Amylomaltases or D-enzyme (4-α-glucanotransferases; E.C. 2.4.1.25) are carbohydrate-active enzymes that catalyze the transfer of glucan units from one α-glucan to another in a disproportionation reaction. These enzymes are involved in starch metabolism in plants or maltose/glycogen metabolism in many microorganisms. The amylomaltase of the hyperthermophilic bacterium Thermus thermophilus HB8 was overproduced in Escherichia coli, partially purified and used to modify potato starch. The action of amylomaltase caused the disappearance of amylose and the broadening of the side-chain length distribution in amylopectin, which resulted in a product with both shorter and longer side chains than in the parent starch. Amylomaltase-treated potato starch showed thermoreversible gelation at concentrations of 3% (w/v) or more, thus making it comparable to gelatin. Because of its animal origin, gelatin is not accepted by several consumer groups. Therefore, the amylomaltase-treated potato starch might be a good plant-derived substitute for gelatin. ? 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Granular 2-nitropropyl potato starch was synthesized by reaction with 2-nitropropyl acetate in an aqueous suspension. Nitroalkylation occurs preferentially with the amylose fraction of potato starch, as was confirmed by leaching experiments and digestion of the modified starch with α-amylase. The 2-nitropropyl substituent is a mixture of the nitroalkane and nitronic acid tautomer. Some grafting occurs and to a lesser extent additional reactions (formation of carbonyls and oximes) of the nitro group take place. After catalytic hydrogenation of water soluble 2-nitropropyl starch only a small amount of the nitro functionality was reduced to the corresponding amine. Reduction of granular 2-nitropropyl starch with sodium dithionite did not go to completion and led to a complex mixture of starting material, several intermediates and side products (for example sulfamates). © 2001 Elsevier Science Ltd.
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Granular starch was cross-linked with 1,3-di-O-acetyl-2-nitro-1,3-propanediol (1), 1,3-di-O-pivaloyl-2-nitro-1,3-propanediol (2), 2-nitro-3-O-pivaloyl-1-propene-3-ol (3), 1,3-di-O-acetyl-aci-2-nitro-1,3-propanediol (4), 1,3-di-O-pivaloyl-aci-2-nitro-1,3-propanediol (5) and 1,6-di-O-acetyl-2,5-dinitro-1,6-hexanediol (6). The bifunctional precursors for the nitro-alkenes 1, 2, 3, and 4 were readily synthesized in high yields from nitromethane, paraformaldehyde and acetic anhydride (1, 3) or pivaloyl chloride (2, 4), respectively. The reaction rate for the cross-linking was very high, and for 1 and 3, the reaction reached completion within 1 h (at room temperature). The swelling capacities of the products obtained when starch was cross-linked with precursors for the nitroalkenes 1-4 and 6 were lower in comparison to epichlorohydrin cross-linked starch. These results indicate a high reaction efficiency at low degrees of substitution. Cross-linked 2-nitroalkyl starch ethers were synthesized in a one-pot synthesis by addition of 1 or 3 and 2-nitroalkyl acetates to granular suspensions of starch. Copyright (C) 1998 Elsevier Science Ltd.
Nederland heeft hoge ambities rond de ontwikkeling van duurzame coatings die o.a. ingezet worden in de agrosector ter bescherming van gewassen en om opbrengsten te maximaliseren. De toepassing van de huidige op olie gebaseerde coatings wordt in de komende jaren in de EU uitgefaseerd. Niet alleen omdat ze op olie zijn gebaseerd maar ook omdat ze bij afbraak kunnen leiden tot vervuilende microplastics. Vanuit de markt is er daarom een grote behoefte aan alternatieven. Een alternatief zijn biobased coatings. De nieuwe biobased grondstof Kaumera kan een bijdrage leveren aan de ontwikkeling van deze biobased coatings. Op de afvalwaterzuiveringsinstallatie Zutphen (in beheer bij Waterschap Rijn en IJssel) wordt sinds 2020 de Kaumera gewonnen uit aeroob korrelslib. De toepassing van Kaumera beperkt zich op dit moment tot toepassing als biostimulant in de land- en tuinbouw. Kaumera heeft echter ook eigenschappen die kansen bieden voor toepassingen in biobased coatings in de agro-sector. In 2023 is door Avans samen met het waterschap een studentenproject uitgevoerd waarin gekeken is naar de chemische modificatie van Kaumera door middel van een carboxymethylering. Dit resulteerde in een uniek materiaal: carboxymethyl-Kaumera (CMK). In dit Kaumeleon project gaat het consortium bestaande uit het Waterschap Rijn en IJsel, Dynaplak Adhesive and Starches B.V. en Avans Hogeschool kijken naar het verder ontwikkelen van dit CMK richting specifieke toepassingen in coatings. De vragen die centraal staat zijn: hoe kan carboxymethylering van Kaumera worden geoptimaliseerd, welke eigenschappen levert dit op, en wordt het product daarmee geschikt voor toepassing als biobased coating? Met dit project beoogt het consortium op de middellange termijn een bijdrage te leveren aan het vervangen van primaire grondstoffen door duurzame biobased alternatieven uit reststromen, en zo aan het verduurzamen van de chemische industrie.
The building industry is a major target for resource-efficiency developments, which are crucial in European Union’s roadmaps. Using renewable materials impacts the sustainability of buildings and is set as urgent target in current architectural practice. The building industry needs renewable materials positively impacting the CO2 footprint without drawbacks. The use of wood and timber as renewable construction materials has potentials, but also drawbacks because trees need long time to grow; producing timber generates considerable waste; and the process from trees to applications in buildings requires transportation and CO2 emission. This research generates new scientific knowledge and a feasibility study for a new wood-like bio-material - made of cellulose and lignin from (local) residual biomass via i.e. 3D printing - suitable for applications in the building industry. It contributes to a sustainable built environment as it transforms waste from different sectors into a local resource to produce a low carbon-footprint bio-material for the construction sector. Through testing, the project will study the material properties of samples of raw and 3D printed material, correlating different material recipes that combine lignin and cellulose and different 3D printing production parameters. It will map the material properties with the requirements of the construction industry for different building products, indicating potentials and limits of the proposed bio-material. The project will produce new knowledge on the material properties, a preliminary production concept and an overview of potentials and limits for application in the built environment. The outcome will be used by industry to achieve a marketable new bio-material; as well as in further scientific academic research.
