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  • 1.
    Alriksson, Björn
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Processum.
    Cavka, Adnan
    Umeå University, Sweden.
    Jönsson, Leif J.
    Umeå University, Sweden.
    Improving the fermentability of enzymatic hydrolysates of lignocellulose through chemical in-situ detoxification with reducing agents2011Inngår i: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 102, nr 2, s. 1254-1263Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Inhibitory lignocellulose hydrolysates were treated with the reducing agents dithionite and sulfite to achieve improved fermentability. Addition of these reducing agents (in the concentration range 5.0-17.5mM) to enzymatic hydrolysates of spruce wood or sugarcane bagasse improved processes based on both SHF (simultaneous hydrolysis and fermentation) and SSF (simultaneous saccharification and fermentation). The approach was exemplified in ethanolic fermentations with Saccharomyces cerevisiae and by using hydrolysates with sugar concentrations >100g/L (for SHF) and with 10% dry-matter content (for SSF). In the SHF experiments, treatments with dithionite raised the ethanol productivities of the spruce hydrolysate from 0.2 to 2.5g×L -1×h -1 and of the bagasse hydrolysate from 0.9 to 3.9g×L -1×h -1, values even higher than those of fermentations with reference sugar solutions without inhibitors. Benefits of the approach include that the addition of the reducing agent can be made in-situ directly in the fermentation vessel, that the treatment can be performed at a temperature and pH suitable for fermentation, and that the treatment results in dramatically improved fermentability without degradation of fermentable sugars. The many benefits and the simplicity of the approach offer a new way to achieve more efficient manufacture of fermentation products from lignocellulose hydrolysates. 

  • 2.
    Alriksson, Björn
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Processum.
    Eskilsson, Martin
    Holmen, Sweden.
    Johansson, Emma
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Processum.
    Lapidot, Shaul
    Melodea, Israel.
    Norström, Markus
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Schultz-Eklund, Ola
    Holmen, Sweden .
    Shkedi, Yoram
    Melodea, Israel.
    Svedberg, Anna
    MoRe Research, Sweden.
    Svensson, Stefan
    MoRe Research, Sweden.
    Swerin, Agne
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Material och ytteknik.
    Europe’s first pilot facility for cellulose nanocrystals (CNC)2016Inngår i: Annual Surface and Materials Chemistry Symposium and Materials for tomorrow (ASMCS 2016), 2016Konferansepaper (Fagfellevurdert)
  • 3.
    Alriksson, Björn
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Processum.
    Hörnberg, Andreas
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Gudnason, Asgeir Eirikur
    Saebyli Ehf, Iceland.
    Knobloch, Stephen
    Matis, Iceland.
    Arnason, Jon
    Matis, Iceland.
    Johannsson, Ragnar
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Fish feed from wood2014Inngår i: Cellulose Chemistry and Technology, ISSN 0576-9787, Vol. 48, s. 843-848Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Increased demand of fish in combination with overexploitation of the fish stocks of the oceans has led to an increased production of fish through aquaculture. Today, fishmeal is the main protein source in fish feed for most aquaculture species. However, fishmeal is soon expected to fall short of demand as its production is associated with environmental problems. This shortage must therefore be met by sustainable alternative protein sources. Protein-rich microorganisms (i.e. Single cell protein) is an interesting option as a fishmeal substitute in fish feed which, in addition, can be produced as an important co-product in wood-based biorefineries. In the current study, four different microorganisms were cultivated on five different residual streams from Swedish wood-based biorefineries. Screening experiments were carried out in shake flasks, optimization experiments in benchtop bioreactors, and scale-up experiments were performed in a 50-litre pilot bioreactor. In addition, a demo-scale experiment was carried out in the Swedish Biorefinery Demo Plant. Microbial biomass from the scale-up experiments was collected and used for production of different fish feed formulations which, in turn, were used in feeding trials of the freshwater fish Tilapia. Fishes fed with feed, in which part of the fishmeal had been substituted with Single cell protein, showed similar or better growth than fishes fed with a fishmeal-based control feed.

