Het boek Bodemraad is ontstaan vanuit een vraagstuk uit het agrarische werkveld. Er is een bedrijfsbezoek geweest bij de Gouden Boaiem te Smallebrugge. Het vraagstuk waarvoor een oplossing gezocht moet worden is als volgt: ‘Hoe kan biodiversiteit ingezet worden voor de gezondheid van het vee?’ De bodemraad is een boekje om inspiratie op te doen. Het geeft geen kant en klare oplossingen, maar geeft inspiratie voor veehouders om een nieuwe denkrichting in te slaan. Er worden verschillende problemen besproken, er wordt een samenhang tussen problemen besproken en daarnaast worden bekende en minder bekende oplossingen gegeven. Deze oplossingen kan de veehouder zelf verder uitwerken en toepassen waar nodig.
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The transition to a biobased economy necessitates utilizing renewable resources as a sustainable alternative to traditional fossil fuels. Bioconversion is a way to produce many green chemicals from renewables, e.g., biopolymers like PHAs. However, fermentation and bioconversion processes mostly rely on expensive, and highly refined pure substrates. The utilization of crude fractions from biorefineries, especially herbaceous lignocellulosic feedstocks, could significantly reduce costs. This presentation shows the microbial production of PHA from such a crude stream by a wild-type thermophilic bacterium Schlegelella thermodepolymerans [1]. Specifically, it uses crude xylose-rich fractions derived from a newly developed biorefinery process for grassy biomasses (the ALACEN process). This new stepwise mild flow-through biorefinery approach for grassy lignocellulosic biomass allows the production of various fractions: a fraction containing esterified aromatics, a monomeric xylose-rich stream, a glucose fraction, and a native-like lignin residue [2]. The crude xylose-rich fraction was free of fermentation-inhibiting compounds meaning that the bacterium S.thermodepolymerans could effectively use it for the production of one type of PHA, polyhydroxybutyrate. Almost 90% of the xylose in the refined wheat straw fraction was metabolized with simultaneous production of PHA, matching 90% of the PHA production per gram of sugars, comparable to PHA yields from commercially available xylose. In addition to xylose, S. thermodepolymerans converted oligosaccharides with a xylose backbone (xylans) into fermentable xylose, and subsequently utilized the xylose as a source for PHA production. Since the xylose-rich hydrolysates from the ALACEN process also contain some oligomeric xylose and minor hemicellulose-derived sugars, optimal valorization of the C5-fractions derived from the refinery process can be obtained using S. thermodepolymerans. This opens the way for further exploration of PHA production from C5-fractions out of a variety of herbaceous lignocellulosic biomasses using the ALACEN process combined with S. thermodepolymerans. Overall, the innovative utilization of renewable resources in fermentation technology, as shown herein, makes a solid contribution to the transition to a biobased economy.[1] W. Zhou, D.I. Colpa, H. Permentier, R.A. Offringa, L. Rohrbach, G.J.W. Euverink, J. Krooneman. Insight into polyhydroxyalkanoate (PHA) production from xylose and extracellular PHA degradation by a thermophilic Schlegelella thermodepolymerans. Resources, Conservation and Recycling 194 (2023) 107006, ISSN 0921-3449, https://doi.org/10.1016/j.resconrec.2023.107006. [2] S. Bertran-Llorens, W.Zhou. M.A.Palazzo, D.I.Colpa, G.J.W.Euverink, J.Krooneman, P.J.Deuss. ALACEN: a holistic herbaceous biomass fractionation process attaining a xylose-rich stream for direct microbial conversion to bioplastics. Submitted 2023.
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Several 2-nitroalkyl polysaccharide ethers (from pullulan (1), guar (2), agarose (3), inulin (4), cellulose (5), Na-α-polyglucuronate (6) and hydroxyethyl cellulose (7)) were synthesized by reaction with 2-nitro-1-alkenes (2-nitro-1-propene and 2-nitro-1-butene) formed in situ from 2-nitroalkyl acetates. Moderate to high efficiencies are obtained in concentrated aqueous solution/suspension for addition to 1-4 and 7. Analysis of this new class of polysaccharide derivatives with the aid of labeled 2-nitropropyl-2-13C pullulan revealed that the nitrogroup is a mixture of the nitroalkane and nitronic acid tautomers. Grafting of nitroalkenes is observed and, to a lesser extent, additional reactions of the nitro group (formation of carbonyl, oxime and allyl groups) take place. Reduction of 2-nitroalkyl polysaccharide ethers with Na2S2O4or Na2S2O4/NaBH4leads to complex polysaccharide ethers. The products obtained are most likely mixtures of starting material, nitroso compounds, hydroxylamines, hydroxypropyl ethers and sulfamates.
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