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  • 1. Aguilera, Adriana Freites
    et al.
    Tolvanen, Pasi
    Oger, Adrien
    Eränen, Kari
    Leveneur, Sébastien
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Laboratory of Industrial Chemistry and Reaction Engineering, Department of Chemical Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Turku-Åbo, Finland.
    Salmi, Tapio
    Screening of ion exchange resin catalysts for epoxidation of oleic acid under the influence of conventional and microwave heating2019Ingår i: Journal of chemical technology and biotechnology (1986), ISSN 0268-2575, E-ISSN 1097-4660, Vol. 94, nr 9, s. 3020-3031Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: For many chemical systems, it is of great importance to find a durable, active and efficient catalyst that improves the process performance. Epoxidation of oleic acid with peracetic acid (Prilezhaev oxidation) was carried out in an isothermal loop reactor in the presence of heterogeneous catalysts. The kinetic experiments conducted under microwave heating (MW) were compared with identical experiments carried out under conventional (conductive/convective) heating. Extensive screening of heterogeneous catalysts was conducted and the influence of microwave irradiation on the reaction kinetics was studied. Several ion exchange resins were screened to explore their applicability and activity in the epoxidation of oleic acid. The perhydrolysis reaction (peracetic acid formed in situ from acetic acid and H2O2) was promoted with the use of various solid acid catalysts: Amberlite IR-120, Amberlyst 15, Smopex®, Dowex 50x8-100, Dowex 50x8-50, Dowex 50x2-100 and Nafion™.

    Results: From the selected group of catalysts, Dowex 50-x8100 and Dowex 50x8-50 produced the highest yield of epoxidized oil. Only minor differences in the reactant conversion and the product yield were found in the experiments carried out under microwave exposure compared to the conventionally heated experiments in the presence of several ion exchange resins.

    Conclusions: The catalytic effect was much more prominent than the microwave effect, because the solid acid catalysts enhanced the slow step of the process, the perhydrolysis of acetic acid. The catalytic effect was very dominant and a considerable improvement of the oleic acid conversion and the epoxide yield was observed in the presence of the top-performing catalysts.

  • 2.
    Chen, Genqiang
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Department of Bioengineering, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, , Shanghai, China.
    Wu, Guochao
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Alriksson, Björn
    Chen, Lin
    Wang, Wei
    Jönsson, Leif J.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Hong, Feng F.
    Scale-up of production of bacterial nanocellulose using submerged cultivation2018Ingår i: Journal of chemical technology and biotechnology (1986), ISSN 0268-2575, E-ISSN 1097-4660, Vol. 93, nr 12, s. 3418-3427Artikel i tidskrift (Refereegranskat)
    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.

  • 3. Guo, Xiang
    et al.
    Chen, Lin
    Tang, Jingyu
    Jönsson, Leif J.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. China-Sweden Associated Research Laboratory in Industrial Biotechnology,College of Chemistry, Chemical Engineering and Biotechnology, Donghua Uni-versity, Shanghai, 201620, China.
    Hong, Feng F.
    Production of bacterial nanocellulose and enzyme from [AMIM]Cl-pretreated waste cotton fabrics: effects of dyes on enzymatic saccharification and nanocellulose production2016Ingår i: Journal of chemical technology and biotechnology (1986), ISSN 0268-2575, E-ISSN 1097-4660, Vol. 91, nr 5, s. 1413-1421Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND Dyed used cotton textiles is a waste material associated with environmental problems. In this study, waste dyed cotton fabrics were used as feedstock for production of bacterial nanocellulose (BNC) with Gluconacetobacter xylinus and production of enzymes with Trichoderma reesei via enzymatic saccharification.

    RESULTS Reactive dyes caused almost no inhibition of the cellulase activity at a concentration of 5 g L-1, but decreased the BNC production at concentrations higher than 1 g L-1. The BNC yield reached 12.8 g L-1 with cotton hydrolysate, which was 48% higher than with glucose-based medium. The spent fermentation broth after BNC harvest was subsequently utilized for enzyme production. Cellulase activities produced by T. reesei reached 5.3 U mL(-1) with spent detoxified purple bed sheet (PBS) hydrolysate, and 8.2 U mL(-1) with 2-fold diluted spent PBS hydrolysate, which was almost the same or higher than with glucose medium (5.6 U mL(-1)). The xylanase activities (60.2 U mL(-1) and 88.0 U mL(-1)) obtained with the two media were 3-4 times higher than that obtained with glucose medium (21.0 U mL(-1)).

