Degree Of Polymerization Distribution Research Articles

Enzymatic Synthesis of α-Glucan Microparticles Using Amylosucrases from Bifidobacterium Species and Its Physicochemical Properties.

α-Glucan microparticles (GMPs) have significant potential as high-value biomaterials in various industries. This study proposes a bottom-up approach for producing GMPs using four amylosucrases from Bifidobacterium sp. (BASs). The physicochemical characteristics of these GMPs were analyzed, and the results showed that the properties of the GMPs varied depending on the type of enzymes used in their synthesis. As common properties, all GMPs exhibited typical B-type crystal patterns and poor colloidal dispersion stability. Interestingly, differences in the physicochemical properties of GMPs were generated depending on the synthesis rate of linear α-glucan by the enzymes and the degree of polymerization (DP) distribution. Consequently, we found differences in the properties of GMPs depending on the DP distribution of linear glucans prepared with four BASs. Furthermore, we suggest that precise control of the type and characteristics of the enzymes provides the possibility of producing GMPs with tailored physicochemical properties for various industrial applications.

A novel approach to building digital twin transformers by combining virtual-real sensing: An example of degree of polymerization distribution

Digital twin (DT) in the power industry faces challenges due to complex structures and limited distributed sensors for power equipment. In this work, a novel approach combining virtual-real sensing (VRS) was used to build DT for transformers, taking the degree of polymerization (DP) distribution as an example. Temperature and moisture distributions were calculated, and a dynamic deduction model for DP distribution was established. The visualization of DP distribution was achieved through surface-rebuild. Results showed a 3.5% error in temperature distribution compared to monitoring data. Moisture distribution was concentrated in the cardboard and bottom solid insulation, reaching 3.2% in the 48th year. DP distribution pattern aligned with Cigre’s report, with the lowest value at the hot spot location of the LV windings, deduced to be 252.15 in the 48th year. This study provides a data base for realizing transformers DT and is a key step towards building a vital DT transformer.

Comparison of the prebiotic properties of native chicory and synthetic inulins using swine fecal cultures.

Inulin-type fructans are known to exert different effects on the fermentation profile depending on the average and range of the degree of polymerization (DP). Here, swine fecal cultures were used to investigate the prebiotic properties of native chicory inulin (NIN), extracted from the chicory root, and synthetic inulin (SIN), which has a narrower DP distribution than NIN. Both NIN and SIN showed prebiotic effects, but NIN exhibited a significant decrease in pH and increase in the production of propionate and butyrate compared to SIN. There were also differences in the production of succinate and lactate, the precursors of propionate and butyrate, and the relative abundance of associated genes. Furthermore, NIN induced the growth of certain species of Bifidobacterium and Lactobacillus more strongly than SIN. These results suggest that NIN and SIN exhibit different prebiotic properties due to differences in DP, and that NIN might be more beneficial to host health.

Co-production of xylooligosaccharides and activated carbons from Camellia oleifera shell treated by the catalysis and activation of zinc chloride

Camellia oleifera shell (COS) is a worthy byproduct in woody edible oil production enriched in hemicellulose and lignin. This paper aims to explore the high-value transformation of COS for the production of xylooligosaccharides (XOS) with main degree of polymerization (DP) of 2–5 by the catalysis of ZnCl2. The effect of pretreatment temperature, reaction time and ZnCl2 concentration on the contents and DP distributions of XOS were analyzed. Moderate reaction conditions tended to achieve high content XOS, and the maximum value 61.38% and 14.39 g/L of XOS yield and concentration, respectively, peaked at 170 °C for 30 min using 0.5% (w/w) ZnCl2. The first time the solid residues derived from the production process of XOS were used as the precursor for the co-production of activated carbons (AC). The maximum iodine values and BET surface area were 5623.94 mg/g and 1244.46 m2/g, respectively, using 2.20 M ZnCl2 as the activating agent.

Nanoribbon network formation of enzymatically synthesized cellulose oligomers through dispersion stabilization of precursor particles

Cellulose oligomers were synthesized via cellodextrin phosphorylase-catalyzed reactions using α-D-glucose 1-phosphate monomers and D-glucose primers. The products prepared at relatively high primer concentrations self-assembled into highly grown nanoribbon network structures. The nanoribbons were composed of cellulose oligomers with degree-of-polymerization (DP) values of 8-9 with certain degrees of DP distribution and displayed the cellulose II allomorph. A formation mechanism for the unique nanostructures was proposed based on analyses of reaction time-dependent differences of the product solutions.