  • 4.
    Alriksson, Björn
    et al.
    Karlstad University, Sweden.
    Rose, S. H.
    University of Stellenbosch, South Africa.
    Van Zyl, W. H.
    University of Stellenbosch, South Africa.
    Sjöde, A.
    Karlstad University, Sweden.
    Nilvebrant, N. -O
    RISE., STFI-Packforsk. Karlstad University, Sweden.
    Jönsson, L. J.
    Karlstad University, Sweden; Umeå University, Sweden.
    Cellulase production from spent lignocellulose hydrolysates by recombinant aspergillus niger2009Inngår i: Applied and Environmental Microbiology, ISSN 0099-2240, E-ISSN 1098-5336, Vol. 75, nr 8, s. 2366-2374Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A recombinant Aspergillus niger strain expressing the Hypocrea jecorina endoglucanase Cel7B was grown on spent hydrolysates (stillage) from sugarcane bagasse and spruce wood. The spent hydrolysates served as excellent growth media for the Cel7B-producing strain, A. niger D15[egI], which displayed higher endoglucanase activities in the spent hydrolysates than in standard medium with a comparable monosaccharide content (e.g., 2,100 nkat/ml in spent bagasse hydrolysate compared to 480 nkat/ml in standard glucose-based medium). In addition, A. niger D15[egI] was also able to consume or convert other lignocellulose-derived compounds, such as acetic acid, furan aldehydes, and phenolic compounds, which are recognized as inhibitors of yeast during ethanolic fermentation. The results indicate that enzymes can be produced from the stillage stream as a high-value coproduct in secondgeneration bioethanol plants in a way that also facilitates recirculation of process water.

  • 5.
    Berglin, Niklas
    et al.
    RISE., Innventia.
    von Schenck, Anna
    RISE., Innventia.
    Alriksson, Björn
    Hörnberg, Andreas
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Lindstedt, J
    Östman, J
    POLYNOL - chemical intermediates from renewable sources2014Konferansepaper (Fagfellevurdert)
  • 6.
    Bergman, Kristina
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Jordbruk och livsmedel. KTH Royal Institute of Technology, Sweden.
    Woodhouse, Anna
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Jordbruk och livsmedel.
    Langeland, Markus
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Jordbruk och livsmedel. SLU Swedish University of Agricultural Sciences, Sweden.
    Vidakovic, Aleksandar
    SLU Swedish University of Agricultural Sciences, Sweden.
    Alriksson, Björn
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Hornborg, Sara
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Jordbruk och livsmedel.
    Environmental and biodiversity performance of a novel single cell protein for rainbow trout feed2024Inngår i: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 907, artikkel-id 168018Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Seafood has an important role to play to achieve a sustainable food system that provides healthy food to a growing world population. Future seafood production will be increasingly reliant on aquaculture where feed innovation is essential to reduce environmental impacts and minimize feed and food competition. This study aimed to investigate whether a novel single cell protein feed ingredient based on Paecilomyces variotii grown on a side stream from the forest industry could improve environmental sustainability of farmed rainbow trout (Oncorhynchus mykiss) by replacing the soy protein concentrate used today. A Life Cycle Assessment including commonly addressed impacts but also the rarely assessed biodiversity impacts was performed. Furthermore, feeding trials were included for potential effects on fish growth, i.e., an assessment of the environmental impacts for the functional unit ‘kg feed required to produce 1 kg live-weight rainbow trout’. Results showed that the best experimental diet containing P. variotii performed 16–73 % better than the control diet containing soy protein concentrate in all impact categories except for energy demand (21 % higher impact). The largest environmental benefits from replacing soy protein with P. variotii in rainbow trout diets was a 73 % reduction of impact on biodiversity and halved greenhouse gas emissions. The findings have high relevance for the aquaculture industry as the production scale and feed composition was comparable to commercial operations and because the effect on fish growth from inclusion of the novel ingredient in a complete diet was evaluated. The results on biodiversity loss from land use change and exploitation through fishing suggest that fishery can dominate impacts and exclusion thereof can greatly underestimate biodiversity impact. Finally, a novel feed ingredient grown on side streams from the forest industry has potential to add to food security through decreasing the dependence on increasingly scarce agricultural land resources. 

