| 1. |
- Alfredo Zambrano, José, et al.
(författare)
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Characterization of high Arabinoxylan oat lines identified from a mutagenized oat population
- 2023
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Ingår i: Food Chemistry. - : Elsevier BV. - 0308-8146. ; 404
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Tidskriftsartikel (refereegranskat)abstract
- Oat (Avena sativa) is a nutritionally important cereal crop that is rich in health-promoting dietary fibers, favorable proteins and polar lipids. In this work, ca. 500 random lines of a mutagenized oat population of high genetic variation were screened for arabinoxylan (AX) content. This identified lines with up to 60% higher AX levels in flour from whole seed and up to 100% higher in flour from dehulled seeds, as compared to the original Belinda variety. In addition, the cellular localization of AX was determined in cross-sections of dehulled seeds from three high and one low AX line using a xylan-specific antibody. This revealed variations in the amount and localization of AX between high and low AX lines. The high AX lines will now serve as a starting point in the development of oat varieties with superior health-promoting and rheological properties.
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| 2. |
- Allahgholi, Leila, et al.
(författare)
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Composition analysis and minimal treatments to solubilize polysaccharides from the brown seaweed Laminaria digitata for microbial growth of thermophiles
- 2020
-
Ingår i: Journal of Applied Phycology. - : Springer Science and Business Media LLC. - 0921-8971 .- 1573-5176. ; 32:3, s. 1933-1947
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Tidskriftsartikel (refereegranskat)abstract
- Brown macroalgae (Phaeophyta) hold high potential as feedstock for biorefineries due to high biomass productivity and carbohydrate content. They are, however, a challenging, unconventional feedstock for microbial refining and several processing problems need to be solved to make them a viable option. Pre-treatment is necessary to enhance accessibility and solubility of the biomass components but should be minimal and mild to assure sustainable and cost-effective processing. Here, two routes to pre-treatLaminaria digitata to release polysaccharides were investigated: hot water pre-treatment by autoclaving (121 °C, 20 min or 60 min) and a two-step extraction with mild acid (0.1 M HCl) followed by alkaline treatment. Hot water pre-treatment resulted in partial extraction of a mixture of polysaccharides consisting of alginate, fucoidan and laminarin. After mild acid pre-treatment, alginate was found in the remaining insoluble residues and was extracted in a second step via alkaline treatment using Na2CO3 (0.15 M) at 80 °C and CaCl2 (10%) for the precipitation. In addition to carbohydrates, a fraction of other components such as proteins, phenolic compounds, minerals and trace elements was detected in the extracts. Cultivation of the thermophilic bacterial strains Rhodothermus marinus DSM 16675 and Bacillus methanolicus MGA3 (ATCC 53907) in media supplemented with the respective extracts resulted in growth of both strains, indicating that they were able to utilize the available carbon source for growth. R. marinus displayed the highest cell density in the medium containing the extract from acid pre-treatment, whereas B. methanolicus growth was highest with the extract from hot water pre-treatment.
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| 3. |
- Daugbjerg Christensen, Monica, et al.
(författare)
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Cloning and Characterization of a Novel N-Acetyl-D-galactosamine-4-O-sulfate Sulfatase, SulA1, from a Marine Arthrobacter Strain
- 2024
-
Ingår i: Marine Drugs. - 1660-3397. ; 22:3
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Tidskriftsartikel (refereegranskat)abstract
- Sulfation is gaining increased interest due to the role of sulfate in the bioactivity of many polysaccharides of marine origin. Hence, sulfatases, enzymes that control the degree of sulfation, are being more extensively researched. In this work, a novel sulfatase (SulA1) encoded by the gene sulA1 was characterized. The sulA1-gene is located upstream of a chondroitin lyase encoding gene in the genome of the marine Arthrobacter strain (MAT3885). The sulfatase was produced in Escherichia coli. Based on the primary sequence, the enzyme is classified under sulfatase family 1 and the two catalytic residues typical of the sulfatase 1 family—Cys57 (post-translationally modified to formyl glycine for function) and His190—were conserved. The enzyme showed increased activity, but not improved stability, in the presence of Ca2+, and conserved residues for Ca2+ binding were identified (Asp17, Asp18, Asp277, and Asn278) in a structural model of the enzyme. The temperature and pH activity profiles (screened using p-nitrocatechol sulfate) were narrow, with an activity optimum at 40–50 °C and a pH optimum at pH 5.5. The Tm was significantly higher (67 °C) than the activity optimum. Desulfation activity was not detected on polymeric substrates, but was found on GalNAc4S, which is a sulfated monomer in the repeated disaccharide unit (GlcA–GalNAc4S) of, e.g., chondroitin sulfate A. The position of the sulA1 gene upstream of a chondroitin lyase gene and combined with the activity on GalNAc4S suggests that there is an involvement of the enzyme in the chondroitin-degrading cascade reaction, which specifically removes sulfate from monomeric GalNAc4S from chondroitin sulfate degradation products.
