Developing effective fractionation methods remains challenging in biorefining. γ-Valerolactone (GVL) is a promising green solvent, yet its application in softwood biorefineries is still underexplored. In this study, GVL pretreatment for softwood biorefining was assessed at laboratory and pilot scales. The effects of temperature (170–210 °C), time (20–60 min), and GVL-to-water ratios (20:80 – 80:20 %) on the biorefining of spruce sawdust were initially investigated through lab-scale experiments using a 1-L reactor. A GVL/water solution at a 40:60 ratio, assisted by 0.4 g of sulfuric acid per 100 g of biomass, enabled the solubilization of up to 81.4 % of lignin and nearly the entire hemicellulosic fraction, while effectively preserving cellulose, which was subsequently saccharified with over 90 % conversion. Lignin was regenerated from the liquors and characterized using pyrolysis-gas chromatography/mass spectrometry, high-performance size-exclusion chromatography, Fourier-transform infrared spectroscopy, and 1H-13C heteronuclear single-quantum coherence nuclear magnetic resonance spectroscopy. The biorefinery concept was successfully scaled up and validated at pilot scale in a 50-L reactor, where enzymatic saccharification of the resulting cellulosic pulp produced hydrolysates that, upon fermentation, yielded 231.4 g of ethanol per kilogram of pulp. Lignin regenerated from the pilot-scale pretreatment liquors (118.9 g per kilogram of raw sawdust) and the lignin-rich saccharification residue (182.7 g/kg) were subjected to hydrothermal liquefaction, and the resulting biocrudes were characterized to assess their potential for biofuel formulation. The study showed the suitability of GVL for spruce biorefining to achieve high recovery of digestible cellulose, lignin and hemicelluloses fractions, that are subsequently valuable for chemicals and fuels production

Synthetic routes to sustainable aviation fuels are needed to mitigate the environmental impacts of the aviation sector. Among several emerging methods, the use of light-driven reactions benefits from milder conditions and the possibility of using sunlight to directly irradiate reactants or, alternatively, to power LEDs with a high and constant light intensity. Dinaphthylketone-photosensitized dimerization of isoprene can afford C<inf>10</inf> cycloalkenes that, after hydrogenation, meet the required properties for jet fuels (strongly resembling Jet-A). Isoprene can be photobiologically produced by metabolically engineered cyanobacteria from the conversion of CO<inf>2</inf> and water by utilizing solar light, contributing to a carbon-neutral process. The scale-up of such a combined photobiological-photochemical route is essential to bring it closer to the commercial level. Herein, we present the optimization and scale-up of the photosensitized dimerization of isoprene. By designing different reactor setups, flow versus no-flow conditions, and LED lamps (λ<inf>max</inf> = 365 nm) versus sunlight as the light source, we reached a 2.6 L scale able to produce 61 mL of isoprene dimers per hour, which represents a 14-fold higher productivity compared to our previous results at a smaller scale. We also demonstrated a continuous feed process that converted isoprene into dimers with a 95% yield under LED irradiation. These advancements highlight the potential of light-driven processes to contribute to the energy transition and production of sustainable aviation fuels, making them more viable for commercial use and significantly reducing the environmental impact of the aviation sector.

The biomass potential in Swedish agriculture needs to be used more effectively to produce food, feed and energy in the future and to meet Swedish sustainability goals by 2030. In the project, a biorefinery concept was designed, that consists of the three processes biogas, ley protein and bio-oil. The concept was evaluated with costs and mass balances regionally for Västra Götaland Region. Lab scale trials to produce bio-oil and biogas were also carried out. The results showed that the concept has potential to produce biofuel, protein feed and plant nutrition from agricultural residues and the cultivation of ley and create a high degree of self-sufficiency. However, a more in-depth techno-economic analysis is required as well as an analysis of possible obstacles and bottlenecks. 

The biomass potential in Swedish agriculture needs to be used more effectively to produce food, feed and energy in the future and to meet Swedish sustainability goals by 2030. In the project, a biorefinery concept was designed, that consists of the three processes biogas, ley protein and bio-oil. The concept was evaluated with costs and mass balances regionally for Västra Götaland Region. Lab scale trials to produce bio-oil and biogas were also carried out. The results showed that the concept has potential to produce biofuel, protein feed and plant nutrition from agricultural residues and the cultivation of ley and create a high degree of self-sufficiency. However, a more in-depth techno-economic analysis is required as well as an analysis of possible obstacles and bottlenecks. 