  • 7.
    Cavka, Adnan
    et al.
    Umeå University, Sweden.
    Alriksson, Björn
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Processum.
    Ahnlund, Maria
    SLU Swedish University of Agricultural Sciences, Sweden.
    Jönsson, Leif J.
    Umeå University, Sweden.
    Effect of sulfur oxyanions on lignocellulose-derived fermentation inhibitors2011Inngår i: Biotechnology and Bioengineering, ISSN 0006-3592, E-ISSN 1097-0290, Vol. 108, nr 11, s. 2592-2599Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Recent results show that treatments with reducing agents, including the sulfur oxyanions dithionite and hydrogen sulfite, efficiently improve the fermentability of inhibitory lignocellulose hydrolysates, and that the treatments are effective when the reducing agents are added in situ into the fermentation vessel at low temperature. In the present investigation, dithionite was added to medium with model inhibitors (coniferyl aldehyde, furfural, 5-hydroxymethylfurfural, or acetic acid) and the effects on the fermentability with yeast were studied. Addition of 10mM dithionite to medium containing 2.5mM coniferyl aldehyde resulted in a nine-fold increase in the glucose consumption rate and a three-fold increase in the ethanol yield. To investigate the mechanism behind the positive effects of adding sulfur oxyanions, mixtures containing 2.5mM of a model inhibitor (an aromatic compound, a furan aldehyde, or an aliphatic acid) and 15mM dithionite or hydrogen sulfite were analyzed using mass spectrometry (MS). The results of the analyses, which were performed by using UHPLC-ESI-TOF-MS and UHPLC-LTQ/Orbitrap-MS/MS, indicate that the positive effects of sulfur oxyanions are primarily due to their capability to react with and sulfonate inhibitory aromatic compounds and furan aldehydes at low temperature and slightly acidic pH (such as 25°C and pH 5.5).

  • 8.
    Cavka, Adnan
    et al.
    Umeå University, Sweden.
    Alriksson, Björn
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Processum.
    Rose, Shaunita H.
    Stellenbosch University, South Africa.
    Van Zyl, Willem H.
    Stellenbosch University, South Africa.
    Jönsson, Leif J.
    Umeå University, Sweden.
    Biorefining of wood: Combined production of ethanol and xylanase from waste fiber sludge2011Inngår i: Journal of Industrial Microbiology & Biotechnology, ISSN 1367-5435, E-ISSN 1476-5535, Vol. 38, nr 8, s. 891-899Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The possibility to utilize fiber sludge, waste fibers from pulp mills and lignocellulose-based biorefineries, for combined production of liquid biofuel and biocatalysts was investigated. Without pretreatment, fiber sludge was hydrolyzed enzymatically to monosaccharides, mainly glucose and xylose. In the first of two sequential fermentation steps, the fiber sludge hydrolysate was fermented to cellulosic ethanol with the yeast Saccharomyces cerevisiae. Although the final ethanol yields were similar, the ethanol productivity after 9.5 h was 3.3 g/l/h for the fiber sludge hydrolysate compared with only 2.2 g/l/h for a reference fermentation with similar sugar content. In the second fermentation step, the spent fiber sludge hydrolysate (the stillage obtained after distillation) was used as growth medium for recombinant Aspergillus niger expressing the xylanase-encoding Trichoderma reesei (Hypocrea jecorina) xyn2 gene. The xylanase activity obtained with the spent fiber sludge hydrolysate (8,500 nkat/ml) was higher than that obtained in a standard medium with similar monosaccharide content (1,400 nkat/ml). Analyses based on deglycosylation with N-glycosidase F suggest that the main part of the recombinant xylanase was unglycosylated and had molecular mass of 20.7 kDa, while a minor part had N-linked glycosylation and molecular mass of 23.6 kDa. Chemical analyses of the growth medium showed that important carbon sources in the spent fiber sludge hydrolysate included xylose, small aliphatic acids, and oligosaccharides. The results show the potential of converting waste fiber sludge to liquid biofuel and enzymes as coproducts in lignocellulose-based biorefineries. 