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| 4. |
- Dishisha, Tarek
(creator_code:cre_t)
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3-hydroxypropionaldehyde detection and extraction
- 2018
-
Patent (övrigt vetenskapligt/konstnärligt)abstract
- The present invention relates to a method of extg. 3-hydroxypropionaldehyde (3-HPA) and/or derivs. thereof from an aq. soln. comprising 3-HPA. This method comprises (a) contacting the aq. soln. comprising 3-HPA with chitosan and/or chitosan comprising polymers, (b) sepg. the 3-HPA bound chitosan and/or chitosan comprising polymers, and (c) washing the 3-HPA bound chitosan and/or chitosan comprising polymers at least once with a washing medium (wherein 3-HPA and/or derivs. thereof is in the washing medium).
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| 5. |
- Huang, Fang, et al.
(författare)
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Cultivation of the gut bacterium Prevotella copri DSM 18205T using glucose and xylose as carbon sources
- 2021
-
Ingår i: MicrobiologyOpen. - : Wiley. - 2045-8827. ; 10:3
-
Tidskriftsartikel (refereegranskat)abstract
- Prevotella copri DSM18205T is a human gut bacterium, suggested as a next-generation probiotic. To utilize it as such, it is, however, necessary to grow the species in a reproducible manner. Prevotella copri has previously been reported to be highly sensitive to oxygen, and hence difficult to isolate and cultivate. This study presents successful batch cultivation strategies for viable strain inoculations and growth in both serum bottles and a stirred tank bioreactor (STR), without the use of an anaerobic chamber, as long as the cells were kept in the exponential growth phase. A low headspace volume in the STR was important to reach high cell density. P. copri utilized xylose cultivated in Peptone Yeast Xylose medium (PYX medium), resulting in a comparable growth rate and metabolite production as in Peptone Yeast Glucose medium (PYG medium) in batch cultivations at pH 7.2.Up to 5 g/L of the carbon source was consumed, leading to the production of succinic acid, acetic acid, and formic acid, and cell densities (OD620 nm ) in the range 6-7.5. The highest yield of produced succinic acid was 0.63 ± 0.05 g/g glucose in PYG medium cultivations and 0.88 ± 0.06 g/g xylose in PYX medium cultivations.
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| 6. |
- Jönsson, Madeleine, et al.
(författare)
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Extraction and Modification of Macroalgal Polysaccharides for Current and Next-Generation Applications
- 2020
-
Ingår i: Molecules. - : MDPI AG. - 1420-3049. ; 25:930
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Tidskriftsartikel (refereegranskat)abstract
- Marine macroalgal (seaweed) polysaccharides are highly promising for next-generation applications in several industries. However, despite the reported comprehensive potential of these polysaccharides, commercial products are scarce on the market. Seaweed cultivations are increasing in number and production quantity, owing to an elevated global trend of utilization interest in seaweed. The extraction of polysaccharides from seaweed generally generates low yields, but novel methods are being developed to facilitate and improve the extraction processes. Current areas of applications for seaweed polysaccharides mainly take advantage of the physicochemical properties of certain polysaccharides, such as gelling, thickening and emulsifying. However, many of the numerous bioactivities reported are still only at research level and lack clinical evidence for commercialization. It has been suggested the construction of smaller units may generate better defined molecules that are more suitable for biomedical applications. Enzymatic modification is a promising tool for the generation of more defined, targeted biomolecules. This review covers; structural differences between the most predominant marine algal polysaccharides, extraction processes, modification alternatives, as well as a summary of current and potential next-generation application areas.
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| 7. |
- Khaleghipour, Leila, et al.
