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- Aldaeus, Fredrik, et al.
(författare)
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Characterization of pulp with high enzymatic hydrolyzability
- 2014
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Ingår i: 13th European Workshop on Lignocellulosics and Pulp (EWLP 2014) book of abstracts.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Conversion of biomass to biofuels is currently an area that attracts large interest, and lignocellulosic biomass offers the abundance and environmental attributes that can potentially support large-scale biofuel production as an alternative to petroleum-based transportation fuel.In a recent project, Innventia has developed wood based pulps optimized for conversion to biofuels. These novel pulps were produced to target a high level of enzymatic hydrolyzability. To assess the hydrolyzability of these pulps, a laboratory protocol has been established usingan enzyme mixture containing Celluclast 1.5L and Novozyme 188 with an activity of 10 FPU/g pulp (Andersen 2007). Results obtained using this protocol are assumed to be relevant for industrial conditions. In addition to assessment of the produced pulps, the results havebeen compared to commercial cellulose substrates and pulps of a variety of grades.Furthermore, supramolecular properties – specific surface area and average pore size – were determined by an in-house method utilizing solid state nuclear magnetic resonance (Larsson et al. 2013). Kappa numbers, limiting viscosities, ISO-brightness and carbohydrate compositions were determined using standard methods. Molecular mass distributions of cellulose tricarbanilates were determined by size exclusion chromatography with tetrahydrofuran mobile phase (Drechsler et al. 2000).The presentation will discuss the influence of chemical, macromolecular and supramolecular properties of commercial and novel pulp grades on the enzymatic hydrolyzability. Theprotocol used to assess of enzymatic hydrolyzability will be proposed as a benchmark test.
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| 2. |
- Aldaeus, Fredrik, et al.
(författare)
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The supramolecular structure of cellulose-rich wood and wheat straw pulps can be a determinative factor for enzymatic hydrolysability
- 2016
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Ingår i: The 7th Workshop on cellulose, regenerated cellulose and cellulose derivatives. ; , s. 39-39
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Conversion of biomass to biofuels and other products is a research area that is currently attracting a great amount of interest, particularly because such production may be envisaged as a key part of any bio-based economy. Lignocellulosic biomass is abundant and sustainable, and can therefore potentially support large-scale production of biofuel as an alternative to petroleum-based fuel.The enzymatic hydrolysability of three industrial pulps, five lab made pulps, and one microcrystalline cellulose powder was assessed using commercial cellulolytic enzymes. To gain insight into the factors that influence the hydrolysability, a thorough characterization of the samples was done, including their chemical properties (cellulose content, hemicellulose content, lignin content, and kappa number), their macromolecular properties (peak molar mass, number-average molar mass, weight-average molar mass, polydispersity, and limiting viscosity) and their supramolecular properties (fibre saturation point, specific surface area, average pore size, and crystallinity). The hydrolysability was assessed by determination of initial conversion rate and final conversion yield, with conversion yield defined as the amount of glucose in solution per unit of glucose in the substrate. Multivariate data analysis revealed that for the investigated samples the conversion of cellulose to glucose was mainly dependent on the supramolecular properties, such as specific surface area and average pore size. The molar mass distribution, the crystallinity, and the lignin content of the pulps had no significant effect on the hydrolysability of the investigated samples.In addition, experiments were carried out aiming at identifying suitable conditions for pre-treatment of wheat straw, for the purpose of making cellulose rich pulps with improved enzymatic reactivity. Two sets of conditions for pre-treatment of wheat straw were identified; a combination of low temperature alkaline washing and acid pre-hydrolysis, or high temperature acid pre-hydrolysis. Both bleached wheat straw pulps showed similar enzymatic reactivity. However, the enzymatic reactivity of both bleached wheat straw pulps was found to be significantly less than what has been achieved for wood pulps. A probable explanation for the low enzymatic reactivity of the bleached wheat straw pulp can be the small pore size, limiting the access for enzymes to the cellulose surfaces in the fibre wall interior.Text, figures and tables in an extended abstract (< 4 pages with title and references).
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| 4. |
- Larsson, Magnus, 1983-
(författare)
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National environmental evaluation systems : guiding towards sustainability?
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Dealing with environmental threats is one of the largest, if not the largest, challenge contemporary societies face. One way to better deal with this challenge would be to produce knowledge that can be used to improve environmental work and environmental policy and thus ultimately contribute to sustainable development. National environmental evaluations, which this thesis explores, could potentially fill this function because they are supposed to generate applicable and useful knowledge for improving environmental policy and practice for a sustainable transition. However, what different environmental actors view as useful knowledge varies, and needs to be empirically investigated. Against this background, the aim of this thesis is to investigate whether, and how, national environmental evaluation systems contribute to key actors’ environmental work and sustainable development. The thesis explores two national environmental evaluation systems in Sweden.Method: A mixed methods approach is applied that combines three methods. Firstly, a narrative synthesis is developed and applied to compile a list of sustainable development effects from national environmental evaluations. Secondly, a critical program theory is used to investigate the evaluation system’s underlying logic and to assess the likelihood of it achieving its intended effects. Thirdly, a directed content analysis is used to explore the usability and use of environmental evaluations and evaluation systems. The methods are applied to various documents, interviews with key actors, and observations at two environmental seminars.Results: The results show that, to contribute to sustainable development in the context of evaluation systems and network governance, environmental evaluations need to be of sufficient quality and meet different stakeholders’ knowledge needs. However, only some evaluations meet this demand. The main value of national environmental evaluations and evaluation systems is that they reinforce the national objectives, provide a recurrent report on achievement of objectives, and push actors to take responsibility to improve their environmental work.