  • 9.
    Cavka, Adnan
    et al.
    Umeå University, Sweden.
    Alriksson, Björn
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Processum.
    Rose, Shaunita H.
    Stellenbosch University, South Africa.
    Van Zyl, Willem H.
    Stellenbosch University, South Africa.
    Jönsson, Leif J.
    Umeå University, Sweden.
    Production of cellulosic ethanol and enzyme from waste fiber sludge using SSF, recycling of hydrolytic enzymes and yeast, and recombinant cellulase-producing Aspergillus niger2014Inngår i: Journal of Industrial Microbiology & Biotechnology, ISSN 1367-5435, E-ISSN 1476-5535, Vol. 41, nr 8, s. 1191-1200Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Bioethanol and enzymes were produced from fiber sludges through sequential microbial cultivations. After a first simultaneous saccharification and fermentation (SSF) with yeast, the bioethanol concentrations of sulfate and sulfite fiber sludges were 45.6 and 64.7 g/L, respectively. The second SSF, which included fresh fiber sludges and recycled yeast and enzymes from the first SSF, resulted in ethanol concentrations of 38.3 g/L for sulfate fiber sludge and 24.4 g/L for sulfite fiber sludge. Aspergillus niger carrying the endoglucanase-encoding Cel7B gene of Trichoderma reesei was grown in the spent fiber sludge hydrolysates. The cellulase activities obtained with spent hydrolysates of sulfate and sulfite fiber sludges were 2,700 and 2,900 nkat/mL, respectively. The high cellulase activities produced by using stillage and the significant ethanol concentrations produced in the second SSF suggest that onsite enzyme production and recycling of enzyme are realistic concepts that warrant further attention.

  • 10.
    Chen, Genqiang
    et al.
    Shanghai University, China; Umeå University, Sweden.
    Wu, Guochao
    Umeå University, Sweden.
    Alriksson, Björn
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi, Processum.
    Chen, Lin
    Donghua University, China.
    Wang, Wei
    Donghua University, China.
    Jönsson, Leif
    Umeå University, Sweden.
    Hong, Feng
    Umeå University, Sweden.
    Scale-up of production of bacterial nanocellulose using submerged cultivation2018Inngår i: Journal of chemical technology and biotechnology (1986), ISSN 0268-2575, E-ISSN 1097-4660, Vol. 93, nr 12, s. 3418-3427Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND: More extensive utilization of bacterial nanocellulose (BNC) is severely restricted by the low efficiency and small scale of the traditional static cultivation. Submerged fermentation in stirred-tank reactors (STRs) is potentially favourable for large-scale production of BNC, but scale-up of cultivation remains challenging. Even though the STR is most commonly used for submerged cultivation in the fermentation industry, there are few previous attempts to scale-up production of BNC to pilot scale using an STR. Furthermore, the question of how scale-up of submerged cultivation affects the properties of the BNC has received very little attention. RESULTS: Four strains were compared in 250-mL shake flasks. Strain DHU-ATCC-1 displayed the highest volumetric productivity, 0.56 g L−1 d−1, and was then cultivated in a 400-mL STR, showing a similar productivity of 0.55 g L−1 d−1. Scale-up using a 75-L STR pilot bioreactor resulted in enhancement of the BNC production rate from 0.056 g d−1 in the shake flasks to 17.3 g d−1 in the 75-L STR, although the productivity decreased to 0.43 g L−1 d−1. During scale-up from shake flasks to 400-mL STR and further on to 75-L STR, the BNC fibers formed more bundles, whereas the fiber diameter decreased from 25.6 to 21.7 nm. The BNC from the 75-L STR exhibited a higher degree of polymerization, specifically 3230, higher degree of crystallinity, specifically 83%, larger crystallites, and improved strength including higher tensile energy absorption index and superior stretch at break. CONCLUSION: It is possible to enhance BNC production, and maintain or improve its properties when scaling up submerged cultivation in STRs.