(författare)
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Extraction of sugarcane bagasse arabinoxylan, integrated with enzymatic production of xylo-oligosaccharides and separation of cellulose
- 2021
-
Ingår i: Biotechnology for Biofuels. - : Springer Science and Business Media LLC. - 1754-6834. ; 14:1
-
Tidskriftsartikel (refereegranskat)abstract
- Sugarcane processing roughly generates 54 million tonnes sugarcane bagasse (SCB)/year, making SCB an important material for upgrading to value-added molecules. In this study, an integrated scheme was developed for separating xylan, lignin and cellulose, followed by production of xylo-oligosaccharides (XOS) from SCB. Xylan extraction conditions were screened in: (1) single extractions in NaOH (0.25, 0.5, or 1 M), 121 °C (1 bar), 30 and 60 min; (2) 3 × repeated extraction cycles in NaOH (1 or 2 M), 121 °C (1 bar), 30 and 60 min or (3) pressurized liquid extractions (PLE), 100 bar, at low alkalinity (0-0.1 M NaOH) in the time and temperature range 10-30 min and 50-150 °C. Higher concentration of alkali (2 M NaOH) increased the xylan yield and resulted in higher apparent molecular weight of the xylan polymer (212 kDa using 1 and 2 M NaOH, vs 47 kDa using 0.5 M NaOH), but decreased the substituent sugar content. Repeated extraction at 2 M NaOH, 121 °C, 60 min solubilized both xylan (85.6% of the SCB xylan), and lignin (84.1% of the lignin), and left cellulose of high purity (95.8%) in the residuals. Solubilized xylan was separated from lignin by precipitation, and a polymer with β-1,4-linked xylose backbone substituted by arabinose and glucuronic acids was confirmed by FT-IR and monosaccharide analysis. XOS yield in subsequent hydrolysis by endo-xylanases (from glycoside hydrolase family 10 or 11) was dependent on extraction conditions, and was highest using xylan extracted by 0.5 M NaOH, (42.3%, using Xyn10A from Bacillus halodurans), with xylobiose and xylotriose as main products. The present study shows successful separation of SCB xylan, lignin, and cellulose. High concentration of alkali, resulted in xylan with lower degree of substitution (especially reduced arabinosylation), while high pressure (using PLE), released more lignin than xylan. Enzymatic hydrolysis was more efficient using xylan extracted at lower alkaline strength and less efficient using xylan obtained by PLE and 2 M NaOH, which may be a consequence of polymer aggregation, via remaining lignin interactions.
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| 8. |
- Linares-Pastén, Javier, et al.
(författare)
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Efficient poly(3-hydroxypropionate) production from glycerol using Lactobacillus reuteri and recombinant Escherichia coli harboring L. reuteri propionaldehyde dehydrogenase and Chromobacterium sp. PHA synthase genes.
- 2015
-
Ingår i: Bioresource Technology. - : Elsevier BV. - 1873-2976 .- 0960-8524. ; 180, s. 172-176
-
Tidskriftsartikel (refereegranskat)abstract
- Poly(3-hydroxypropionate), P(3HP), is a polymer combining good biodegradability with favorable material properties. In the present study, a production system for P(3HP) was designed, comprising conversion of glycerol to 3-hydroxypropionaldehyde (3HPA) as equilibrium mixture with 3HPA-hydrate and -dimer in aqueous system (reuterin) using resting cells of native Lactobacillus reuteri in a first stage followed by transformation of the 3HPA to P(3HP) using recombinant Escherichia coli strain co-expressing highly active coenzyme A-acylating propionaldehyde dehydrogenase (PduP) from L. reuteri and polyhydroxyalkanoate synthase (PhaCcs) from Chromobacterium sp. P(3HP) content of up to 40% (w/w) cell dry weight was reached, and the yield with respect to the reuterin consumed by the cells was 78%. Short biotransformation period (4.5h), lack of additives or expensive cofactors, and use of a cheap medium for cultivation of the recombinant strain, provides a new efficient and potentially economical system for P(3HP) production.
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| 9. |
- Majumdar, Abhinav, et al.
(författare)
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Macromolecular characterization of high β-glucan oat lines
- 2024
-
Ingår i: Heliyon. - 2405-8440. ; 10:2
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Tidskriftsartikel (refereegranskat)abstract
- Oat (Avena sativa) is a cereal grain rich in fibers, proteins, vitamins and minerals. Oats have been linked to several health benefits, such as lowering blood cholesterol levels, counteracting cardiovascular disease and regulating blood sugar levels. This study aimed to characterize two new oat lines with high β-glucan content emanating from ethyl methyl sulphonate mutagenesis on the Lantmännen elite variety Belinda. Two of the mutated lines, and the mother variety Belinda, were profiled for β-glucan, arabinoxylan, total dietary fiber and starch composition. In addition, total lipid and protein content, amino acid composition and β-glucan molecular weights were analyzed. The high levels of β-glucan resulted in a significant increase in total dietary fiber, but no correlation could be established between higher or lower levels of the assayed macromolecules, i.e., between arabinoxylan-, starch-, lipid- or protein levels in the mutated lines compared to the reference. The results indicate separate biosynthetic pathways for β-glucans and other macromolecules and an independent regulation of the different polysaccharides studied. Therefore, ethyl methyl sulphonate mutagenesis can be used to increase levels of multiple macromolecules in the same line.
