Understanding the flow behavior around marine biofilms.

platforms capable of mimicking the hydrodynamic conditions prevailing in natural aquatic environments have been previously validated and used to predict the fouling behavior on different surfaces. Computational Fluid Dynamics (CFD) has been used to predict the shear forces occurring in these platforms. In general, these predictions are made for the initial stages of biofilm formation, where the amount of biofilm does not affect the flow behavior, enabling the estimation of the shear forces that initial adhering organisms have to withstand.

Physico-Chemical Properties and Principal Component Analysis of Biobased Thermosets Developed with Different Batches of Industrial Humins.

Humins have already shown their potential as thermosetting resins to produce crosslinked networks and composites, with a large variety of properties depending on the used macromolecular approach. Our group has shown that a very interesting class of materials with tunable flexibility can be made by humins co-polymerization with glycerol diglycidyl ether (GDE). To create a clearer picture on structure-reactivity-properties-application interdependent relationship, a principal component analysis (PCA) was applied on several humins batches.

Fire Propagation Behavior of Some Biobased Furanic Compounds with a Focus on the Polymer PEF.

Avantium is in the process of building a flagship plant for the production of furandicarboxylic acid (FDCA) and the derived polyester polyethylene furanoate (PEF) using their YXY process. Because of the status of this development of monomer production, next to storage and shipping, polymer production, application development, and polymer recycling, the understanding of the safety aspects of the YXY process is key for a successful deployment of the technology. In this paper, the focus is on fire propagation-related issues for both monomeric furanic compounds and for the polymer PEF and results are compared with relevant reference materials.

Furanic Humins from Biorefinery as Biobased Binder for Bitumen.

To decrease the environmental impact of bitumen, more sustainable binders should be proposed. This study emphasizes how industrial humins co-produced during the biorefining of carbohydrates can be employed as a macromolecular binder for bitumen. Humins are heterogeneous polyfuranic compounds, and they were mixed at 50 wt% with bitumen.

The Road to Bring FDCA and PEF to the Market.

Biobased polymers and materials are desperately needed to replace fossil-based materials in the world's transition to a more sustainable lifestyle. In this article, Avantium describes the path from invention towards commercialization of their YXY plants-to-plastics Technology, which catalytically converts plant-based sugars into FDCA-the chemical building block for PEF (polyethylene furanoate). PEF is a plant-based, highly recyclable plastic, with superior performance properties compared to today's widely used petroleum-based packaging materials.

Unveiling the Antifouling Performance of Different Marine Surfaces and Their Effect on the Development and Structure of Cyanobacterial Biofilms.

Since biofilm formation by microfoulers significantly contributes to the fouling process, it is important to evaluate the performance of marine surfaces to prevent biofilm formation, as well as understand their interactions with microfoulers and how these affect biofilm development and structure. In this study, the long-term performance of five surface materials-glass, perspex, polystyrene, epoxy-coated glass, and a silicone hydrogel coating-in inhibiting biofilm formation by cyanobacteria was evaluated. For this purpose, cyanobacterial biofilms were developed under controlled hydrodynamic conditions typically found in marine environments, and the biofilm cell number, wet weight, chlorophyll content, and biofilm thickness and structure were assessed after 49 days.

Kinetics and Chemorheological Analysis of Cross-Linking Reactions in Humins.

Humins is a biomass-derived material, co-product of the acid-catalyzed conversion of cellulose and hemicellulose to platform chemicals. This work presents a thorough study concerning the crosslinking kinetics of humins by chemorheological analysis and model-free kinetics under isothermal and non-isothermal curing. Humins can auto-crosslink under the effect of temperature, and the reaction can be fastener when adding an acidic initiator.

Biofilm formation behaviour of marine filamentous cyanobacterial strains in controlled hydrodynamic conditions.

Marine biofouling has severe economic impacts and cyanobacteria play a significant role as early surface colonizers. Despite this fact, cyanobacterial biofilm formation studies in controlled hydrodynamic conditions are scarce. In this work, computational fluid dynamics was used to determine the shear rate field on coupons that were placed inside the wells of agitated 12-well microtiter plates.