  • 11.
    Chen, Genqiang
    et al.
    Donghua University, China; Umeå University, Sweden.
    Wu, Guochao
    Umeå University, Sweden.
    Alriksson, Björn
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi, Processum.
    Wang, Wei
    Donghua University, China.
    Hong, Feng F.
    Donghua University, China.
    Jönsson, Leif J.
    Umeå University, Sweden.
    Bioconversion of waste fiber sludge to bacterial nanocellulose and use for reinforcement of CTMP paper sheets2017Inngår i: Polymers, E-ISSN 2073-4360, Vol. 9, nr 9, artikkel-id 458Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Utilization of bacterial nanocellulose (BNC) for large-scale applications is restricted by low productivity in static cultures and by the high cost of the medium. Fiber sludge, a waste stream from pulp and paper mills, was enzymatically hydrolyzed to sugar, which was used for the production of BNC by the submerged cultivation of Komagataeibacter xylinus. Compared with a synthetic glucose-based medium, the productivity of purified BNC from the fiber sludge hydrolysate using shake-flasks was enhanced from 0.11 to 0.17 g/(L × d), although the average viscometric degree of polymerization (DPv) decreased from 6760 to 6050. The cultivation conditions used in stirred-tank reactors (STRs), including the stirring speed, the airflow, and the pH, were also investigated. Using STRs, the BNC productivity in fiber-sludge medium was increased to 0.32 g/(L × d) and the DPv was increased to 6650. BNC produced from the fiber sludge hydrolysate was used as an additive in papermaking based on the chemithermomechanical pulp (CTMP) of birch. The introduction of BNC resulted in a significant enhancement of the mechanical strength of the paper sheets. With 10% (w/w) BNC in the CTMP/BNC mixture, the tear resistance was enhanced by 140%. SEM images showed that the BNC cross-linked and covered the surface of the CTMP fibers, resulting in enhanced mechanical strength.

  • 12.
    Donev, E. N.
    et al.
    SLU Swedish University of Agricultural Sciences, Sweden.
    Derba-Maceluch, M.
    SLU Swedish University of Agricultural Sciences, Sweden.
    Yassin, Zakiya
    RISE Research Institutes of Sweden, Samhällsbyggnad, Bygg och fastighet.
    Gandla, M. L.
    Umeå University, Sweden.
    Pramod, S.
    SLU Swedish University of Agricultural Sciences, Sweden; KTH Royal Institute of Technology, Sweden.
    Heinonen, E.
    KTH Royal Institute of Technology, Sweden.
    Kumar, V.
    SLU Swedish University of Agricultural Sciences, Sweden.
    Scheepers, Gerhard
    RISE Research Institutes of Sweden, Samhällsbyggnad, Bygg och fastighet.
    Vilaplana, F.
    KTH Royal Institute of Technology, Sweden.
    Johansson, U.
    SLU Swedish University of Agricultural Sciences, Sweden.
    Hertzberg, M.
    SweTree Technologies AB, Sweden.
    Sundberg, B.
    SLU Swedish University of Agricultural Sciences, Sweden.
    Winestrand, S.
    Umeå University, Sweden.
    Hörnberg, Andreas
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Alriksson, Björn
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Jönsson, L. J.
    Umeå University, Sweden.
    Mellerowicz, E. J.
    SLU Swedish University of Agricultural Sciences, Sweden.
    Field testing of transgenic aspen from large greenhouse screening identifies unexpected winners2023Inngår i: Plant Biotechnology Journal, ISSN 1467-7644, E-ISSN 1467-7652, Vol. 21, nr 5, s. 1005-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Trees constitute promising renewable feedstocks for biorefinery using biochemical conversion, but their recalcitrance restricts their attractiveness for the industry. To obtain trees with reduced recalcitrance, large-scale genetic engineering experiments were performed in hybrid aspen blindly targeting genes expressed during wood formation and 32 lines representing seven constructs were selected for characterization in the field. Here we report phenotypes of five-year old trees considering 49 traits related to growth and wood properties. The best performing construct considering growth and glucose yield in saccharification with acid pretreatment had suppressed expression of the gene encoding an uncharacterized 2-oxoglutarate-dependent dioxygenase (2OGD). It showed minor changes in wood chemistry but increased nanoporosity and glucose conversion. Suppressed levels of SUCROSE SYNTHASE, (SuSy), CINNAMATE 4-HYDROXYLASE (C4H) and increased levels of GTPase activating protein for ADP-ribosylation factor ZAC led to significant growth reductions and anatomical abnormalities. However, C4H and SuSy constructs greatly improved glucose yields in saccharification without and with pretreatment, respectively. Traits associated with high glucose yields were different for saccharification with and without pretreatment. While carbohydrates, phenolics and tension wood contents positively impacted the yields without pretreatment and growth, lignin content and S/G ratio were negative factors, the yields with pretreatment positively correlated with S lignin and negatively with carbohydrate contents. The genotypes with high glucose yields had increased nanoporosity and mGlcA/Xyl ratio, and some had shorter polymers extractable with subcritical water compared to wild-type. The pilot-scale industrial-like pretreatment of best-performing 2OGD construct confirmed its superior sugar yields, supporting our strategy. © 2023 The Authors. 