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| 10. |
- Mukti, Israt Jahan, et al.
(författare)
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Medium development and production of carotenoids and exopolysaccharides by the extremophile Rhodothermus marinus DSM16675 in glucose-based defined media
- 2022
-
Ingår i: Microbial Cell Factories. - : Springer Science and Business Media LLC. - 1475-2859. ; 21
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The marine thermophilic bacterium Rhodothermus marinus can degrade many polysaccharides which makes it interesting as a future cell factory. Progress using this bacterium has, however, been hampered by limited knowledge on media and conditions for biomass production, often resulting in low cell yields and low productivity, highlighting the need to develop conditions that allow studies of the microbe on molecular level. This study presents development of defined conditions that support growth, combined with evaluation of production of carotenoids and exopolysaccharides (EPSs) by R. marinus strain DSM 16675.Results: Two defined media were initially prepared: one including a low addition of yeast extract (modified Wolfe’s medium) and one based on specific components (defined medium base, DMB) to which two amino acids (N and Q), were added. Cultivation trials of R. marinus DSM 16675 in shake flasks, resulted in maximum cell densities (OD620 nm) of 2.36 ± 0.057, cell dry weight (CDW) 1.2 ± 0.14 mg/L, total carotenoids 0.59 × 10–3 mg/L, and EPSs 1.72 ± 0.03 mg/L using 2 g/L glucose in DMB. In Wolfe’s medium (supplemented by 0.05 g/L yeast extract and 2.5 g/L glucose), maximum OD620 nm was 2.07 ± 0.05, CDW 1.05 ± 0.07 mg/L, total carotenoids 0.39 × 10–3 mg/L, and EPSs 1.74 ± 0.2 mg/L. Growth trials at 5 g/L glucose in these media either failed or resulted in incomplete substrate utilization. To improve reproducibility and increase substrate utilization, a screening of macroelements (e.g. phosphate) in DMB, was combined with use of trace elements and vitamins of the modified Wolfe’s medium. The resulting defined minimal R. marinus medium, (DRM), allowed reproducible cultivations to a final OD620nm of 6.6 ± 0.05, CDW 2.85 ± 0.07 mg/L, a maximum specific growth rate (µmax) of 0.26 h−1, total carotenoids 0.77 × 10–3 mg/L and EPSs 3.4 ± 0.17 mg/L in cultivations supplemented with up to 5 g/L glucose.Conclusion: A minimal defined medium (DRM) was designed that resulted in reproducible growth and an almost doubled formation of both total carotenoids and EPSs. Such defined conditions, are necessary for systematic studies of metabolic pathways, to determine the specific requirements for growth and fully characterize metabolite production.
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| 11. |
- Nordberg Karlsson, Eva, et al.
(författare)
-
Metabolic engineering of thermophilic bacteria for production of biotechnologically interesting compounds
- 2020
-
Ingår i: Biotechnological applications of extremophilic microorganisms. - : De Gruyter. - 9783110424331 ; , s. 73-96
-
Bokkapitel (refereegranskat)abstract
- Many thermophilic bacteria are efficient biomass degraders (producing polysaccharide degrading enzymes and utilizing a great variety of substrates, e.g. lignocellulosic polymers, pentoses, hexoses, as well sugar acids, and sugar alcohols). This makes them interesting organisms as potential cell factories in a circular bioeconomy. Lignocellulosic and marine macroalgal biomasses are regarded as sustainable biorefinery feedstocks for the production of energy carriers and platform and specialty chemicals, thereby meeting impending fossil fuel shortage and counteracting accumulation of greenhouse gasses. However, progress in using thermophilic bacteria that utilize these feedstocks as carbon sources has been hampered by the lack of suitable engineering tools to improve the production profiles of interesting target metabolites as specific synthetic production pathways need to be inserted/modified or existing pathways optimized by metabolic engineering. In this chapter, we review the progress on the use of thermophilic bacteria in metabolic engineering and the available engineering tools and give examples of species for which successful engineering has been accomplished. Today, the majority of thermophilic bacteria targeted for production of compounds of industrial interest by metabolic engineering belong to the phylum Firmicutes (e.g. Thermoanaerobacterium, Caldocellulosiruptor, Geobacillus, and Bacillus), taking advantage of anaerobic catabolic pathways producing organic acids and alcohols. However, there are additional and aerobic species gaining interest concerning biomass degradation and the ability of carbon dioxide fixation as well as production of molecules of interest, and some examples of this are also given.