The rise in global temperature and accumulation of petroleum-based wastes in the environment forces the scientific focus towards renewable alternatives. In the present work, an under-exploited resource – spruce bark – is investigated as a raw material for production of bio-oil as a liquid energy carrier. To enhance the energy-content of the produced bio-crude, ultimately being produced through hydrothermal liquefaction, the polysaccharides were extracted through organosolv fractionation and converted to lipids by oleaginous microorganisms. The effect originating from tannins was also investigated by performing a pre-extraction before the organosolv fractionation. It was found that performing the organosolv fractionation and upgrading the isolated organosolv lignin to bio-oil greatly reduced the oxygen content of the oil fraction thereby improving its energy content, and introducing upgraded polysaccharides in the form of lipids, as well as pre-extracted tannins, caused clear changes in the product distribution of the final bio-oil and kept a final product with low oxygen content. The other factor largely influencing the product distribution originated from the various heating rates tested by altering operational mode of the HTL process between batch and semi-continuous. Ultimately, performing the organosolv fractionation and individual upgrading of the polysaccharides had a beneficial effect on reducing the final solids content and enhancing the liquid oil yield. 

Agricultural Biorefinery - combining local and regional scale In order to achieve Sweden's sustainability goals and an increased degree of self-sufficiency, our resources need to be used in an innovative way. Resources that today are classified as residual streams can be used in a smarter way to produce the future's food, feed, fuel and energy. There is a great potential in utilizing agricultural biomasses. In the project, the potential of agriculture to supply ILUC-free feedstock to a local and regional biorefinery concept was calculated and the system was evaluated through mass and energy flow calculations, cost calculations and case descriptions on Vårgårda Herrljunga Biogas Plant (VH Biogas). In addition, practical tests were carried out on bio-oil production from dewatered digestate from participating biogas plants. Quantifications were also carried out of how the concept contributes to more resource-efficient crop cultivation with maintained humus content in soil despite increased removal of biomass from the farm. ...

Conversion of organosolv lignins isolated with and without an inorganic acid catalyst (H2SO4) from hard- and softwood (birch and spruce) into bio-oil through hydrothermal liquefaction has been investigated. Furthermore, fractions of the isolated bio-oils were catalytically deoxygenated to improve the bio-oil properties. As elucidated through NMR, both biomass source and extraction mode influence the bio-oil product distribution. Depending on whether the lignins carry a high content of native structures, or are depolymerized and subsequently condensed in the presence of sugar dehydration products, will dictate heavy oil (HO) and light oil (LO) distribution, and skew the HO product composition, which again will influence the requirements upon catalytical deoxygenation.

Grass-clover ley holds an importance role for a sustainable crop production and is mainly used as feed for ruminants. But ley also contains proteins, if extracted, suitable for monogastric animals such as pigs and poultry. If these proteins are extracted, the degree of self-sufficiency of proteins in Sweden can increase and better resource utilization is achieved. In this study we evaluated the utilization of fresh and ensiled grass-clover ley in a straw-based agricultural biorefinery for producing protein concentrate, ethanol, bio-oil and biogas.

Practical lab scale tests of extraction of high value components for food and feed applications from the liquid fraction after ley pressing were carried out. Pretreatments of the solid fraction prior to ethanol fermentation, bio-oil production using HTL (hydrothermal liquefaction) and biogas production were tested. The system for production and supply of the ley was described and the potential for increased ley production in Sweden was quantified. The environmental and economic efficiency of the proposed biorefinery system was evaluated using environmental systems analysis and technoeconomic assessment.

In terms of system profitability, a high protein yield in the extracted protein concentrate it is important. To achieve that, a thorough pre-treatment using mechanical biomass disintegration before fractioning is crucial. This may need to be done in several steps. Screw pressing is a common technique for fractionating ley into a liquid and solid fraction. Double pressing combined with enzymatic treatments or only water addition during the second pressing stage were found to increase the protein yield compared to single pressing. Second pressing had no effect on the amino acid profile of the protein concentrate.

After pressing fresh ley, heat coagulation or isoelectric precipitation can be used to precipitate protein concentrates in one- or two-step processes to produce protein fractions with different functional properties. Tests showed that it is possible to recover chlorophyll and carotenoids from the ley using supercritical carbon dioxide extraction. which is a suitable method for food applications as toxic organic solvents can be avoided. The ensiling process degrades the protein into smaller peptides or free amino acids which makes ensiled grass less suitable for protein recovery by heat coagulation or isoelectric precipitation. Fresh and ensiled timothy and meadow fescue showed a similar amino acid profile as soybeans.