Chain length distribution of inulin from dahlia tubers as influenced by the extraction method

ABSTRACTA variety of fructans occurs in plants, having various configuration and chain lengths from 3 up to a few hundred fructose units. The structurally simplest fructan is a linear inulin, where the fructose units are linked by β-2,1 bonds, present mostly in Asteraceae and Cichorioideae (e.g. dahlia). The pharmacological effects of fructans depend mainly on the degree of polymerization (DP). Hence, a controlled DP distribution profile is essential for the expected spectrum of pharmacological activities. The aim of this study was to purify fructans from dahlia (Dahlia x hortensis Guill. cv.‘Ken’s Flame’) tubers with different inulin chain lengths profile. We developed the selective preparative approach, followed by qualitative and quantitative analyses by pulsed amperometry-high performance anion-exchange chromatography. The fructans were obtained by the extraction of dahlia tubers with water, concentrated under vacuum, subsequent precipitation of carbohydrate fraction by ethanol, followed by purification using four different combinations of absorbents such as Dowex® ion-exchange resin, aluminium oxide, calcium carbonate, and activated carbon. The highest content of short-chain inulin (38%) was in the crude fraction and after the separation on Al2O3 and CaCO3. All methods selectively enriched inulin in the middle-length chains. The highest concentration of high-quality long-chain inulin (16%) was obtained by consecutive washing through CaCO3, Al2O3, Dowex, and charcoal. This complex was also the most balanced in terms of the proportion among short-, medium-, and long-chain inulin (33%, 43%, and 16%, respectively).

Self-Assembly of Cellulose Oligomers into Nanoribbon Network Structures Based on Kinetic Control of Enzymatic Oligomerization.

The ability to chemically synthesize desired molecules followed by their in situ self-assembly in reaction solution has attracted much attention as a simple and environmentally friendly method to produce self-assembled nanostructures. In this study, α-d-glucose 1-phosphate monomers and cellobiose primers were subjected to cellodextrin phosphorylase-catalyzed reverse phosphorolysis reactions in aqueous solution in order to synthesize cellulose oligomers, which were then in situ self-assembled into crystalline nanoribbon network structures. The average degree-of-polymerization (DP) values of the cellulose oligomers were estimated to be approximately 7-8 with a certain degree of DP distribution. The cellulose oligomers crystallized with the cellulose II allomorph appeared to align perpendicularly to the base plane of the nanoribbons in an antiparallel manner. Detailed analyses of reaction time dependence suggested that the production of nanoribbon network structures was kinetically controlled by the amount of water-insoluble cellulose oligomers produced.

Quantitative enzymatic production of sialylated galactooligosaccharides with an engineered sialidase from Trypanosoma rangeli

Sialylated galactooligosaccharides (GOS) represent a potential infant formula ingredient, which is believed to contribute with a combination of the beneficial properties of the prebiotic GOS as well as of sialylated human milk oligosaccharides. Sialylated GOS do not exist in natural milk, but can be produced from κ(kappa)-casein glycomacropeptide (CGMP), a sialylated side stream component from cheese-making, by sialidase-catalyzed transsialylation. Using a rationally designed mutant of the sialidase from Trypanosoma rangeli, Tr13, with enhanced transsialylation activity, six different GOS preparations with a varying degree of polymerization (DP) were effectively sialylated with molar yields of 20–30% on the CGMP sialyl in batch reactions. The rate of sialylation of the individual DPs was largely dependent on the DP distribution in each GOS preparation, and Tr13 catalysis did not discriminate against large GOS molecules, providing the novelty point that GOS molecules are sialylated independently of their size by Tr13. Using CGMP, GOS, and Tr13, the production of gram-scale quantities of sialyl-GOS was achieved in 20L volume reactions. Compared to the benchmark transsialidase from pathogenic Trypanosoma cruzi, the Tr13 was significantly more thermostable. By employing an enzymatic membrane reactor, Tr13 could be recycled and after seven consecutive 1-h reaction cycles, the biocatalytic productivity of the enzyme was increased 7-fold compared to the batch reaction. Assuming that the enzyme may be specific for α-2,3-bound sialyl moieties only, and that only 50% of sialyl linkages in CGMP are α-2,3-linked, the molar yield of sialyl-GOS on the available α-2,3-bound sialyl moieties in CGMP reached 80% in the enzymatic membrane reactor system.

Separation and scavenging superoxide radical activity of chitooligomers with degree of polymerization 6–16

The separation of chitooligomers (COS) with well-defined degree of polymerization (DP) is of interest to further study their bioactivity. However, there has been no report on separation of chitooligomers with DP>6 and the activity of these oligomers is unknown. This paper focuses on separating COS with DP>6 and five fractions were separated from the prepared fully deacetylated chitooligomers mixture by CM Sepharose Fast Flow column and analyzed by HPLC, which mainly contained glucosamine oligomers with DP6–7 (41.31%, 50.22%), DP7–8 (22.47%, 70.13%), DP9–10 (53.06%, 27.99%), DP10–12 (18.45%, 49.36%, 22.31%), and DP>12, respectively. The superoxide radical scavenging activity of each fraction was investigated. The oligomers with DP ranging from 10 to 12 exhibited higher scavenging activity than other fractions and in combination with the DP distribution of fractions, it was further concluded that the chitooligomers with DP11 was likely to be optimal for scavenging superoxide radical activity.