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| 12. |
- Norlander, Siri, et al.
(författare)
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Effect of kilning on the macronutrient composition profile of three Swedish oat varieties
-
Ingår i: Cereal Chemistry. - 0009-0352.
-
Tidskriftsartikel (refereegranskat)abstract
- Background and ObjectivesKilning is crucial in oat processing, to prevent rancidity and extend shelf-life. This study examines kilning effects on the macronutrient composition in Swedish oat varieties Galant, Fatima, and Belinda. We compared two kilning methods: one mimicking industrial practice and a simplified version. We analyzed dietary fibers (arabinoxylan, β-glucan), protein and amino acids, lipid profile, lipase activity, and antioxidant capacity in these oat samples.FindingsDistinct compositional differences were found: Galant had low lipid content, Fatima had elevated lipid and protein levels with fewer carbohydrates, and Belinda was rich in β-glucan and dietary fibers. Both kilning procedures had similar impacts on all varieties, causing no major changes in dietary fiber or total protein content, but resulting in a 20% decrease in soluble proteins. Kilning decreased levels of several amino acids in Belinda, while the l-glutamate/glutamine ratio increased across all varieties. Lipid analysis showed minimal kilning-induced changes; yet, antioxidative capacity diminished. Both kilning methods effectively inactivated lipases.ConclusionsThese findings emphasize macronutrient variations among oat varieties and the effect of kilning on soluble proteins, amino acids, and antioxidative capacity.Significance and NoveltyThis study underscores the need for precise control in oat processing, crucial in plant-based protein and novel food development for optimal quality and yield.
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| 13. |
- Ron, Emanuel, et al.
(författare)
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Characterization of carotenoids in Rhodothermus marinus
- 2018
-
Ingår i: MicrobiologyOpen. - : Wiley. - 2045-8827. ; 7:1
-
Tidskriftsartikel (refereegranskat)abstract
- Rhodothermus marinus, a marine aerobic thermophile, was first isolated from an intertidal hot spring in Iceland. In recent years, the R. marinus strain PRI 493 has been genetically modified, which opens up possibilities for targeted metabolic engineering of the species, such as of the carotenoid biosynthetic pathway. In this study, the carotenoids of the R. marinus type-strain DSM 4252T, strain DSM 4253, and strain PRI 493 were characterized. Bioreactor cultivations were used for pressurized liquid extraction and analyzed by ultra-high performance supercritical fluid chromatography with diode array and quadropole time-of-flight mass spectrometry detection (UHPSFC-DAD-QTOF/MS). Salinixanthin, a carotenoid originally found in Salinibacter ruber and previously detected in strain DSM 4253, was identified in all three R. marinus strains, both in the hydroxylated and nonhydroxylated form. Furthermore, an additional and structurally distinct carotenoid was detected in the three strains. MS/MS fragmentation implied that the mass difference between salinixanthin and the novel carotenoid structure corresponded to the absence of a 4-keto group on the ß-ionone ring. The study confirmed the lack of carotenoids for the strain SB-71 (ΔtrpBΔpurAcrtBI’::trpB) in which genes encoding two enzymes of the proposed pathway are partially deleted. Moreover, antioxidant capacity was detected in extracts of all the examined R. marinus strains and found to be 2–4 times lower for the knock-out strain SB-71. A gene cluster with 11 genes in two operons in the R. marinusDSM 4252T genome was identified and analyzed, in which several genes were matched with carotenoid biosynthetic pathway genes in other organisms.
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| 14. |
- Ron, Emanuel Y C, et al.
(författare)
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Cultivation technology development of Rhodothermus marinus DSM 16675
- 2019
-
Ingår i: Extremophiles : life under extreme conditions. - : Springer Science and Business Media LLC. - 1433-4909. ; 23:6, s. 735-745
-
Tidskriftsartikel (refereegranskat)abstract
- This work presents an evaluation of batch, fed-batch, and sequential batch cultivation techniques for production of R. marinus DSM 16675 and its exopolysaccharides (EPSs) and carotenoids in a bioreactor, using lysogeny broth (LB) and marine broth (MB), respectively, in both cases supplemented with 10 g/L maltose. Batch cultivation using LB supplemented with maltose (LBmalt) resulted in higher cell density (OD620 = 6.6) than use of MBmalt (OD620 = 1.7). Sequential batch cultivation increased the cell density threefold (OD620 = 20) in LBmalt and eightfold (OD620 = 14) in MBmalt. In both single and sequential batches, the production of carotenoids and EPSs using LBmalt was detected in the exponential phase and stationary phase, respectively, while in MBmalt formation of both products was detectable in both the exponential and stationary phases of the culture. Heteropolymeric EPSs were produced with an overall volumetric productivity (QE) of 0.67 (mg/L h) in MBmalt and the polymer contained xylose. In LB, QE was lower (0.1 mg/L h) and xylose could not be detected in the composition of the produced EPSs. In conclusion, this study showed the importance of a process design and medium source for production of R. marinus DSM 16675 and its metabolites.
