| 1. |
- Sardari, Roya, et al.
(författare)
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Evaluation of sequential processing for the extraction of lipids, starch and proteins from wheat bran
- 2019
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Ingår i: Frontiers in Bioengineering and Biotechnology. - : Frontiers Media SA. - 2296-4185. ; 7:413
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Tidskriftsartikel (refereegranskat)abstract
- In line with the need to better utilize agricultural resources, and valorize underutilized fractions, we have developed protocols to increase the use of wheat bran, to improve utilization of this resource to additional products. Here, we report sequential processing for extraction of starch, lipids, and proteins from wheat brans with two different particle sizes leaving a rest-material enriched in dietary fiber. Mild water-based extraction of starch resulted in maximum 81.7 ± 0.67% yield. Supercritical fluid extraction of lipids by CO2 resulted in 55.2 ± 2.4% yield. This was lower than the corresponding yield using Soxhlet extraction, which was used as a reference method, but allowed a continued extraction sequence without denaturation of the proteins remaining in the raw-material. Alkaline extraction of non-degraded proteins resulted in a yield corresponding to one third of the total protein in the material, which was improved to reach 62 ± 8% by a combination of wheat bran enzymes activation followed by Osborne fractionation. The remaining proteins were extracted in degraded form, resulting in maximum 91.6 ± 1.6% yield of the total proteins content. The remaining material in both fine and coarse bran had a fiber content that on average corresponded to 73 ± 3%. The current work allows separation of several compounds, which is enabling valorization of the bran raw-material into several products.
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| 2. |
- Al-Rudainy, Basel, et al.
(författare)
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Antisolvent precipitation of hemicelluloses, lignosulfonates and their complexes from ultrafiltrated spent sulfite liquor (SSL)
- 2018
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Ingår i: Holzforschung. - : Walter de Gruyter GmbH. - 1437-434X .- 0018-3830. ; 72:10, s. 839-850
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Tidskriftsartikel (refereegranskat)abstract
- The possibility of precipitating high molecular weight (MW) softwood hemicelluloses has been investigated. Solids were precipitated from a sodium-based spent sulfite liquor with the anti-solvents acetone, ethanol and methanol and the effects of solute concentration, pH and temperature on the precipitation were studied. The product yield, degree of separation, MW and structure of the different fractions were determined using gravimetric analysis, high performance liquid chromatography (HPLC), ultraviolet–visible (UV-Vis) spectroscopy, size exclusion chromatography (SEC), and two-dimensional nuclear magnetic resonance (2D NMR). A direct correlation was found between the dielectric constant (also called relative permittivity) of the bulk solution and the yield of precipitants, based on which the separation of the solutes was predictable. The highest yield and degree of separation observed was an intercept around 76% with 47.5% acetone, which was the most efficient anti-solvent.
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| 3. |
- Al-Rudainy, Basel, et al.
(författare)
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From lab-scale to on-site pilot trials for the recovery of hemicellulose by ultrafiltration: Experimental and theoretical evaluations
- 2020
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Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1873-3794 .- 1383-5866. ; 250
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Tidskriftsartikel (refereegranskat)abstract
- Spent sulfite liquor (SSL) is a byproduct of the sulfite pulping process of wood. SSL usually contains monosugars and lignosulfonates, which are fermented to produce ethanol and dried to generate lignosulfonate salts. However, the SSL that was used in this work was derived from the first step of a 2-step sulfite pulping process of softwood under mild pulping conditions in the first stage of cooking. The resulting SSL contained polymeric hemicelluloses, which are not used today but have many potential applications. The up-concentration of this SSL had been performed on a lab scale by ultrafiltration. However, the pilot-scale ultrafiltration of hemicellulose-rich sodium-based SSL has not been reported. In this study, the operating conditions for the lab-scale concentration of hemicellulose-rich, sodium-based SSL were examined in a pilot-scale membrane filtration unit. The permeate flux and retention of products were lower in the pilot equipment compared with the lab-scale setup, perhaps related to the lower Reynolds number and shear rate in the former, as indicated by simulations of computational fluid dynamics. The pilot equipment also ran at a higher volume reduction compared with the lab-scale system, which could explain the difference in flux and retention. The effects of fouling and cleaning were also determined, wherein an alkaline cleaning step (pH 11) for 1 h was sufficient to remove foulants and maintain a stable average flux of 88 L/m2h and the nonchanging retention of products.
