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Örnsköldsvik, Sweden

Cavka A.,Umea University | Martin C.,Umea University | Alriksson B.,SP Processum AB | Mortsell M.,SEKAB E Technology AB | Jonsson L.J.,Umea University
Bioresource Technology | Year: 2015

Conditioning with reducing agents allows alleviation of inhibition of biocatalytic processes by toxic by-products generated during biomass pretreatment, without necessitating the introduction of a separate process step. In this work, conditioning of steam-pretreated spruce with sodium sulfite made it possible to lower the yeast and enzyme dosages in simultaneous saccharification and fermentation (SSF) to 1. g/L and 5. FPU/g WIS, respectively. Techno-economic evaluation indicates that the cost of sodium sulfite can be offset by benefits resulting from a reduction of either the yeast load by 0.68. g/L or the enzyme load by 1. FPU/g WIS. As those thresholds were surpassed, inclusion of conditioning can be justified. Another potential benefit results from shortening the SSF time, which would allow reducing the bioreactor volume and result in capital savings. Sodium sulfite conditioning emerges as an opportunity to lower the financial uncertainty and compensate the overall investment risk for commercializing a softwood-to-ethanol process. © 2015 The Authors.

Wiman M.,Lund University | Dienes D.,Lund University | Hansen M.A.T.,Copenhagen University | Van Der Meulen T.,SEKAB E Technology AB | And 2 more authors.
Bioresource Technology | Year: 2012

Spruce chips steam-pretreated at various conditions, according to a central composite design, were used for investigating the influence of pretreatment conditions on enzymatic hydrolysis, accounting for the individual effects of pretreatment temperature (194-220 °C), time (3-11 min) and sulfur dioxide uptake (0.7-2.5%). The materials were analyzed for several surface characteristics, including IR absorption, enzyme adsorption capacity, total surface area, cellulosic surface area, and cellulosic pore sizes. This work showed a clear correlation between rate of enzymatic hydrolysis and specific surface area. Although the lignin content of the particle surface increased at higher pretreatment temperature and residence time, the initial rate of enzymatic hydrolysis increased. Enzyme adsorption measurements and staining methods revealed that the higher rate of hydrolysis of these materials was due to increased accessibility of the cellulose. An accessible cellulose fraction is thus more important than a low surface lignin content for the enzymatic hydrolysis of steam-pretreated spruce. © 2011 Elsevier Ltd. All rights reserved.

Palmqvist B.,Lund University | Palmqvist B.,Novozymes AS | Kadic A.,Lund University | Hagglund K.,SEKAB E Technology AB | And 2 more authors.
Biomass Conversion and Biorefinery | Year: 2016

The importance of flow conditions during scale-up of high-solid enzymatic hydrolysis of steam-pretreated spruce was demonstrated by comparing hydrolysis rates between laboratory (2 L) and demonstration (4 m3) scale. A positive effect of increased agitation speed on the rate of enzymatic hydrolysis was found regardless of scale. Importantly, the hydrolysis rate was higher at the larger scale when compared at similar specific power inputs. Changes in the rheological properties of the pretreated material during the hydrolysis were followed by off-line measurements of apparent viscosity. This information was used to estimate the flow conditions in the reactors, i.e., average Reynolds numbers, which together with measured mixing power consumptions enabled a more detailed comparison between the scales. The hydrolysis yields correlated better with average Reynolds numbers than specific power input over the different scales. This indicates that mass transport limitations, caused by insufficient bulk flow, likely play a decisive role in determining the rate of enzymatic hydrolysis. © 2015, Springer-Verlag Berlin Heidelberg.

There is provided a method of producing a hydrolysate containing sugar from a lingocellulosic biomass, comprising the steps of: a) pretreating the lingocellulosic biomass in a pretreatment process to form a slurry comprising cellulosic particles; b) saccharification of the slurry obtained in step a) in the presence of hydrolytic enzymes in an enzymatic hydrolysis process to obtain a hydrolysate containing sugar; c) analyzing cellulosic particles present in the slurry obtained in step a) and/or cellulosic particles present in the enzymatic hydrolysis process during step b) using an image analysis method to obtain a data set; and d) controlling at least one process parameter of the pretreatment process in step a) and/or enzymatic hydrolysis process in step b) in response to the data set obtained in step c). A corresponding system is also provided.

The present invention relates to a method of enzymatic hydrolysis of a lignocellulosic material, comprising the steps of: a) pretreating the lignocellulosic material to obtain a slurry having a pH of less than 6; b) adding NaOH, Ca(OH)

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