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| 15. |
- Sabet Azad, Ramin, et al.
(författare)
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Coenzyme A-acylating propionaldehyde dehydrogenase (PduP) from Lactobacillus reuteri: Kinetic characterization and molecular modeling.
- 2013
-
Ingår i: Enzyme and Microbial Technology. - : Elsevier BV. - 0141-0229. ; 53:4, s. 235-242
-
Tidskriftsartikel (refereegranskat)abstract
- 3-Hydroxypropionic acid (3-HP), an important C3 chemical for a bio-based industry, is natively produced by Lactobacillus reuteri from glycerol. Conversion of glycerol occurs via the intermediate 3-hydroxypropionaldehyde (3-HPA), followed by an ATP-producing pathway initiated by the CoA-acylating propionaldehyde dehydrogenase (PduP). The pduP gene of L. reuteri was cloned and expressed in Escherichia coli and the recombinant enzyme was purified to homogeneity for characterization of its activity and properties. Kinetic studies with propionaldehyde as substrate showed a maximum specific activity of 28.9U/mg, which is 80-fold higher than that reported previously. Maximum activity of 18U/mg was obtained at 3-HPA concentration of 7mM, above which substrate inhibition was observed. Substrate inhibition was also seen with coenzyme A at a concentration above 0.5mM and with NADP(+) above 9mM. A structure of PduP is proposed based on homology modeling. In silico docking of the co-factors coenzyme A and NAD(+), respectively, showed a common binding site consisting of amino acids Thr145, Ile275, Cys277 and Ser417, which through site-directed mutagenesis to alanine and kinetic studies, were confirmed as essential for the catalytic activity of PduP.
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| 16. |
- Sabet Azad, Ramin, et al.
(författare)
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Production of 3-hydroxypropionic acid from 3-hydroxypropionaldehyde by recombinant Escherichia coli co-expressing Lactobacillus reuteri propanediol utilization enzymes.
- 2015
-
Ingår i: Bioresource Technology. - : Elsevier BV. - 1873-2976 .- 0960-8524. ; 180, s. 214-221
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Tidskriftsartikel (refereegranskat)abstract
- 3-Hydroxypropionic acid (3-HP) is an important platform chemical for the biobased chemical industry. Lactobacillus reuteri produces 3-HP from glycerol via 3-hydroxypropionaldehyde (3-HPA) through a CoA-dependent propanediol utilization (Pdu) pathway. This study was performed to verify and evaluate the pathway comprising propionaldehyde dehydrogenase (PduP), phosphotransacylase (PduL), and propionate kinase (PduW) for formation of 3-HP from 3-HPA. The pathway was confirmed using recombinant Escherichia coli co-expressing PduP, PduL and PduW of L. reuteri DSM 20016 and mutants lacking expression of either enzyme. Growing and resting cells of the recombinant strain produced 3-HP with a yield of 0.3mol/mol and 1mol/mol, respectively, from 3-HPA. 3-HP was the sole product with resting cells, while growing cells produced 1,3-propanediol as co-product. 3-HP production from glycerol was achieved with a yield of 0.68mol/mol by feeding recombinant E. coli with 3-HPA produced by L. reuteri and recovered using bisulfite-functionalized resin.
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| 17. |
- Sajib, Mursalin, 1987, et al.
(författare)
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Valorization of Brewer's spent grain to prebiotic oligosaccharide: Production, xylanase catalyzed hydrolysis, in-vitro evaluation with probiotic strains and in a batch human fecal fermentation model
- 2018
-
Ingår i: Journal of Biotechnology. - : Elsevier BV. - 1873-4863 .- 0168-1656. ; 268, s. 61-70
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Tidskriftsartikel (refereegranskat)abstract
- Brewer's spent grain (BSG) accounts for around 85% of the solid by-products from beer production. BSG was first extracted to obtain water-soluble arabinoxylan (AX). Using subsequent alkali extraction (0.5 M KOH) it was possible to dissolve additional AX. In total, about 57% of the AX in BSG was extracted with the purity of 45–55%. After comparison of nine xylanases, Pentopan mono BG, a GH11 enzyme, was selected for hydrolysis of the extracts to oligosaccharides with minimal formation of monosaccharides. Growth of Bifidobacterium adolescentis (ATCC 15703) was promoted by the enzymatic hydrolysis to arabinoxylooligosaccharides, while Lactobacillus brevis (DSMZ 1264) utilized only unsubstituted xylooligosaccharides. Furthermore, utilization of the hydrolysates by human gut microbiota was also assessed in a batch human fecal fermentation model. Results revealed that the rates of fermentation of the BSG hydrolysates by human gut microbiota were similar to that of commercial prebiotic fructooligosaccharides, while inulin was fermented at a slower rate. In summary, a sustainable process to valorize BSG to functional food ingredients has been proposed.
