26345-59-5Relevant articles and documents
Integration of Enzymatic and Heterogeneous Catalysis for One-Pot Production of Fructose from Glucose
Sun, Jiankui,Li, Helong,Huang, Hongzhi,Wang, Bo,Xiao, Ling-Ping,Song, Guoyong
, p. 1157 - 1162 (2018/03/21)
The search for efficient routes for the production of fructose from biomass-derived glucose is of great interest and importance, as fructose is a highly attractive substrate in the conversion of cellulosic biomass into biofuels and chemicals. In this study, a one-pot, multistep procedure involving enzyme-catalyzed oxidation of glucose at C2 and Ni/C-catalyzed hydrogenation of d-glucosone at C1 selectively gives fructose in 77 % yield. Starting from upstream substrates such as α-cellulose and starch, fructose was also generated with similar efficiency and selectivity by the combination of enzymatic and heterogeneous catalysis. This method constitutes a new means of preparing fructose from biomass-derived substrates in an efficient fashion.
Epicatechin Adducting with 5-Hydroxymethylfurfural as an Inhibitory Mechanism against Acrylamide Formation in Maillard Reactions
Qi, Yajing,Zhang, Hui,Zhang, Hao,Wu, Gangcheng,Wang, Li,Qian, Haifeng,Qi, Xiguang
, p. 12536 - 12543 (2018/11/25)
This study aimed to investigate the inhibitory mechanism of epicatechin (EC) on the formation of acrylamide in Maillard reactions. The glucose + asparagine model is a typical chemical system used to investigate acrylamide formation. 5-Hydroxymethylfurfural (HMF) is an important carbonyl intermediate in Maillard reactions and can also react with asparagine to form acrylamide. Time courses showed that EC inhibited more HMF than acrylamide in the glucose + asparagine model heated at 180 °C. The reduction of EC on acrylamide formation in the HMF + asparagine model was about 70%, while that in the glucose + asparagine model was about 50%. Moreover, HMF decreased significantly faster when it was heated in the presence of EC. Liquid chromatography-mass spectrometry analysis revealed the formation of adducts between EC and HMF, and the dimeric adducts were verified in fried potato chips. These results suggested that the condensation of EC and HMF was one of the key steps leading to the inhibition of acrylamide. UV-visible spectra analysis showed that some polymerization products had absorption in the visible region and contributed to the development of browning, which was underestimated in the past.
Enzymatic Cascade Catalysis for the Synthesis of Multiblock and Ultrahigh-Molecular-Weight Polymers with Oxygen Tolerance
Liu, Zhifen,Lv, Yue,An, Zesheng
supporting information, p. 13852 - 13856 (2017/10/09)
Synthesis of well-defined multiblock and ultrahigh-molecular-weight (UHMW) polymers has been a perceived challenge for reversible-deactivation radical polymerization (RDRP). An even more formidable task is to synthesize these extreme polymers in the presence of oxygen. A novel methodology involving enzymatic cascade catalysis is developed for the unprecedented synthesis of multiblock polymers in open vessels with direct exposure to air and UHMW polymers in closed vessels without prior degassing. The success of this methodology relies on the extraordinary deoxygenation capability of pyranose oxidase (P2Ox) and the mild yet efficient radical generation by horseradish peroxidase (HRP). The facile and green synthesis of multiblock and UHMW polymers using biorenewable enzymes under environmentally benign and scalable conditions provides a new pathway for developing advanced polymer materials.
Formation of Reactive Intermediates, Color, and Antioxidant Activity in the Maillard Reaction of Maltose in Comparison to d -Glucose
Kanzler, Clemens,Schestkowa, Helena,Haase, Paul T.,Kroh, Lothar W.
, p. 8957 - 8965 (2017/10/17)
In this study, the Maillard reaction of maltose and d-glucose in the presence of l-alanine was investigated in aqueous solution at 130 °C and pH 5. The reactivity of both carbohydrates was compared in regards of their degradation, browning, and antioxidant activity. In order to identify relevant differences in the reaction pathways, the concentrations of selected intermediates such as 1,2-dicarbonyl compounds, furans, furanones, and pyranones were determined. It was found, that the degradation of maltose predominantly yields 1,2-dicarbonyls that still carry a glucosyl moiety and thus subsequent reactions to HMF, furfural, and 2-acetylfuran are favored due to the elimination of d-glucose, which is an excellent leaving group in aqueous solution. Consequently, higher amounts of these heterocycles are formed from maltose. 3-deoxyglucosone and 3-deoxygalactosone represent the only relevant C6-1,2-dicarbonyls in maltose incubations and are produced in nearly equimolar amounts during the first 60 min of heating as byproducts of the HMF formation.