  • 13.
    Ilanidis, Dimitrios
    et al.
    Umeå University, Sweden.
    Stagge, Stefan
    Umeå University, Sweden.
    Alriksson, Björn
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Cavka, Adnan
    SEKAB E-Technology AB, Sweden.
    Jönsson, Leif
    Umeå University, Sweden.
    Comparison of Efficiency and Cost of Methods for Conditioning of Slurries of Steam-Pretreated Softwood2021Inngår i: Frontiers in Energy Research, E-ISSN 2296-598X, Vol. 9, artikkel-id 701980Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Inhibitors formed during pretreatment impair lignocellulose bioconversion by making enzymatic saccharification and microbial fermentation less efficient, but conditioning of slurries and hydrolysates can improve fermentability and sometimes also enzymatic digestibility. Conditioning of pretreated softwood using four industrial reducing agents (sodium sulfite, sodium dithionite, sodium borohydride, and hydrogen) was compared with standard methods, such as overliming and treatment with activated charcoal. A dosage of approx. 1 mM sulfur oxyanion (sulfite or dithionite) per percent water-insoluble solids (WIS) in the slurry was found to result in good fermentability. Treatment of 10–20% WIS slurries with 15 mM sulfur oxyanion under mild reaction conditions (23°C, pH 5.5) resulted in sulfonation of the solid phase and saccharification improvements of 18–24% for dithionite and 13–16% for sulfite. Among the different conditioning methods studied, treatment of slurries with sodium sulfite was superior with respect to cost-efficient improvement of fermentability. Treatments of slurry or pretreatment liquid with 15 mM sulfite or dithionite resulted in 58–76% reduction of the content of formaldehyde. The comparison indicates that conditioning of pretreated biomass using sulfur oxyanions warrants further attention. 

  • 14.
    Ilanidis, Dimitrios
    et al.
    Umeå University, Sweden.
    Stagge, Stefan
    Umeå University, Sweden.
    Alriksson, Björn
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Jönsson, Leif
    Umeå University, Sweden.
    Factors affecting detoxification of softwood enzymatic hydrolysates using sodium dithionite2021Inngår i: Processes, ISSN 2227-9717, Vol. 9, nr 5, artikkel-id 887Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Conditioning of lignocellulosic hydrolysates with sulfur oxyanions, such as dithionite, is one of the most potent methods to improve the fermentability by counteracting effects of inhibitory by-products generated during hydrothermal pretreatment under acidic conditions. The effects of pH, treatment temperature, and dithionite dosage were explored in experiments with softwood hydrolysates, sodium dithionite, and Saccharomyces cerevisiae yeast. Treatments with dithionite at pH 5.5 or 8.5 gave similar results with regard to ethanol productivity and yield on initial glucose, and both were always at least ~20% higher than for treatment at pH 2.5. Experiments in the dithionite concentration range 5.0–12.5 mM and the temperature range 23–110◦ C indicated that treatment at around 75◦ C and using intermediate dithionite dosage was the best option (p ≤ 0.05). The investigation indicates that selection of the optimal temperature and dithionite dosage offers great benefits for the efficient fermentation of hydrolysates from lignin-rich biomass, such as softwood residues. © 2021 by the authors. 