    CONCLUSION This approach could contribute to economical conversion of cellulosic waste to two high value-added microbial products, while also providing new raw materials for a more sustainable textile industry. 

  • 4. Jogi, Ramakrishna
    et al.
    Mäki-Arvela, Päivi
    Virtanen, Pasi
    Kumar, Narendra
    Hemming, Jarl
    Smeds, Annika
    Lestander, Torbjörn A.
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Industrial Chemistry & Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Åbo-Turku, Finland.
    Biocrude production through hydro‐liquefaction of wood biomass in supercritical ethanol using iron silica and iron Beta zeolite catalysts2019Ingår i: Journal of chemical technology and biotechnology (1986), ISSN 0268-2575, E-ISSN 1097-4660, Vol. 94, nr 11, s. 3736-3744Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: In the production of biofuels from lignocellulosic material, biocrude plays a key role. The present work deals with the biocrude production through hydrothermal liquefaction (HTL) of birch wood in supercritical ethanol over 5 wt. % Fe‐H‐Beta‐150 (SiO2 to Al2O3 ratio of 150) or 5 wt. % Fe‐SiO2 catalyst.

    RESULTS: The liquid and solid products were characterized with various analytical techniques such as GC‐MS, GC‐FID, SEC, ICP‐MS, p‐XRD, SEM, and solid‐state 13C MAS NMR respectively. The results revealed that 5 wt. % Fe‐H‐Beta‐150, a strongly Brønsted acidic catalyst, enhanced the biocrude formation when compared with a non‐acidic 5 wt. % Fe‐SiO2 catalyst. Hemicellulose and lignin degradation occurred resulting in formation of mainly sugars, acids‐esters and phenolic compounds in liquid phase. The gaseous atmosphere of hydrogen also enhanced the degradation of biomass. The biocrude yield from birch was 25 wt. % over 5 wt. % Fe‐H‐Beta‐150. The Brønsted acidic catalyst gave higher dissolution efficiency and its clear catalytic effect was observed in comparison to non‐acidic 5 wt. % Fe‐SiO2. The degradation level of lignin in presence of 5 wt. % Fe‐H‐Beta‐150 was high 68 wt. % aromatic products were formed, while only 38 wt. % was obtained with 5 wt. % Fe‐SiO2.

    CONCLUSIONS: Hydrogen atmosphere enhances the fractionation of birch wood when compared to argon atmosphere. 5 wt. % Fe‐H‐Beta‐150 catalyst enhanced very strongly the degradation of hemicellulose and lignin in biomass to sugars and acid‐esters as well as phenolic compounds, respectively compared to the non‐acidic 5 wt. % Fe‐SiO2 catalyst.

  • 5. Jogunola, Olatunde
    et al.
    Salmi, Tapio
    Wärnå, Johan
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Kinetic studies of alkyl formate hydrolysis using formic acid as a catalyst2012Ingår i: Journal of chemical technology and biotechnology (1986), ISSN 0268-2575, E-ISSN 1097-4660, Vol. 87, nr 2, s. 286-293Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: The hydrolysis of methyl formate is the major industrial process forthe production of formic acid. The aim of the work is to determine the reaction kinetics quantitatively in the presence of formic acid catalyst, develop a mathematical model for the reaction system and estimate the kinetic parameters for the purpose of optimization.RESULTS: Liquid phase hydrolysis kinetics of alkyl formates (ethyl and methyl formate) was studied in an isothermal batch reactor at 80-110oC and 20 bar nitrogen pressure. The catalyst of choice was formic acid. The reaction rate was enhanced but the formic acid product yield was slightly suppressed relative to the uncatalysed system. A kinetic model comprising mass balances and rate equations was developed and the kinetic and equilibrium parameters included in the rate equations were estimated from the experimental data with non-linear regression analysis.CONCLUSION: The model was able to predict the experimental results successfully.Furthermore, the results obtained were compared quantitatively with an earlier model involving alkyl formate hydrolysis in a neutral aqueous solution.