Bacterial Density and Biofilm Structure Determined by Optical Coherence Tomography.

Optical-coherence-tomography (OCT) is a non-destructive tool for biofilm imaging, not requiring staining, and used to measure biofilm thickness and putative comparison of biofilm structure based on signal intensity distributions in OCT-images. Quantitative comparison of biofilm signal intensities in OCT-images, is difficult due to the auto-scaling applied in OCT-instruments to ensure optimal quality of individual images. Here, we developed a method to eliminate the influence of auto-scaling in order to allow quantitative comparison of biofilm densities in different images.

Role of Viscoelasticity in Bacterial Killing by Antimicrobials in Differently Grown Biofilms.

colonizes the sputum of most adult cystic fibrosis patients, forming difficult-to-eradicate biofilms in which bacteria are protected in their self-produced extracellular polymeric substance (EPS) matrices. EPS provide biofilms with viscoelastic properties, causing time-dependent relaxation after stress-induced deformation, according to multiple characteristic time constants. These time constants reflect different biofilm (matrix) components.

Auto-Crosslinked Rigid Foams Derived from Biorefinery Byproducts.

A new macroporous foam-like material is presented based on autocross-linking humins, an industrial biorefinery byproduct. Humins foams are obtained by a simple heating process, without any pretreatment and with high control of morphology, porosity, and carbon content. Untreated humins have been characterized by GC, ultra-performance liquid chromatography (UPLC), elemental analysis, and FTIR, whereas the mechanism of foaming was elucidated by a combination of thermal and rheological analyses.

Structural changes in S. epidermidis biofilms after transmission between stainless steel surfaces.

Transmission is a main route for bacterial contamination, involving bacterial detachment from a donor and adhesion to receiver surfaces. This work aimed to compare transmission of an extracellular polymeric substance (EPS) producing and a non-EPS producing Staphylococcus epidermidis strain from biofilms on stainless steel. After transmission, donor surfaces remained fully covered with biofilm, indicating transmission through cohesive failure in the biofilm.

Preparation and crystallization behavior of poly(ethylene 2,5-furandicarboxylate)/cellulose composites by twin screw extrusion.

Poly(ethylene 2,5-furandicarboxylate) (PEF), an emerging biobased polyester, was compounded with cellulose via twin-screw extrusion. Different extrusion parameters such as mixing time, screw speed and temperature were employed. Composite thin films containing 1, 2 and 4% cellulose w/w were prepared and compared with neat PEF films.

Reactivity studies in water on the acid-catalysed dehydration of psicose compared to other ketohexoses into 5-hydroxymethylfurfural.

The conversion of the four possible ketohexoses (fructose, tagatose, sorbose and psicose) into 5-hydroxymethylfurfural (HMF) was explored in water using sulphuric acid as the catalyst (33 mM HSO, 120 °C). Significant differences in reactivity were observed and tagatose (48% conversion after 75 min) and psicose (35% conversion after 75 min) were clearly more reactive than fructose and sorbose (around 20% conversion after 75 min). The selectivity to HMF was found to be higher for fructose and psicose than for tagatose and sorbose.

Selectivity Control in the Tandem Aromatization of Bio-Based Furanics Catalyzed by Solid Acids and Palladium.

Bio-based furanics can be aromatized efficiently by sequential Diels-Alder (DA) addition and hydrogenation steps followed by tandem catalytic aromatization. With a combination of zeolite H-Y and Pd/C, the hydrogenated DA adduct of 2-methylfuran and maleic anhydride can thus be aromatized in the liquid phase and, to a certain extent, decarboxylated to give high yields of the aromatic products 3-methylphthalic anhydride and o- and m-toluic acid. Here, it is shown that a variation in the acidity and textural properties of the solid acid as well as bifunctionality offers a handle on selectivity toward aromatic products.

A Comparative Study on the Reactivity of Various Ketohexoses to Furanics in Methanol.