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| 18. |
- Sardari, Roya, et al.
(författare)
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Biotransformation of glycerol to 3-hydroxypropionaldehyde: Improved production by in situ complexation with bisulfite in a fed-batch mode and separation on anion exchanger.
- 2013
-
Ingår i: Journal of Biotechnology. - : Elsevier BV. - 1873-4863 .- 0168-1656. ; 168:4, s. 534-542
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Tidskriftsartikel (refereegranskat)abstract
- 3-Hydroxypropionaldehyde (3HPA) is an important C3 chemical that can be produced from renewable glycerol by resting whole cells of Lactobacillus reuteri. However the process efficiency is limited due to substrate inhibition, product-mediated loss of enzyme activity and cell viability, and also formation of by-products. Complex formation of 3HPA with sodium bisulfite and subsequent binding to Amberlite IRA-400 was investigated as a means of in situ product recovery and for overcoming inhibition. The adsorption capacity and -isotherm of the resin were evaluated using the Langmuir model. The resin exhibited maximum capacity of 2.92mmol complex/g when equilibrated with 45mL solution containing an equilibrium mixture of 2.74mmol 3HPA-bisulfite complex and 2.01mmol free 3HPA. The dynamic binding capacity based on the breakthrough curve of 3HPA and its complex on passing a solution with 2.49mmol complex and 1.65mmol free 3HPA was 2.01mmol/g resin. The bound 3HPA was desorbed from the resin using 0.20M NaCl with a high purity as a mixture of complexed- and free 3HPA at a ratio of 0.77mol/mol. Fed-batch biotransformation of glycerol (818.85mmol) with in situ 3HPA complexation and separation on the bisulfite-functionalized resin resulted in an improved process with consumption of 481.36mmol glycerol yielding 325.54mmol 3HPA at a rate of 17.13mmol/h and a yield of 68 mol%. Also, the cell activity was maintained for at least 28h.
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| 19. |
- 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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| 20. |
- Sardari, Roya, et al.
(författare)
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Improved production of 3-Hydroxypropionaldehyde by complex formation with bisulfite during biotransformation of glycerol
- 2013
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Ingår i: Biotechnology and Bioengineering. - : Wiley. - 1097-0290 .- 0006-3592. ; 110:4, s. 1243-1248
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Tidskriftsartikel (refereegranskat)abstract
- 3-Hydroxypropionaldehyde (3HPA) is an important specialty chemical which can be produced from glycerol using resting cells of Lactobacillus reuteri. This biocatalytic route, however, suffers from substrate- and product-mediated loss of enzyme activity within 2 h of biotransformation. In order to overcome the inhibitory effects of 3HPA, complex formation with sodium bisulfite was investigated, optimized and applied for in situ capture of the aldehyde during biotransformation of glycerol in a fed-batch process. As a result, the activity of the cells was maintained for at least 18 h. The 3HPA produced per gram cell dry weight was increased 5.7 times compared to the batch production process, and 2.2 times compared to fed-batch process without in situ complex formation. This approach may have potential for production and in situ removal of 3HPA after further process development. Biotechnol. Bioeng. © 2012 Wiley Periodicals, Inc.
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| 21. |
- Sardari, Roya R R, et al.
(författare)
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Evaluation of the production of exopolysaccharides by two strains of the thermophilic bacterium Rhodothermus marinus
- 2017
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Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617. ; 156, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- The thermophile Rhodothermus marinus produces extracellular polysaccharides (EPSs) that forms a distinct cellular capsule. Here, the first data on EPS production in strains DSM4252(T) and MAT493 are reported and compared. Cultures of both strains, supplemented with either glucose, sucrose, lactose or maltose showed that the EPS were produced both in the exponential and stationary growth phase and that production in the exponential phase was boosted by maltose supplementation, while stationary phase production was boosted by lactose. The latter was higher, resulting in 8.8 (DSM4252(T)) and 13.7mg EPS/g cell dry weight (MAT493) in cultures in marine broth supplemented with 10g/L lactose. The EPSs were heteropolymeric with an average molecular weight of 8×10(4)Da and different monosaccharides, including arabinose and xylose. FT-IR spectroscopy revealed presence of hydroxyl, carboxyl, N-acetyl, amine, and sulfate ester groups, showing that R. marinus produces unusual sulfated EPS with high arabinose and xylose content.