  • 15.
    Jönsson, Leif J.
    et al.
    Umeå University, Sweden.
    Alriksson, Björn
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Processum.
    Nilvebrant, Nils-Olof
    Borregaard, Norway.
    Bioconversion of lignocellulose: Inhibitors and detoxification2013Inngår i: Biotechnology for Biofuels, E-ISSN 1754-6834, Vol. 6, nr 1, artikkel-id Art no 16Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Bioconversion of lignocellulose by microbial fermentation is typically preceded by an acidic thermochemical pretreatment step designed to facilitate enzymatic hydrolysis of cellulose. Substances formed during the pretreatment of the lignocellulosic feedstock inhibit enzymatic hydrolysis as well as microbial fermentation steps. This review focuses on inhibitors from lignocellulosic feedstocks and how conditioning of slurries and hydrolysates can be used to alleviate inhibition problems. Novel developments in the area include chemical in-situ detoxification by using reducing agents, and methods that improve the performance of both enzymatic and microbial biocatalysts.

  • 16.
    Smarason, Birgir Örn
    et al.
    Matís Ltd, Iceland.
    Alriksson, Björn
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi, Processum.
    Johannsson, Ragnar
    Marine Research Institute, Iceland.
    Safe and sustainable protein sources from the forest industry - The case of fish feed2019Inngår i: Trends in Food Science & Technology, ISSN 0924-2244, E-ISSN 1879-3053, Vol. 84, s. 12-14Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: Aquaculture represents a solution to the future world demand for healthy protein while challenges that require urgent solutions are emerging in feed production, such as the rising costs of feed protein and massive imports. From a European perspective, a large proportion of the protein demand is met with imported protein. This article will focus on the development of protein-rich microorganisms (i.e. Single cell protein) as a novel raw material in fish feed which can be produced as an important co-product in wood-based biorefineries, increasing sustainability and the utilization of organic waste material. Scope and Approach: Developing a safe and sustainable protein resource from local organic waste-material represents an opportunity for Europe to decrease its reliance on nutritional imports, and address mounting food sector sustainability concerns and a growing protein deficit. At the same time, the nutrient recycling industry represents a growing industry, addressing waste valorization and protein feed production concerns at once. Key Findings and Conclusion: An industry and research collaboration has focused on selecting which microorganisms and residual streams from a wood-biorefinery site that would be best suited for production of SCP. The study showed that 38-68% of the fishmeal in a Nile tilapia (Oreochromis niloticus) feed could be replaced with SCP while maintaining a similar or slightly improved fish growth. As reported by FAO, aquaculture production of Nile tilapia in 2014 was 3.7 million tonnes, making it one of the most produced fish species in the world.

  • 17.
    Soudham, Venkata Prabhakar
    et al.
    Umeå University, Sweden.
    Alriksson, Björn
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Processum.
    Jönsson, Leif J.
    Umeå University, Sweden.
    Reducing agents improve enzymatic hydrolysis of cellulosic substrates in the presence of pretreatment liquid2011Inngår i: Journal of Biotechnology, ISSN 0168-1656, E-ISSN 1873-4863, Vol. 155, nr 2, s. 244-250Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Enzymatic hydrolysis of pretreated lignocellulosic substrates has emerged as an interesting option to produce sugars that can be converted to liquid biofuels and other commodities using microbial biocatalysts. Lignocellulosic substrates are pretreated to make them more accessible to cellulolytic enzymes, but the pretreatment liquid partially inhibits subsequent enzymatic hydrolysis. The presence of pretreatment liquid from Norway spruce resulted in a 63% decrease in the enzymatic saccharification of Avicel compared to when the reaction was performed in a buffered aqueous solution. The addition of 15. mM of a reducing agent (hydrogen sulfite, dithionite, or dithiothreitol) to reaction mixtures with the pretreatment liquid resulted in up to 54% improvement of the saccharification efficiency. When the reducing agents were added to reaction mixtures without pretreatment liquid, there was a 13-39% decrease in saccharification efficiency. In the presence of pretreatment liquid, the addition of 15. mM dithionite to Avicel, α-cellulose or filter cake of pretreated spruce wood resulted in improvements between 25 and 33%. Positive effects (6-17%) of reducing agents were also observed in experiments with carboxymethyl cellulose and 2-hydroxyethyl cellulose. The approach to add reducing agents appears useful for facilitating the utilization of enzymes to convert cellulosic substrates in industrial processes. 