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| 4. |
- Al-Rudainy, Basel, et al.
(författare)
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From waste to high-value products: Impact of galactoglucomannan purity on selected hydrogel properties
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Hydrogels are a hydrophilic network of polymers (usually cross-linked polysaccharides) that are natural or synthetic. Applications of hydrogels are many in the biomedical field. Because of the high water absorption (10 to 200 grams of water per gram of hydrogel), hydrogels have a high degree of flexibility similar to natural human tissue. Human cells can be incorporated into the hydrogel, which in turn can be used to repair damaged tissue. An option is to incorporate drugs in the gels to treat a damaged area by a sustained-release drug-delivery system. Other uses have been in the production of bio-sensors, as absorbent in, e.g. diapers or in the production of contact lenses.Hemicelluloses (in this work galactoglucomannan (GGM)) are a promising renewable raw material for the production of hydrogels. Given their high abundance (constituting up to 25% of the wood cell walls) and current lack of use (usually incinerated together with other biopolymers in the pulp and paper industry), makes this work valuable from an economical and industrial point-of-view.In this work, we examine the possibility to produce hydrogels from GGM extracted from sodium-based spent-sulfite-liquor using a combination of membrane filtration and anti-solvent precipitation. The impact of GGM purity or the addition of lignosulfonates to the cross-linking reaction mixture (in-direct effect of the downstream processing, which affect the overall process economy) on the mechanical, thermal and chemical properties of the hydrogel have been examined and evaluated.
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| 5. |
- Al-Rudainy, Basel, et al.
(författare)
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Galactoglucomannan Recovery with Hydrophilic and Hydrophobic Membranes: Process Performance and Cost Estimations
- 2019
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Ingår i: Membranes. - : MDPI AG. - 2077-0375. ; 9:8
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we compared the GR51PP (hydrophobic/polysulfone) membrane with a series of hydrophilic (regenerated cellulose) membranes with the aim of increasing the retention of products and decreasing membrane fouling. The raw material used was a sodium-based spent sulfite liquor from the sulfite pulping process of spruce and pine. The results show that the hydrophilic membranes were superior to the hydrophobic membranes in terms of higher fluxes (up to twice the magnitude), higher product retentions and less fouling (up to five times lower fouling). The fouling was probably caused by pore blocking as observed in earlier studies. However, the hydrophilic membranes had a lower affinity for lignin, which was indicated by the lower retention and fouling. This also resulted in a separation degree, which was higher compared with the hydrophobic membrane, thus yielding a higher galactoglucomannan (GGM) purity. 2D HSQC NMR results show that no major structural differences were present in the hydrophilic and hydrophobic retentates. A techno-economical evaluation resulted in the RC70PP being chosen as the most cost-efficient membrane in terms of flux and product recovery.
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| 6. |
- Al-Rudainy, Basel, et al.
(författare)
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Hemicellulose Recovery from Spent-Sulfite-Liquor: Lignin Removal by Adsorption to Resins for Improvement of the Ultrafiltration Process
- 2020
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Ingår i: Molecules. - : MDPI AG. - 1420-3049. ; 25:15
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Tidskriftsartikel (refereegranskat)abstract
- In this work, three polymeric resins were examined as alternatives for the separation of hemicellulose and lignin. The aim was to remove the lignin from spent-sulfite-liquor (SSL) prior to ultrafiltration, producing a hemicellulose-rich retentate with high purity, and increase the capacity of the membrane filtration. The lignin in the SSL was sulfonated; thus, two of the resins were anion exchangers and 1 was hydrophobic. The data from the equilibrium studies and adsorption kinetics were fitted to established models, and the results were interpreted based on these observations. The strongly basic anion exchanger performed best with regard to lignin removal. The adsorption followed the Sips isotherm, indicating that the process was cooperative with chemisorption as the main reaction between the adsorbate and adsorbent based on the kinetics. Regeneration of the adsorbent was also possible, wherein 100 g/L NaCl was sufficient to recover 98% of the lignin. The lignin removal had a positive effect on the ultrafiltration process, in which the flux increased by 38% and the extent of separation between the hemicellulose and lignin rose from 17% to 59%.
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| 7. |
- Al-Rudainy, Basel, et al.
