Toward Green Production of Chewing Gum and Diet: Complete Hydrogenation of Xylose to Xylitol over Ruthenium Composite Catalysts under Mild Conditions

Liu, Caijuan; Zhu, Ning; Ma, Jian‐Gong; Cheng, Peng

doi:10.34133/2019/5178573

Cited by 9 publications

(10 citation statements)

References 59 publications

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“…Biosynthetic production of xylitol has the potential to decrease costs, while avoiding the use of organic solvents and eliminating the need for expensive reduction catalysts. 9 Most previous studies producing xylitol from xylose rely on a bioconversion requiring an additional sugar (usually glucose) as an electron donor. 3,10,11 Oxidation of glucose (producing the byproduct gluconic acid) generates NADPH which is then used for xylose reduction.…”

Section: Introductionmentioning

confidence: 99%

Dynamic control over feedback regulatory mechanisms improves NADPH fluxes and xylitol biosynthesis in engineeredE. coli

Moreb

et al. 2020

Preprint

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We report improved NADPH flux and xylitol biosynthesis in engineered E. coli. Xylitol is produced from xylose via an NADPH dependent reductase. We utilize two-stage dynamic metabolic control to compare two approaches to optimize xylitol biosynthesis, a stoichiometric approach, wherein competitive fluxes are decreased, and a regulatory approach wherein the levels of key regulatory metabolites are reduced. The stoichiometric and regulatory approaches lead to a 16 fold and 100 fold improvement in xylitol production, respectively. Strains with reduced levels of enoyl-ACP reductase and glucose-6-phosphate dehydrogenase, led to altered metabolite pools resulting in the activation of the membrane bound transhydrogenase and a new NADPH generation pathway, namely pyruvate ferredoxin oxidoreductase coupled with NADPH dependent ferredoxin reductase, leading to increased NADPH fluxes, despite a reduction in NADPH pools. These strains produced titers of 200 g/L of xylitol from xylose at 86% of theoretical yield in instrumented bioreactors. We expect dynamic control over enoyl-ACP reductase and glucose-6-phosphate dehydrogenase to broadly enable improved NADPH dependent bioconversions.HighlightsDecreases in NADPH pools lead to increased NADPH fluxesPyruvate ferredoxin oxidoreductase coupled with NADPH-ferredoxin reductase improves NADPH production in vivo.Dynamic reduction in acyl-ACP/CoA pools alleviate inhibition of membrane bound transhydrogenase and improve NADPH fluxXylitol titers > 200g/L in fed batch fermentations with xylose as a sole feedstock.

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Section: Introductionmentioning

confidence: 99%

Dynamic control over feedback regulatory mechanisms improves NADPH fluxes and xylitol biosynthesis in engineeredE. coli

Moreb

et al. 2020

Preprint

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“…In addition, 50 xylose % methanol was used to enhance hydrogen supply and the substrate was limited to a low level of 30 g/L. 37 In our study, at the same condition of 50 °C and 1 atm H 2 , without the addition of methanol, higher concentration of 100 g/L xylose was completely converted to xylitol within 60 h of reaction. The catalyst consumption was 0.025 g Ru/ MWCNTs/g xylose or 0.00115 g Ru/g xylose, which was much lower than the previous report 37 but fivefold higher than the reaction in our study at the reaction condition of 100 °C and under 3 MPa H 2 .…”

Section: Discussionmentioning

confidence: 59%

“…However, the very high catalyst consuming of 0.67 g of Ru@ZIF-67/g xylose or 0.079 g Ru /g xylose largely restricted the reaction cost. In addition, 50 xylose % methanol was used to enhance hydrogen supply and the substrate was limited to a low level of 30 g/L . In our study, at the same condition of 50 ° C and 1 atm H 2 , without the addition of methanol, higher concentration of 100 g/L xylose was completely converted to xylitol within 60 h of reaction.…”

Section: Discussionmentioning

confidence: 64%

Efficient Synthesis of Sugar Alcohols under Mild Conditions Using a Novel Sugar-Selective Hydrogenation Catalyst Based on Ruthenium Valence Regulation

Zhang

Wang

et al. 2020

J. Agric. Food Chem.

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Sugar alcohols are the prominent alternatives of sugars in food, medical, and health industries. The ruthenium supported on multiwalled carbon nanotubes (Ru/MWCNTs) catalysts were prepared based on the Ru valence regulation strategy and applied for selective sugar hydrogenation to prepare various sugar alcohols including xylitol, arabinitol, sorbitol, mannitol, and galactitol for the first time, with high selectivity (>99.0%) and yield (>98.0%) under mild conditions (≤110 °C, 3.0 MPa H2 pressure). The hydrogenation reaction of xylose was further optimized and under mild conditions (100 °C, 3.0 MPa H2 pressure, and 500 rpm), which were lower than ever reported for high efficient synthesis of xylitol, 99.8% xylose conversion and 99.0% xylitol yield were achieved after 120 min of reaction.

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“…1 , 10 , 13 The naturally occurring d -xylose, also known as wood sugar, is used as a sweetener and in the production of xylitol, which is commonly found in sugar-free chewing gum. 14 − 16 …”

Section: Introductionmentioning

confidence: 99%

Crystallization Behavior and Crystallographic Properties ofdl-Arabinose anddl-Xylose Diastereomer Sugars

Tyson

Pask

George

et al. 2022

Crystal Growth & Design

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Natural sugar molecules such as xylose and arabinose exhibit sweetness profiles similar to sucrose, which makes them a valuable alternative in low-calorie foods as well as excipients or cocrystallization agents in pharmaceutical formulations. Xylose and arabinose are also chiral diastereomers that can exhibit specific crystallization behavior. In this work, the solid-state landscapes of the chiral pairs of both xylose and arabinose have been investigated to determine whether racemic compounds or conglomerates are formed. Furthermore, single crystals of xylose and arabinose have been grown and characterized by X-ray diffraction and optical microscopy to study their crystallographic properties and relate them to the crystallization behavior. Differential scanning calorimetry (DSC) measurements were used to determine the phase diagrams of the two analyzed chiral systems. The solubilities of the different solid forms of xylose and arabinose were measured in different solvent mixtures by a thermogravimetric method. An analysis was conducted to assess the main thermodynamic parameters and the activity coefficients of the compounds in solution. Finally, slurry experiments in a 50:50 w/w ethanol/water solvent have also been performed to determine the relative stability of each solid form and the kinetics of transformation in this solvent mixture. It was found that dl -arabinose crystallizes as a stable racemic compound, which transforms quickly from its constituent enantiomers when in solution; whereas d - and l -xylose molecules crystallize separately as a conglomerate.

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Toward Green Production of Chewing Gum and Diet: Complete Hydrogenation of Xylose to Xylitol over Ruthenium Composite Catalysts under Mild Conditions

Cited by 9 publications

References 59 publications

Dynamic control over feedback regulatory mechanisms improves NADPH fluxes and xylitol biosynthesis in engineeredE. coli

Dynamic control over feedback regulatory mechanisms improves NADPH fluxes and xylitol biosynthesis in engineeredE. coli

Efficient Synthesis of Sugar Alcohols under Mild Conditions Using a Novel Sugar-Selective Hydrogenation Catalyst Based on Ruthenium Valence Regulation

Crystallization Behavior and Crystallographic Properties ofdl-Arabinose anddl-Xylose Diastereomer Sugars

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