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| 22. |
- Sardari, Roya R.R., et al.
(författare)
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HPAEC-PAD analysis for determination of the amino acid profiles in protein fractions from oat flour combined with correction of amino acid loss during hydrolysis
- 2023
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Ingår i: Journal of Cereal Science. - : Elsevier BV. - 0733-5210. ; 109
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Tidskriftsartikel (refereegranskat)abstract
- Current derivatization-dependent approaches for amino acid composition analysis of cereal proteins have significant variability due to lack of direct analysis opportunities and loss of amino acids during protein-hydrolysis. To tackle these drawbacks, a novel direct, derivatization-free approach was successfully introduced, using HPAEC-PAD, and applied for analysis of hydrolyzed defatted oat flour and extracted flour protein fractions. The approach ensured reliable detection of amino acids, including L-tryptophan, as well as oxidation products of L-cysteine and L-methionine. A time course study, analysed by nonlinear least-square regression to determine rates of hydrolysis and loss of each amino acid, allowed comparison of the original mass fraction (AA0) of the respective amino acid in the oat flour mixture with the mass fraction obtained after 24 h hydrolysis (AA24). The difference between (AA0) and (AA24) was less than 0.05%, except for L-arginine (0.61%), glycine (0.14%), L-isoleucine (0.27%), and L-tryptophan (0.17%). The (AA0)s obtained corresponded to literature-data, and fitted with the amino acid composition estimated from deduced proteins encoded in the oat genome, except for L-arginine (27%) and L-glutamic acid/L-glutamine (10%). The amino acid composition estimation from sequence data indirectly confirmed that the high presence of L-arginine observed was a result of co-elution with unknown flour components.
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| 23. |
- Sardari, Roya R. R., et al.
(författare)
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Identification of Phlorotannins in the Brown Algae, Saccharina latissima and Ascophyllum nodosum by Ultra-High-Performance Liquid Chromatography Coupled to High-Resolution Tandem Mass Spectrometry
- 2021
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Ingår i: Molecules (Basel, Switzerland). - : MDPI AG. - 1420-3049. ; 26:1
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Tidskriftsartikel (refereegranskat)abstract
- Phlorotannins are bioactive polyphenols in brown macroalgae that make these algae interesting as healthy food. Specific phlorotannins are, however, seldom identified, and extracts from different species are often only analysed for total phenolic content (TPC). In this study, our focus was to identify phlorotannin molecules from Saccharina latissima and Ascophyllum nodosum (a species rich in these compounds) using ultra-high-performance liquid chromatography coupled to high-resolution tandem mass spectrometry (UHPLC-HRMS2). Water and ethanol (30 and 80% v/v) were used at solid:liquid ratios, extraction times and temperatures, proposed to result in high TPC in extracts from other species. The S. latissima extracts, however, did not allow phlorotannin detection by either UHPLC-UV/Vis or UHPLC-HRMS2, despite a TPC response by the Folin-Ciocalteu assay, pinpointing a problem with interference by non-phenolic compounds. Purification by solid phase extraction (SPE) led to purer, more concentrated fractions and identification of four phlorotannin species in A. nodosum and one in S. latissima by UHPLC-HRMS2, using extracts in ethanol 80% v/v at a solid:liquid ratio of 1:10 for 20 h at 25 °C with an added 10 h at 65 °C incubation of remaining solids. The phlorotannin with the formula C12H10O7 (corresponding to bifuhalol) is the first identified in S. latissima.
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| 24. |
- Sardari, Roya R R, et al.
(författare)
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Marine Poly- and Oligosaccharides as Prebiotics
- 2018
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Ingår i: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 66:44, s. 11544-11549
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Tidskriftsartikel (refereegranskat)abstract
- The marine environment can increase the global production of biomass. Interest in marine macroalgae and microorganisms has increased tremendously as a result of international agendas and market trends promoting sustainability as well as healthy food. Macroalgae and marine microorganisms contain unique poly- and oligosaccharides with different substitutions, e.g., sulfation or carboxylation. There is great potential to find prebiotic compounds from these marine-derived saccharides. However, the exact composition and substituent distribution needed for the activity is to a large extent unexplored. In depth investigations of these compounds will provide us with novel insights on the specific structures required for the observed functions.
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