The initial hypothesis that mechanical pressing may disintegrate the lignocellulosic structure of ley sufficiently to produce a sugar stream with a high concentration of sugar for further fermentation by enzymatic hydrolysis was not confirmed. The content of sugars released after the enzymatic hydrolysis was relatively low. The fibre fraction after the mechanical pressing can be suitable for ethanol production if an additional pretreatment method will be incorporated. Fermentation of pressed and steam-exploded ensiled mixed ley showed promising results. The bio-oils produced with the HTL-process were described of high quality, i.e., high carbon content and low ash content. Although, the obtained materials are not directly integrable in today's refineries, the ensiling did not seem to affect the material's potential for biofuel production. The methane potential tests that were carried out in the project of the liquid residual fraction after protein extraction and after the HTL process showed that both can be suitable for methane production, but they showed great behavior differences.

The results from the environmental system analysis showed that extraction of high-quality products from ley, straw and sawdust according to the studied system reduces climate impact (CO2 eq) when the use of ethanol, bio-oil and biogas replaces fossil fuels, protein concentrate replaces soy as feed and carbon dioxide replaces fossil carbon dioxide. At present, the climate impact from extracted protein concentrate is higher than for soybean meal. Grass source for protein extraction followed by ethanol and bio-oil production as an alternative to straw-based ethanol and bio-oil production did not seem to improve the profitability of the studied biorefinery system. Profitability may be improved if protein extraction is performed the whole all year and not seasonal. Higher prices of the extracted protein concentrate may also improve profitability.

The potential for increased grassland cultivation in Sweden for biorefining was estimated at approximately 3.4 million tonnes grass per year. This included incorporating grassland in the crop rotation in grain-dominated areas, intensification of existing grassland cultivation, utilization of fallow and abandoned arable land for grassland cultivation.

Based on the results and the experience acquired from this project, we suggest an extraction plant for grass-clover ley that operates for both fresh and ensiled grassland all year. The plant needs to be supplemented with more advanced technologies such as membrane filtration for the extraction of amino acids from the ensiled ley during the winter season. The protein extraction plants should be located near farms. The extraction plant is also suggested to be located together with a biogas plant to enable co-digesting residual fractions with manure. Thereby, enabling plant nutrients and minerals in digestate to be returned to arable land. Utilizing the solid fiber fraction for biofuel production with fermentation and HTL in large-scale processes remains promising.

Phosphorus (P) recovery from P-rich residues is crucial to sustain food and industrial demands globally, as phosphate rock reserves are being depleted. The aim of this study is to investigate the speciation and recovery of P from hydrochars (HC) of a metal-bearing sewage sludge (SS) produced by hydrothermal carbonization (HTC). We here focus on extractions by acid leaching as P cannot be directly recovered by HTC due to insoluble metal-P compounds. Acid leaching of SS and HCs was investigated using H2SO4 and HCl over a range of leaching times, and explained in terms of how composition affects P and metal release efficiency. HTC at 180, 215 and 250 °C showed that P remained immobilized (&gt; 75% of total P) in the HCs. More than 95% was present as inorganic P, and was the direct consequence of the double addition of iron salts in the wastewater treatment plant. Leaching experiments in 2.5 M acid solutions showed that a near complete release of P could be achieved in HCs, while it was only incomplete in SS (up to 85%). Lower acid concentrations were ineffective for total P recovery. Treatment temperature exceeding 180 °C however decreased P release rates, such that total removal took at least 2 h of reaction time instead of a few minutes. On the other hand, acid leaching transferred more than 70% of iron, manganese, copper and zinc into the leachate, necessitating a post-treatment purification process. This work therefore reveals that HC produced at low HTC temperatures could offer promising avenues for time- and energy-efficient P recovery from SS. Graphic Abstract: [Figure not available: see fulltext.] © 2021, The Author(s).

AGROinLOG project has tested the integrated biomass logistics centres (IBLC) concept in three real agro-industries in Europe. The relevance of the IBLC strategy relies on the fact that it allows agro-industries to create a new activity with lower investment, increasing incomes, stabilizing their annual activity (avoiding idle periods) and maintaining or creating new jobs. The demos’ studies were performed in Spain at a fodder industry, in Greece at an olive oil industry, and in Sweden inside a cereal processing industry. AGROinLOG validated these demos´ business models from a holistic perspective, also studying the replicability of the IBLC business model in other agro-industries from different sectors (vegetable oil extraction, olive oil chain, feed & fodder, wine, grain chain and sugar industry). Sectorial analysis was carried out as well, allowing the identification of opportunities among the targeted sector to replicate the IBLC concept, drawing barriers to overcome in each case. Thus, technical, economic and environmental feasibility of integrated biomass logistics centers (IBLCs) for food and non-food products have been assessed in detail.