Utnyttelse av H2O2-drevet lytisk polysakkarid monooksygenase-aktivitet i cellulaseblandinger for forbedret bioprossesering av lignocelluloseholdig biomasse

Rapid action is critical to reduce anthropogenic CO2 emissions in order to reach climate targets. Fossil fuel use in high emission sectors like the energy and chemical industry should therefore be reduced and replaced by sustainable alternatives. Lignocellulosic biomass, like Norwegian spruce, has potential to replace commonly used feedstocks like corn and sugarcane in a biorefinery for production of biofuels and bio-based chemicals due to its high abundance, high proportion of polysaccharides, and limited competition for arable land. Lignocellulose is a highly recalcitrant feedstock that requires high severity pretreatment and enzyme loads to produce fermentable sugars. The inclusion of lytic polysaccharide monooxygenase (LPMO) to cellulase cocktails has previously been shown to enhance saccharification yields considerably. Recent findings that LPMO activity is driven by H2O2 opens the door to novel process setups to fully harness this potential. The aim of this thesis was to improve the conversion of lignocellulosic biomass by altering process conditions to maximize the impact of LPMOs in saccharification and fermentation processes. In Paper 1, recent developments within enzymatic processing of lignocellulosic biomass are summarized, and we show the interconnectedness between pretreatment and saccharification, and how this affects LPMOs in the cellulase cocktail. The implications of direct addition of H2O2 compared to in-situ generation is discussed in relation to choice of feedstock and process design. The results in Paper 2 demonstrate how negative impacts from residual lignin in the saccharification step can be alleviated by inclusion of the carbocation scavenger 2-naphthol in a steam explosion pretreatment. Lignin resulting from 2-naphthol-impregnated samples improved LPMO activity not only in the cellulase cocktail but also of the chitin-active LPMO CBP21 (SmAA10A), showing that more H2O2 could be generated in the presence of impregnated lignin. This paper also explores a potential combination of biochemical (i.e., enzymatic saccharification) and thermochemical (i.e., pyrolysis) conversion steps for a softwood-based biorefinery. Impregnation had no negative impacts on bio-oil produced by pyrolysis. In Paper 3, direct addition of H2O2 to separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) processes was used to boost LPMO activity in a commercial enzyme cocktail. Production of lactic acid by B. coagulans in an SSF setup was found to be competitive with the SHF process in this study contrary to previous findings. In particular, feeding H2O2 during SSF enabled oxidative cellulose depolymerization by LPMOs present in a cellulase cocktail under anaerobic conditions. Overall, the findings presented in this thesis illustrate how latent potential of LPMOs in commercial cellulase cocktails can be utilized to improve existing saccharification and fermentation processes. This is particularly relevant for bioprocessing of recalcitrant lignocellulosic feedstocks like the softwood Norway spruce.For å redusere menneskeskapte CO2-utslipp og for å nå klimamålene er det avgjørende å handle raskt. Bruk av fossilt brensel i høyutslippssektorer som energi- ogkjemisk industri bør derfor reduseres og erstattes av bærekraftige alternativer. Lignocelluloseholdig biomasse, som for eksempel norsk gran, kan potensielt erstatte vanlig brukte råvarer som mais og sukkerrør i et bioraffineri for produksjon av biodrivstoff og biobaserte kjemikalier på grunn av den finnes i store mengder, har høyt innhold polysakkarider og i liten grad konkurrerer om dyrkbar jord. Lignocellulose er et svært gjenstridig råmateriale som krever intens forbehandling og høy enzymbelastning for å produsere fermenterbare sukker. Å inkludere lytisk polysakkarid monooksygenaser (LPMOer) i cellulaseblandinger har tidligere vist seg å øke sukkerutbyttet betraktelig. Nye oppdagelser som viser at LPMO-aktivitet er drevet av H2O2 muliggjør nye prosessoppsett som kan utnytte dette potensialet fullt ut. Målet med denne oppgaven var å forbedre omdannelsen av lignocelluloseholdig biomasse ved å endre prosessforhold for å maksimere virkningen av LPMO i sukkerfrigjørings- og fermenteringsprosesser

Therapists’ experiences with providing guided internet-delivered cognitive behavioral therapy for patients with mild to moderate depression: a thematic analysis

Introduction: Guided internet-delivered therapy has shown promising results for patients with mild and moderate depressive disorder, but several challenges with the format have been reported. The aim of this qualitative study was to investigate therapists’ experiences providing guided internet-delivered cognitive behavioral therapy for patients with mild and moderate depression. Material and methods: Twelve therapists were interviewed, and the interviews were analyzed using reflexive thematic analysis. Results and conclusion: Three themes were created: (1) For the right person, at the right time. This theme is about therapists’ experiences appointing patients to the program. It is challenging to predict which patients will benefit from it, and it is not the right option for all patients. (2) It is not like chatting on Facebook. The second theme was about the experiences with demands on clinics, therapists and patients that must be considered. The internet-delivered treatment should not be viewed as a simple treatment option, and the value of having contact with the patients during treatment was emphasized. (3) It is like a railroad, but without the switches. This theme was about the experiences with how the treatment content was conveyed to the patients, how the therapists expressed concerns with the usability of the program and the reported need for more possibilities in tailoring treatment for each patient.publishedVersio

På tur i det audiodramatiske landskab: Audio Drama Seminar 19.-20. august 2014

På tur i det audiodramatiske landska

Kjønnsroller i endring? : Kvinnelige entreprenører og selvstendig næringsdrivende i Kristiansand 1850-1910

Master's thesis in History (HI500