streams ◽  
Renewable Feedstocks ◽  
Generic Problem ◽  
Synthesis Routes ◽  
Isolation Forest

Networks of chemical reactions represent relationships between molecules within chemical supply chains and promise to enhance planning of multi-step synthesis routes from bio-renewable feedstocks. This study aims to identify <i>strategic molecules</i>in chemical reaction networks that may potentially play a significant role within the future circular economy. We mine a commercially available database in order to assemble a network of chemical reactions. We describe molecules within the network by a portfolio of graph theoretical features, and identify strategic molecules with an isolation forest search algorithm. In this work we have identified a list of potential strategic molecules and indicated possibilities for reaction planning using these. This is exemplified by a potential supply chain of functional molecules from bio-waste streams that could be used as feedstocks without being converted to syngas. This work extends the methodology of analysis of reaction networks to the generic problem of development of new reaction pathways based on novel feedstocks.

scholarly journals Spontaneous driving forces give rise to protein−RNA condensates with coexisting phases and complex material properties

2019 ◽  
Vol 116 (16) ◽  
pp. 7889-7898 ◽  
Author(s):  
Steven Boeynaems ◽  
Alex S. Holehouse ◽  
Venera Weinhardt ◽  
Denes Kovacs ◽  
Joris Van Lindt ◽  
...  
Keyword(s):  
Material Properties ◽  
Driving Forces ◽  
Coarse Grained ◽  
Multilayered Structures ◽  
Biologically Relevant ◽  
Rna Molecules ◽  
Coexisting Phases ◽  
Heterotypic Interactions ◽  
Collective Interactions

Phase separation of multivalent protein and RNA molecules underlies the biogenesis of biomolecular condensates such as membraneless organelles. In vivo, these condensates encompass hundreds of distinct types of molecules that typically organize into multilayered structures supporting the differential partitioning of molecules into distinct regions with distinct material properties. The interplay between driven (active) versus spontaneous (passive) processes that are required for enabling the formation of condensates with coexisting layers of distinct material properties remains unclear. Here, we deploy systematic experiments and simulations based on coarse-grained models to show that the collective interactions among the simplest, biologically relevant proteins and archetypal RNA molecules are sufficient for driving the spontaneous emergence of multilayered condensates with distinct material properties. These studies yield a set of rules regarding homotypic and heterotypic interactions that are likely to be relevant for understanding the interplay between active and passive processes that control the formation of functional biomolecular condensates.

Grain boundary segregation in metals

1992 ◽  
Vol 50 (2) ◽  
pp. 1204-1205
Author(s):  
C.L. Briant
Keyword(s):  
Fracture Surface ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Material Properties ◽  
Electron Spectroscopy ◽  
High Vacuum ◽  
Boundary Segregation ◽  
Grain Boundary Segregation ◽  
Local Concentration ◽  
The One

Grain boundary segregation is the process by which solute elements in a material diffuse to the grain boundaries, become trapped there, and increase their local concentration at the boundary over that in the bulk. As a result of this process this local concentration of the segregant at the grain boundary can be many orders of magnitude greater than the bulk concentration of the segregant. The importance of this problem lies in the fact that grain boundary segregation can affect many material properties such as fracture, corrosion, and grain growth.One of the best ways to study grain boundary segregation is with Auger electron spectroscopy. This spectroscopy is an extremely surface sensitive technique. When it is used to study grain boundary segregation the sample must first be fractured intergranularly in the high vacuum spectrometer. This fracture surface is then the one that is analyzed. The development of scanning Auger spectrometers have allowed researchers to first image the fracture surface that is created and then to perform analyses on individual grain boundaries.

Investigation of thin sections of biological standards by EDX, EELS, and Auger electron spectroscopy

1990 ◽  
Vol 48 (2) ◽  
pp. 184-185
Author(s):  
S. Lehner ◽  
H.E. Bauer ◽  
R. Wurster ◽  
H. Seiler
Keyword(s):  
Processing System ◽  
Beam Current ◽  
Beam Diameter ◽  
Thin Sections ◽  
Biologically Relevant ◽  
Energy Filtering ◽  
Low Viscosity ◽  
Carbon Foils ◽  
Electron Microscopical ◽  
Exchange Membrane

In order to compare different microanalytical techniques commercially available cation exchange membrane SC-1 (Stantech Inc, Palo Alto), was loaded with biologically relevant elements as Na, Mg, K, and Ca, respectively, each to its highest possible concentration, given by the number concentration of exchangeable binding sites (4 % wt. for Ca). Washing in distilled water, dehydration through a graded series of ethanol, infiltration and embedding in Spurr’s low viscosity epoxy resin was followed by thin sectioning. The thin sections (thickness of about 50 nm) were prepared on carbon foils and mounted on electron microscopical finder grids.The samples were analyzed with electron microprobe JXA 50A with transmitted electron device, EDX system TN 5400, and on line operating image processing system SEM-IPS, energy filtering electron microscope CEM 902 with EELS/ESI and Auger spectrometer 545 Perkin Elmer.With EDX, a beam current of some 10-10 A and a beam diameter of about 10 nm, a minimum-detectable mass of 10-20 g Ca seems within reach.

Quantification of cell-surface expressed antigenic sites with 5-nm gold markers: Getting close to biologically relevant data

1989 ◽  
Vol 47 ◽  
pp. 1050-1051
Author(s):  
Etienne de Harven ◽  
Hilary Christensen ◽  
Richard Leung ◽  
Cameron Ackerley
Keyword(s):  
Cell Surface ◽  
Human Peripheral Blood ◽  
Contour Length ◽  
Thin Sections ◽  
Gold Particles ◽  
Biologically Relevant ◽  
Transmission Electron ◽  
Entire Cell ◽  
Electron Imaging ◽  
Cell Contour

The T-derived subset of human peripheral blood normal lymphocytes has been selected as a model system to study the usefulness of 5 nm gold markers for quantification of single epitopes expressed on cell surfaces. The chosen epitopes are parts of the CD3 and CD5 molecules and can be specifically identified by hybridoma produced monoclonal antibodies (MoAbs; LEU-4 and LEU-1; Becton-Dick- inson, Mountain view, CA) . An indirect immunolabeling procedure, with goat anti-murine IgG adsorbed on the surface of 5 nm colloidal gold particles (GAM-G5, Janssen Pharmaceutica, Beerse, Belgium) has been used. Backscattered Electron Imaging (BEI) in a field emission scanning electronmicroscope (SEM) and transmission electron microscopy of thin sections of lymphocytes labeled before plastic embedding, were both used to identify and quantitate gold labeled cell surface sites, Estimating that the thickness of “silver” sections is approximately 60 nm and counting the number of gold particles on the entire cell perimeter, we calculated that, for LEU-4, the number of markers per um2 of cell surface is in the 140-160 range (Fig.l). Cell contour length measurements indicated that the surface of one lymphocyte is approximately 130-160 um2 that of a smooth sphere of identical diameter, reflecting the role of microvilli in expanding the surface area. The total number of gold labeled sites on the surface of one lymphocyte averages, therefore between 20,000 and 24,000 per cell.

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