  • 6. Sifontes Herrera, Víctor A
    et al.
    Oladele, Oluwamuyiwa
    Kordás, Krisztián
    Eränen, Kari
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Murzin, Dmitry Yu
    Salmi, Tapio
    Sugar hydrogenation over a Ru/C catalyst2011Ingår i: Journal of chemical technology and biotechnology (1986), ISSN 0268-2575, E-ISSN 1097-4660, Vol. 86, nr 5, s. 658-668Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: In recent years, exploitation of renewable resources has gained considerable attention. In this respect, polyols derived from the hydrogenation of sugar molecules are versatile molecules with a variety of uses, such as low-caloric sweeteners. The hydrogenation of D-maltose, D-galactose, L-rhamnose and L-arabinose was carried out on a finely dispersed Ru/activated carbon catalyst with the objective of studying the kinetics of the production of the corresponding polyols. The reactions were carried out in a stirred tank reactor at temperatures ranging from 90 to 130 °C and hydrogen pressures from 40 to 60 bar.

    RESULTS: Sugar conversions up to 100% were achieved. Some by-product formation affecting the quality of the selectivity was also observed at elevated operating conditions. The catalyst was characterized by scanning electron microcopy (SEM), transmission electron microscopy (TEM), inductively coupled plasma optical emission spectrometry (ICP-OES) and nitrogen physisorption. Kinetic models based on the Langmuir Hinshelwood assumptions were proposed for the reactions and a nonlinear regression was performed to obtain the numerical values of the kinetic parameters.

    CONCLUSIONS: The kinetic models predicted well the sugar hydrogenation process and the kinetic parameters were established. The model can be used to predict the behaviour of batchwise operating slurry reactors. Copyright © 2011 Society of Chemical Industry

  • 7.
    Soudham, Venkata Prabhakar
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Gräsvik, John
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Alriksson, Björn
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Laboratory of Industrial Chemistry and Reaction Engineering, Department of Chemical Engineering, Process Chemistry Centre, Åbo Akademi University, Åbo-Turku, Finland.
    Jönsson, Leif J
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Enzymatic hydrolysis of Norway spruce and sugarcane bagasse after treatment with 1-allyl-3-methylimidazolium formate2013Ingår i: Journal of chemical technology and biotechnology (1986), ISSN 0268-2575, E-ISSN 1097-4660, Vol. 88, nr 12, s. 2209-2215Artikel i tidskrift (Refereegranskat)
    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 72 h. After 12 h 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. © 2013 Society of Chemical Industry

  • 8.
    Winestrand, Sandra
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Gandla, Madhavi Latha
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Hong, Feng
    Chen, Qi Zhi
    Jönsson, Leif J
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Oxalate decarboxylase of Trametes versicolor: biochemical characterization and performance in bleaching filtrates from the pulp and paper industry2012Ingår i: Journal of chemical technology and biotechnology (1986), ISSN 0268-2575, E-ISSN 1097-4660, Vol. 87, nr 11, s. 1600-1606Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: Oxalate decarboxylase (ODC) from acid-induced cultures of the white-rot fungus Trametes versicolor was purified and characterized with respect to its biochemical properties and the possibility to utilize the enzyme for treatment of process water with the intention to prevent problems with calcium-oxalate scaling in the pulp and paper industry. RESULTS: Purified T. versicolor ODC was identified by tandem mass spectrometry. As estimated by using SDS-PAGE, the molecular mass was 69 kDa, and 60 kDa after deglycosylation with N-glycosidase F. The pH optimum was 2.5 and the temperature optimum was 4045 degrees C. The effects of ten potential inhibitors in industrial filtrates were examined. The enzyme was sensitive to low concentrations (0.1 mmol L-1) of chlorite and sulfite. T. versicolor ODC exhibited activity in 16 filtrates collected from mechanical pulping and kraft pulping. It had higher activity than ODC from Aspergillus niger in all of the filtrates and higher activity than oxalate oxidase from barley in all filtrates except two. CONCLUSIONS: The investigation shows basic biochemical properties of T. versicolor ODC and indicates that the enzyme may be useful for treatment of industrial filtrates under acidic conditions. Copyright (c) 2012 Society of Chemical Industry

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