| 1. |
- Faryar, Reza, et al.
(författare)
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Production of prebiotic xylooligosaccharides from alkaline extracted wheat straw using the K80R-variant of a thermostable alkali-tolerant xylanase
- 2015
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Ingår i: Food and Bioproducts Processing. - : Elsevier BV. - 1744-3571 .- 0960-3085. ; 93:Online 22 November 2014, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- Agricultural by-products are raw materials of importance for increased utilization of renewable biomass. Wheat straw is a raw material of significant production volume and is in this work used for production of xylooligosaccharides (XOS). Extraction of xylan by dilute alkali was followed by hydrolysis using a variant of the alkali-tolerant Bacillus halodurans S7 endoxylanase A mutated at K80R. The xylan yield was on average 56.5 g xylose equivalents per kg dried, ground wheat straw, with 1 arabinose per 12 xylose residues. The K80R variant, which displayed higher specific activity than the wild-type enzyme, was added at a load of 96 U/g extracted xylan. The XOS-yield (xylobiose – xylopentaose) was evaluated at time intervals in the temperature range of 50 to 65 degrees C, at pHs from 7 to 10. The enzyme was optimally active at 60 degrees C up to pH 9. Hydrolysis was completed within 7 h, resulting in 36 % conversion of the xylan to predominantly xylobiose. Xylose content was low (2.4%) despite extended incubation, which is desirable for XOS-production. The XOS-containing hydrolysate was confirmed as a suitable carbon source for the putative probiotic strain Lactobacillus brevis DSM 1269, showing the applicability of the method to obtain prebiotic XOS.
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| 2. |
- Mamo, Gashaw, et al.
(författare)
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Microbial glycoside hydrolases for biomass utilization in biofuels application
- 2013
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Ingår i: Biofuel Technologies: Recent Developments. - 9783642345180 ; , s. 171-188
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Bokkapitel (refereegranskat)abstract
- Renewable biomass is predicted to have the potential to meet at least a quarter of the world demand for transportation fuel, but to do so both terrestrial lignocellulosic as well as marine algal resources need to be efficiently utilized. In the processes where these biomasses are converted to different types of energy-carriers (for example fuel alcohols e.g. ethanol or butanol) microbial glycoside hydrolases have a role in the saccharification process. During saccharification polymeric carbohydrate resources (e.g. starch, cellulose or hemicellulose) are hydrolysed into mono and oligosaccharides that can be utilized by the organism selected to ferment these carbohydrates into the desired energy-carrier. This chapter aims to shed light on different processing alternatives for the conversion of lignocellulose or algal starch into mono or oligosaccharides, and what roles the microbial glycoside hydrolases have as processing aids in these conversions.
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| 3. |
- Mamo, Gashaw, et al.
(författare)
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Microbial glycoside hydrolases for biomass utilization in biofuels applications
- 2014
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Ingår i: Biofuel Technologies : Recent Developments - Recent Developments. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 3642345182 - 9783642345180 - 9783642345197 ; , s. 171-188
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Bokkapitel (refereegranskat)abstract
- Renewable biomass is predicted to have the potential to meet at least a quarter of the world demand for transportation fuel, but to do so both terrestrial lignocellulosic as well as marine algal resources need to be efficiently utilized. In the processes where these biomasses are converted into different types of energy carriers (for example fuel-alcohols e.g. ethanol or butanol) microbial glycoside hydrolases (GHs) have a role in the saccharification process. During saccharification polymeric carbohydrate resources (e.g. starch, cellulose or hemicellulose) are hydrolyzed into mono and oligosaccharides that can be utilized by the organism selected to ferment these carbohydrates into the desired energy-carrier. This chapter aims to shed light on different processing alternatives for the conversion of lignocellulose or algal starch into mono or oligosaccharides, and what roles the microbial GHs have as processing aids in these conversions.
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| 4. |
- Turner, Pernilla, et al.
(författare)
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Potential and utilization of thermophiles and thermostable enzymes in biorefining
- 2007
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Ingår i: Microbial Cell Factories. - : Springer Science and Business Media LLC. - 1475-2859. ; 6
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Forskningsöversikt (refereegranskat)abstract
- In today's world, there is an increasing trend towards the use of renewable, cheap and readily available biomass in the production of a wide variety of fine and bulk chemicals in different biorefineries. Biorefineries utilize the activities of microbial cells and their enzymes to convert biomass into target products. Many of these processes require enzymes which are operationally stable at high temperature thus allowing e. g. easy mixing, better substrate solubility, high mass transfer rate, and lowered risk of contamination. Thermophiles have often been proposed as sources of industrially relevant thermostable enzymes. Here we discuss existing and potential applications of thermophiles and thermostable enzymes with focus on conversion of carbohydrate containing raw materials. Their importance in biorefineries is explained using examples of lignocellulose and starch conversions to desired products. Strategies that enhance thermostablity of enzymes both in vivo and in vitro are also assessed. Moreover, this review deals with efforts made on developing vectors for expressing recombinant enzymes in thermophilic hosts.
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