  • 18.
    Soudham, Venkata Prabhakar
    et al.
    Umeå University, Sweden.
    Gräsvik, John
    Umeå University, Sweden.
    Alriksson, Björn
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Processum.
    Mikkola, Jyri-Pekka
    Umeå University, Sweden; Åbo Akademi University, Finland.
    Jönsson, Leif J.
    Umeå University, Sweden.
    Enzymatic hydrolysis of Norway spruce and sugarcane bagasse after treatment with 1-allyl-3-methylimidazolium formate2013Inngår i: Journal of chemical technology and biotechnology (1986), ISSN 0268-2575, E-ISSN 1097-4660, Vol. 88, nr 12, s. 2209-2215Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND: Enzymatic hydrolysis of cellulose in lignocellulosic materials suffers from slow reaction rates due to limited access to enzyme adsorption sites and to the high crystallinity of the cellulose. In this study, an attempt was made to facilitate enzymatic hydrolysis by pretreatment of cellulosic materials using the ionic liquid (IL) 1-allyl-3-methylimidazolium formate ([Amim][HCO2]) under mild reaction conditions. The effect of the IL was compared with that of thermochemical pretreatment under acidic conditions. RESULTS: The lignocellulosic substrates investigated were native and thermochemically pretreated Norway spruce and sugarcane bagasse. Microcrystalline cellulose (Avicel) was included for comparison. The IL treatments were performed in the temperature range 45-120°C and, after regeneration and washing of the cellulosic substrates, enzymatic saccharification was carried out at 45°C for 72h. After 12h of hydrolysis, the glucose yields from regenerated native spruce and sugarcane bagasse were up to nine times higher than for the corresponding untreated substrates. The results also show positive effects of pretreatment using [Amim][HCO2] on the hydrolysis of xylan and mannan. Conclusion: The present work demonstrates that both native wood and agricultural residues are readily soluble in [Amim][HCO2] under gentle conditions, and that pretreatment with ionic liquids such as [Amim][HCO2] warrants further attention as a potential alternative to conventional pretreatment techniques.

  • 19.
    Wu, G
    et al.
    Ludong University, China; Umeå University, Sweden.
    Alriksson, Björn
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Jönsson, Leif
    Umeå University, Sweden.
    Conditioning of pretreated birch by liquid-liquid organic extractions to improve yeast fermentability and enzymatic digestibility2023Inngår i: RSC Advances, E-ISSN 2046-2069, Vol. 13, nr 29, s. 20023-20030Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    By-products from hydrothermal pretreatment of lignocellulosic biomass inhibit enzymatic saccharification and microbial fermentation. Three long-chain organic extractants (Alamine 336, Aliquat 336 and Cyanex 921) were compared to two conventional organic solvents (ethyl acetate and xylene) with regard to conditioning of birch wood pretreatment liquid (BWPL) for improved fermentation and saccharification. In the fermentation experiments, extraction with Cyanex 921 resulted in the best ethanol yield, 0.34 ± 0.02 g g−1 on initial fermentable sugars. Extraction with xylene also resulted in a relatively high yield, 0.29 ± 0.02 g g−1, while cultures consisting of untreated BWPL and BWPL treated with the other extractants exhibited no ethanol formation. Aliquat 336 was most efficient with regard to removing by-products, but the residual Aliquat after the extraction was toxic to yeast cells. Enzymatic digestibility increased by 19-33% after extraction with the long-chain organic extractants. The investigation demonstrates that conditioning with long-chain organic extractants has the potential to relieve inhibition of both enzymes and microbes. 

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