(författare)
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Impact of lignin content on the properties of hemicellulose hydrogels
- 2019
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Ingår i: Polymers. - : MDPI AG. - 2073-4360. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Hemicellulose is a promising renewable raw material for the production of hydrogels. This polysaccharide exists in large amounts in various waste streams, in which they are usually impure and heavily diluted. Several downstream processing methods can be combined to concentrate and purify the hemicellulose. However, such an approach can be costly; hence, the effect of impurities on the formation and properties of hydrogels must be determined. Lignin usually exists in these waste streams as a major impurity that is also difficult to separate. This compound can darken hydrogels and decrease their swellability and reactivity, as shown in many studies. Other properties and effects of lignin impurities are equally important for the end application of hydrogels and the overall process economy. In this work, we examined the feasibility of producing hydrogels from hemicelluloses that originated from sodium-based spent sulfite liquor. A combination of membrane filtration and anti-solvent precipitation was used to extract and purify various components. The influence of the purity of hemicellulose and the addition of lignosulfonates (emulated impurities in the downstream processing) to the crosslinking reaction mixture on the mechanical, thermal, and chemical properties of hydrogels was determined.
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| 8. |
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| 9. |
- Al-Rudainy, Basel, et al.
(författare)
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Influence of prefiltration on membrane performance during isolation of lignin-carbohydrate complexes from spent sulfite liquor
- 2017
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Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1383-5866. ; 187, s. 380-388
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we examined the isolation of lignin-carbohydrate complexes (LCCs) from sodium-based spent sulfite liquor, in conjunction with minimization of membrane fouling. We screened 3 polysulfone (PS) membranes with cutoffs of 100, 50, and 25 kDa, respectively. Flux and retention for the 100- and 50-kDa membranes had the same order of magnitude, indicating that these properties were determined by fouling that formed on the membrane—not pore size. The PS membrane with the 50-kDa cutoff performed best in terms of flux and retention of lignin-carbohydrate complexes and experienced the least membrane fouling. Two prefiltration methods were used to decrease the fouling of the 50-kDa membrane: a 0.2-μm PS microfiltration membrane and dead-end filtration with 10-um filter cloth and a 4 wt% mixture of kieselguhr (diatomite) and spent sulfite liquor prior to filtration. Prefiltration of the SSL with microfiltration increased the flux 3-fold and decreased the fouling grade from 49% to 7.2%. Dead-end filtration effected a 16% increase in flux and a fouling grade of 17%. The retention of LCC during microfiltration was high, which resulted in a loss of high-molecular-weight products, whereas the loss of LCC during dead-end filtration was negligible. A 50-kDa PS membrane performed best with regard to the recovery of lignin-carbohydrate complexes from spent sulfite liquor. Also, dead-end filtration is a promising method for eliminating membrane fouling.
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| 10. |
- Al-Rudainy, Basel, et al.
(författare)
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Techno-economic evaluation for the process optimization of galactoglucomannan and lignin recovery by ultrafiltration
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Galactoglucomannans (GGM) can be used as a precursor for the production of surfactants, plastics, hydrogels etc. However, separation of galactoglucomannan (GGM) from lignin and lignin-carbohydrate-complexes using membrane filtration is difficult. Precipitation of GGM with anti-solvents is an approach that has been previously studied. A membrane filtration step prior to precipitation is economically beneficial to decrease anti-solvent requirements with increasing concentration of GGM. However, previous studies have shown that membrane fouling is a problem that can have a large impact on the life-time of the membranes but also the overall yield of the products.The raw material used in this study was a sodium-based spent-sulfite-liquor (SSL) provided by Domsjö Fabriker (Örnsköldsvik, Sweden) and is the outtake after the first pulping step of softwood (60 % Picea abies and 40 % Pinus sylvestris). The SSL was concentrated with a 50 kDa polysulfone membrane (hydrophobic) and four regenerative cellulose membranes (30, 20, 10 and 5 kDa) (hydrophilic) to a volume reduction of 90 %. The resulting retentate was analyzed for the composition and the product yields were calculated. Membrane data, such as, flux, trans-membrane pressure, cross-flow velocity and degree of fouling were used together with the GGM yields in a techno-economic evaluation to find a cost-efficient process for the separation and purification of GGM and lignin from SSL.
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