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| 5. |
- Larsson, Per Tomas, et al.
(författare)
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Characterization of cellulose supramolecular structure using solid-state NMR
- 2014
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Ingår i: Analysdagarna book of abstracts.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Cellulose I isolated from wood in the form of cellulose-rich fibres, i.e. as a pulp, is a widely used raw material that holds a potential for further and more versatile use. Due to its abundance cellulose can be a benign replacement for many materials used in everydaycommodities.Isolated cellulose I is associated with a complex supramolecular structure (in the nanometresdimensional range), and in the case of cellulose-richfibres it is also associated with a complex fibre wall morphology (typical wood fibres are millimetres long and tenths of micrometres wide).The main advantage of using cellulose-rich fibres is an existence of a worldwide industry which has the processing equipment and the know-how necessary for efficient handling and processing of wood-based pulps.Utilization of cellulose I is dependent on the reactivity of the cellulose substrate, here the term reactivity is used in a broad sense. Enzymatic conversion of cellulose-rich fibres to sugars or the dissolution of cellulose for textile fibre manufacture is two examples where different aspects of the cellulosereactivity are important for efficient processing.Several methods for characterizing various aspects of cellulose are available. The degree of polymerization and the degree of cellulose crystallinity are two examples. In the case of cellulose-rich fibres its carbohydrate composition can be of importance. Traditionally lessattention has been paid to the supramolecular characteristics of cellulose although they are in a dimensional range that could exert an influence on the chemistry used.The present work deals with the characterization of the supramolecular properties of cellulose and cellulose-rich fibres and illustrates some examples where the supramolecular structure of the cellulose is a controlling factor for its reactivity. Most of the presented work is based on CP/MAS 13 C-NMR measurements. Using this technique it has been shown that robust measurements of cellulose nanostructures such aslateral fibril dimensions and lateral fibril aggregate dimensions can be obtained and how subsequently the specific surface area of the cellulose in a water-swollen state can be estimated. Moreover, by combining NMR resultswith measurements of the amount of water located inside a water-swollen fibre wall, estimates of the average fibre wall pore size can be obtained. Such results have beenrelated to data from enzymatic hydrolysis of cellulose-richfibres to illustrate the influence of supramolecular structure on enzymatic reactivity.
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| 6. |
- Nyström, Katarina, et al.
(författare)
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Specific T-cell responses for guiding treatment with convalescent plasma in severe COVID-19 and humoral immunodeficiency : a case report
- 2022
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Ingår i: BMC Infectious Diseases. - : BMC. - 1471-2334. ; 22:1
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Tidskriftsartikel (refereegranskat)abstract
- Background The immune response to SARS-CoV-2 virus, the cause of COVID-19, is complex. Antibody mediated responses are important for viral clearance but may also drive hyperinflammation in severe COVID-19. We present a case of an individual with a genetic inability to produce antibodies and severe COVID-19, receiving no other specific anti-viral treatment than convalescent COVID-19 plasma, illustrating that hyperinflammation can occur in the absence of a humoral anti-viral response. In addition, the case illustrates that the assessment of SARS-CoV-2 T cell responses can facilitate clinical decision making in patients with COVID-19 and weak or absent humoral immune responses. Case presentation A male with X-linked agammaglobulinemia on regular immunoglobulin replacement therapy, hospitalized for 35 days due to severe COVID-19. Systemic inflammatory parameters were highly elevated. After treatment with convalescent COVID-19 plasma he became afebrile and the fatigue diminished. He was discharged on day 42 and nasopharyngeal SARS-CoV-2 PCR eventually was negative on day 49. Evidence of SARS-CoV-2 specific T cells prior to administration of plasma therapy suggested that antibodies were crucial for viral clearance. Regular assessment showed robust and persistent SARS-CoV-2 specific T-cell responses after recovery suggested that prophylactic administration of convalescent COVID-19 plasma was unnecessary. Conclusion Assessment of SARS-CoV-2T-cell responses can facilitate the clinical management of COVID-19 patients with humoral immunodeficiencies.
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| 9. |
- Sundelöf, Andreas, et al.
(författare)
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Fisk- och skaldjursbestånd i hav och sötvatten 2021 : Resursöversikt
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- I rapporten kan du ta del av bedömningen som görs av situationen för bestånd som regleras inom ramen för EU:s gemensamma fiskeripolitik (GFP). Bedömningarna baseras på det forskningssamarbete och den rådgivning som sker inom det Internationella Havsforskningsrådet (ICES). Sammantaget redovisas tillståndet för 107 bestånd av 48 fisk- och skaldjursarter.De bestånd som förvaltas nationellt baseras på de biologiska underlagen, och rådgivningen i huvudsak på den forskning och övervakning samt analys som bedrivs av Institutionen för akvatiska resurser vid Sveriges lantbruksuniversitet (SLU Aqua) samt yrkesfiskets rapportering.Rapporten är en beställning från Havs- och vattenmyndigheten (HaV) till Sveriges lantbruksuniversitet (SLU) och utgör ett viktigt kunskapsunderlag till myndighetens arbete. Den uppfyller de krav som finns inom EU:s gemensamma fiskeripolitik om att basera förvaltningen på bästa tillgängliga vetenskap. Denna rapport är också ett stöd till det arbete som beskrivs närmare i strategin för framtidens fiske och tillhörande handlingsplaner för vattenbruk, yrkes- och fritidsfiske som HaV och Jordbruksverket har tagit fram i dialog med fiskets och vattenbrukets intressenter.
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