The acid-catalysed dehydration of the four 2-ketohexoses (fructose, sorbose, tagatose and psicose) to furanics was studied in methanol (65 g L(-1) substrate concentration, 17 and 34 mm sulfuric acid, 100 °C) with Avantium high-throughput technology. Significant differences in the reactivities of the hexoses and yields of 5-hydroxymethylfurfural (HMF) and its methyl ether (MMF) were observed. Psicose and tagatose were the most reactive, and psicose also afforded the highest combined yield of MMF and HMF of approximately 55 % at 96 % sugar conversion.

A Facile Solid-Phase Route to Renewable Aromatic Chemicals from Biobased Furanics.

Renewable aromatics can be conveniently synthesized from furanics by introducing an intermediate hydrogenation step in the Diels-Alder (DA) aromatization route, to effectively block retro-DA activity. Aromatization of the hydrogenated DA adducts requires tandem catalysis, using a metal-based dehydrogenation catalyst and solid acid dehydration catalyst in toluene. Herein it is demonstrated that the hydrogenated DA adducts can instead be conveniently converted into renewable aromatics with up to 80% selectivity in a solid-phase reaction with shorter reaction times using only an acidic zeolite, that is, without solvent or dehydrogenation catalyst.

Substituted Phthalic Anhydrides from Biobased Furanics: A New Approach to Renewable Aromatics.

A novel route for the production of renewable aromatic chemicals, particularly substituted phthalic acid anhydrides, is presented. The classical two-step approach to furanics-derived aromatics via Diels-Alder (DA) aromatization has been modified into a three-step procedure to address the general issue of the reversible nature of the intermediate DA addition step. The new sequence involves DA addition, followed by a mild hydrogenation step to obtain a stable oxanorbornane intermediate in high yield and purity.

Selective electrocatalytic oxidation of sorbitol to fructose and sorbose.

A new electrocatalytic method for the selective electrochemical oxidation of sorbitol to fructose and sorbose is demonstrated by using a platinum electrode promoted by p-block metal atoms. By the studying a range of C4, C5 and C6 polyols, it is found that the promoter interferes with the stereochemistry of the polyol and thereby modifies its reactivity.

Early-stage comparative sustainability assessment of new bio-based processes.

Our increasing demand for materials and energy has put critical roadblocks on our path towards a sustainable society. To remove these roadblocks, it is important to engage in smart research and development (R&D). We present an early-stage sustainability assessment framework that is used to analyze eight new bio-based process alternatives developed within the CatchBio research consortium in the Netherlands.

Dehydration of different ketoses and aldoses to 5-hydroxymethylfurfural.

5-Hydroxymethylfurfural (HMF) is considered an important building block for future bio-based chemicals. Here, we present an experimental study using different ketoses (fructose, sorbose, tagatose) and aldoses (glucose, mannose, galactose) under aqueous acidic conditions (65 g L(-1) substrate, 100-160 °C, 33-300 mM H2 SO4 ) to gain insights into reaction pathways for hexose dehydration to HMF. Both reaction rates and HMF selectivities were significantly higher for ketoses than for aldoses, which is in line with literature.

Electrocatalytic hydrogenation of 5-hydroxymethylfurfural in the absence and presence of glucose.

Electrocatalytic hydrogenation of 5-hydroxymethylfurfural (HMF) to 2,5-dihydroxymethylfuran (DHMF) or other species, such as 2,5-dimethylfuran, on solid metal electrodes in neutral media is addressed, both in the absence and in the presence of glucose. The reaction is studied by combining voltammetry with on-line product analysis by using HPLC, which provides both qualitative and quantitative information about the reaction products as a function of electrode potential. Three groups of catalysts show different selectivity towards: (1) DHMF (Fe, Ni, Ag, Zn, Cd, and In), (2) DHMF and other products (Pd, Al, Bi, and Pb), depending on the applied potential, and (3) other products (Co, Au, Cu, Sn, and Sb) through HMF hydrogenolysis.