Microencapsulation of cells is a promising approach to prevent rejection in the absence of immunosuppression. Clinical application, however, is hampered by insufficient insight in factors influencing biocompatibility of the capsules in humans. In the present study we exposed alginate-based capsules prepared of different types of alginate to human peritoneal fluid. Subsequently we studied the physicochemical changes of the capsule's surface by applying micro-Fourier Transform Infrared Spectroscopy. We did test alginate-beads and alginate-poly-L-lysine capsules prepared of different types of alginate. In all tested capsule formulations we found adsorption of components from human peritoneal fluid and clear physicochemical changes of the surface. These changes were alginate-dependent. The adsorption had no significant effects on the permselective properties of the capsule but we found a strong increase of TNFα production by human peripheral blood mononuclear cells when exposed to alginate-beads treated with human peritoneal fluid. This elevated responsiveness was not observed with alginate-PLL capsules. The results show that alginate-based capsule surfaces always undergo physicochemical changes of the surface when exposed to human peritoneal fluid. This adsorption may lead to enhancement of the inflammatory responses against the microcapsules. Our result implicate that biocompatibility measurements should not only been done with freshly prepared capsules but also with capsules that have been exposed to fluid from the implantation site in order to predict the in vivo responses. Copyright © 2011 Wiley Periodicals, Inc.
Global society is confronted with various challenges: climate change should be mitigated, and society should adapt to the impacts of climate change, resources will become scarcer and hence resources should be used more efficiently and recovered after use, the growing world population and its growing wealth create unprecedented emissions of pollutants, threatening public health, wildlife and biodiversity. This paper provides an overview of the challenges and risks for sewage systems, next to some opportunities and chances that these developments pose. Some of the challenges are emerging from climate change and resource scarcity, others come from the challenges emerging from stricter regulation of emissions. It also presents risks and threats from within the system, next to external influences which may affect the surroundings of the sewage systems. It finally reflects on barriers to respond to these challenges. http://dx.doi.org/10.13044/j.sdewes.d6.0231 LinkedIn: https://www.linkedin.com/in/sabineeijlander/ https://www.linkedin.com/in/karel-mulder-163aa96/
MULTIFILE
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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The research for alternatives to substitute cement in concrete increased in the last years to reduce the environmental impact. Geopolymers or alkali-activated materials are one of the options. The proposed project aims to obtain a wet cell based on a geopolymer with alginate and natural fibres. The wet cell will be a final prototype composed of panels for wet construction areas such as bathrooms and kitchens. There is a lack of biobased solutions for wet areas currently in the market. And the present project, together with companies of suppliers and users from the market, aims to provide a solution for a wet cell using biobased materials. The natural fibres added to the geopolymer will substitute a portion of sand and gravel, producing a lighter product than concrete. Also, the fibres increase the thermal and acoustic insulation. Natural fibres should be pretreated to increase the bond with other materials in the mixture. The chemical used in the alkali-activated materials is the same to pretreat the fibres. Also, alginates extracted from seaweeds can be used as binders, and alkali is used in the extraction process. One of the objectives is to develop the method and technique to produce geopolymer with alginates and pretreat the fibre simultaneously during the mixture. After defining the optimum mixture for the geopolymer, panels will be produced, and in the end, a wet cell will be constructed with the geopolymer panels.