Biochemical characteristics of Trametes multicolor pyranose oxidase and Aspergillus niger glucose oxidase and implications for their functionality in wheat flour dough
Decamps, Karolien,Joye, Iris J.,Haltrich, Dietmar,Nicolas, Jacques,Courtin, Christophe M.,Delcour, Jan A.
experimental part, p. 1485 - 1492 (2012/05/20)
Similar to glucose oxidase (GO), pyranose oxidase (P2O) may well have desired functionalities in some food applications in general, particularly breadmaking. As its name implies, P2O oxidises a variety of monosaccharides. P2O purified from a culture of Trametes multicolor (P2O-Tm) had high affinity towards d-glucose (KM = 3.1 mM) and lower affinity to other monosaccharides. GO from Aspergillus niger (GO-An) had a KM value of 225 mM towards glucose, which points to a significant difference in glucose affinity between the two enzymes. Furthermore, P2O-Tm had higher affinity towards O2 (KM = 0.46 mM) than GO-An (KM = 2.9 mM). Dehydroascorbic acid did not accept electrons in the reactions catalysed by P2O-Tm and GO-An. For the same activity towards glucose in saturating conditions, the rate of ferulic acid oxidation in a model system and of thiol oxidation in a wheat flour extract were higher with P2O-Tm, than with GO-An. The demonstrated differences in properties and functional features between P2O-Tm and GO-An allow prediction of differences in functional behaviour of the enzymes, in food applications.
Temperature decrease (30-25 °c) influence on bi-enzymatic kinetics of D-glucose oxidation
Ene, Manuela Diana,Maria, Gheorghe
experimental part, p. 19 - 24 (2012/09/08)
Previous batch experiments reported by Maria et al. [1] for d-glucose oxidation in the presence of pyranose 2-oxidase (P2Ox from Coriolus sp. expressed in E. coli) and catalase at 30 °C and optimal pH = 6.5 have been extended to a lower temperature of 25 °C. This modification influences the process performance in different ways, leading to a higher activity of catalase for decomposing H2O2 by-product, thus maintaining its concentration to negligible levels. While the presence of catalase has a favourable effect at 30 °C on prolonging P2Ox life-time, a quick P2Ox inactivation is observed at 25 °C due to the high levels of the resulted oxidative intermediates. While the P2Ox activity does not vary too much in the range of 25-30 °C, a significant decline of the main reaction rate with the increase of catalase/P2Ox ratio is reported for both temperatures. Estimated rate constants of a proposed kinetic model are compared to the literature data, being used to predict the favourable operating conditions for this complex bi-enzymatic system.
Bioconversion of d-glucose into d-glucosone by immobilized glucose 2-oxidase from Coriolus versicolor at moderate pressures
Karmali, Amin,Coelho, José
experimental part, p. 168 - 173 (2011/08/06)
The immobilized glucose 2-oxidase (pyranose oxidase, pyranose:oxygen-2- oxidoreductase, EC 1.1.3.10) from Coriolus versicolor was used to convert d-glucose into d-glucosone at moderate pressures, up to 150 bar, with compressed air in a modified commercial batch reactor. Several parameters affecting biocatalysis at moderate pressures were investigated as follows: pressure, different forms of immobilized biocatalysts, glucose concentration, pH, temperature and the presence of catalase. Glucose 2-oxidase (GOX2) was purified by immobilized metal affinity chromatography on epoxy-activated Sepharose 6B-IDA-Cu(II) column at pH 6.0. Purified enzyme and catalase were immobilized into a polyethersulfone (PES) membrane in the presence of glutaraldehyde and gelatin. Enhancement of the bioconversion of d-glucose was done by the pressure since an increase in the pressure with compressed air increases the conversion rates. The optimum temperature and pH for bioconversion of d-glucose were found to be 62 °C and pH 6.0, respectively and the activation energy (E a) was 28.01 kJ mol-1. The apparent kinetic constants (V′max, K′m, K′cat and Kcat/K′m) for this bioconversion were 2.27 U mg-1 protein, 11.15 mM, 8.33 s-1 and 747.38 s-1 M-1, respectively. The immobilized biomass of C. versicolor as well as crude extract containing GOX2 activity were also useful for bioconversion of d-glucose at 65 bar with a yield of 69.9 ± 3.8% and 91.3 ± 1.2%, respectively. The immobilized enzyme was apparently stable for several months without any significant loss of enzyme activity. On the other hand, this immobilized enzyme was also stable at moderate pressures, since such pressures did not affect significantly the enzyme activity.
A conserved active-site threonine is important for both sugar and flavin oxidations of pyranose 2-oxidase
Pitsawong, Warintra,Sucharitakul, Jeerus,Prongjit, Methinee,Tan, Tien-Chye,Spadiut, Oliver,Haltrich, Dietmar,Divne, Christina,Chaiyen, Pimchai
experimental part, p. 9697 - 9705 (2011/03/20)
Pyranose 2-oxidase (P2O) catalyzes the oxidation by O2 of D-glucose and several aldopyranoses to yield the 2-ketoaldoses and H 2O2. Based on crystal structures, in one rotamer conformation, the threonine hydroxyl of Thr169 forms H-bonds to the flavin-N5/O4 locus, whereas, in a different rotamer, it may interact with either sugar or other parts of the P2O·sugar complex. Transient kinetics of wild-type (WT) and Thr169 → S/N/G/A replacement variants show that D-Glc binds to T169S, T169N, and WT with the same Kd (45-47mM), and the hydride transfer rate constants (kred) are similar (15.3-9.7 s -1 at 4 °C ). kred of T169G with D-glucose (0.7 s -1, 4 °C) is significantly less than that of WT but not as severely affected as in T169A (kred of 0.03 s-1 at 25 °C). Transient kinetics of WT and mutants using D-galactose show that P2O binds D-galactose with a one-step binding process, different from binding of D-glucose. In T169S, T169N, and T169G, the overall turnover with D-Gal is faster than that of WT due to an increase of kred. In the crystal structure of T169S, Ser169 Oγassumes a position identical to that of Oγ1 in Thr169; in T169G, solvent molecules may be able to rescue H-bonding. Our data suggest that a competent reductive half-reaction requires a side chain at position 169 that is able to form an H-bond within the ES complex. During the oxidative half-reaction, all mutants failed to stabilize a C4a-hydroperoxyflavin intermediate, thus suggesting that the precise position and geometry of the Thr169 side chain are required for intermediate stabilization.
Thermostable variants of pyranose 2-oxidase showing altered substrate selectivity for glucose and galactose
Spadiut, Oliver,Nguyen, Tien-Thanh,Haltrich, Dietmar
experimental part, p. 3465 - 3471 (2011/07/31)
The homotetrameric flavoprotein pyranose 2-oxidase (P2Ox) has several proposed biotechnological applications, among others as a biocatalyst for carbohydrate transformations toward higher-value products. To improve some of the catalytic properties of P2Ox from Trametes multicolor, we selected a semirational enzyme engineering approach, namely, saturation mutagenesis of the amino acid His 450 located at a pivotal point of the active site loop and subsequent screening of the libraries thus obtained for improved activity with the sugar substrate D-galactose. A variant with improved catalytic characteristics identified was H450G, which showed a significant, 3.6-fold decrease In KM together with a 1.4-fold increase in κcat for its substrate D-galactose and an overall improvement in the catalytic efficiency by a factor of 5. By combining H450G with other amino acid replacements, we obtained the P2Ox variants H450G/V546C and H450G/E542K/V546C, which can be of interest for applications in food industry due to their increased activity with D-galactose, high activity with D-glucose, and considerably increased stability for the latter variant. While the His-tagged recombinant wild-type enzyme strongly prefers D-glucose to D-galactose as its substrate, H450G/E542K/V546C converts both sugars, which are found in lactose hydrolysates, concomitantly, as was shown by laboratory-scale biotransformation experiments. The 2-keto sugars thus obtained can conveniently be reduced to the corresponding ketoses D-fructose and D-tagatose. 2010 American Chemical Society.
Degradation of glucose: reinvestigation of reactive α-dicarbonyl compounds
Jenny, Gobert,Glomb, Marcus A.
experimental part, p. 8591 - 8597 (2010/07/15)
Maillard reactions influence the formation of flavor and color in processed foods in an important way. Reducing sugars and amino acids ultimately react to stable end products. To elucidate the complex formation pathways a vast number of experiments have b