Size exclusion chromatographic and UV-VIS absorption analyses of unbleached and bleached softwood kraft pulps using LiCl/1,3-dimethyl-2-imidazolidinone as a solvent

Abstract Unbleached and bleached kraft pulps and holocellulose prepared from softwood were totally soluble in 8% LiCl/1,3-dimethyl-2-imidazolidinone (LiCl/DMI). The solutions were analyzed by size exclusion chromatography with photodiode array and multi-angle laser light scattering detection (SEC-PDA-MALLS). The mobile phase consisted of 1% LiCl/DMI. The degree of polymerization (DP) and DP distribution of the softwood kraft pulps were determined, as well as the DP distribution of residual lignins based on their UV-VIS absorption patterns. Changes in DP for kraft pulps after a conventional bleaching sequence were evaluated, and the residual lignins were analyzed in the same way. Approximately half of the residual lignin in unbleached and bleached kraft pulps was present in polysaccharide fractions with high DP, which represented approximately 90% of the total yield. Some characteristic differences in the UV-VIS absorption pattern were observed between kraft pulps bleached with oxygen and chlorine. DP, DP distribution of polysaccharides, and distribution of residual lignin were clearly different for unbleached kraft pulp, unbleached sulfite pulp, and holocellulose. An unbleached kraft pulp prepared from hardwood showed different properties to the corresponding softwood preparation. The UV-VIS absorption patterns due to residual lignins were also very characteristic for the various pulps and holocellulose.

Application of Fluorescent Labeling/HPSEC Method to Structural Characterization of the Product from Amylose by Starch Branching Enzyme

The fluorescent labeling/HPSEC method, which is capable of direct determination of a molar distribution, was applied to structural characterization of the product from amylose by starch branching enzyme(SBE) from potato (Solanum tuberosum L.) tubers. The SBE product, excluding possible cyclic molecules, wasa mixture of branched and linear molecules with molar proportions of 65 and 35%, respectively. Size distribution of the product on a molar basis showed three distinct populations at degree of polymerization (DP) of1190, 30 and 7-6, which suggested branched, linear/branched, and linear molecules, respectively. The debranched SBE products exhibited periodicity with intervals of -6, that is, peaks at DP 6, 11, 18 and 29, which implies a helical turn being a unit-structure for SBE action. C-chain of branched molecules of the SBEproduct showed a narrow DP distribution (30-50) which was distinct from that of native amylopectin.

Dynamic Change of Neural Cell Adhesion Molecule Polysialylation on Human Neuroblastoma (IMR-32) and Rat Pheochromocytoma (PC-12) Cells during Growth and Differentiation

Polysialic acid (PSA) is a regulatory epitope of neural cell adhesion molecule (NCAM) in homophilic adhesion of neural cells mediated by NCAM, is also known to be re-expressed in several human tumors, thus serves as an oncodevelopmental antigen. In this study, using a recently developed ultrasensitive chemical method in addition to immunochemical methods, growth stage-dependent and retinoic acid (RA)-induced differentiation-dependent changes of PSA expression in human neuroblastoma (IMR-32) and rat pheochromocytoma (PC-12) cells were analyzed both qualitatively and quantitatively. Both IMR-32 and PC-12 cells expressed PSA on NCAM, and the level of PSA expressed per unit weight of cells increased with post-inoculation incubation time. The most prominent feature was seen at the full confluence stage. RA induced neuronal differentiation in both IMR-32 and CP-12 cells that paralleled the change in the PSA level. Chemical analysis revealed the presence of NCAM glycoforms differing in the degree of polymerization (DP) of oligo/polysialyl chains, whose DP was smaller than 40. DP distribution of PSA was different between the cell lines and was changed by the growth stage and the RA treatment. Thus DP analysis of PSA is important in understanding both mechanism and biological significance of its regulated expression.

13C NMR Analysis of Uniform Heterotactic Oligo(allyl methacrylate) Aiming at Understanding Even—Odd Alternation in Distribution of Degree of Polymerization

The heterotactic oligo(allyl methacrylate)s prepared with t-butyllithium/bis(2, 6-di-t-butylphenoxy)methylaluminum in toluene at −95°C exhibit even—odd alternation in distribution of degree of polymerization (DP) except for 8 mer; oligomers with odd-number DP preferentially formed over those with even-number DP. Uniform oligomers with DPs from 5 to 11 were isolated by fractionating the oligomer with the aid of supercritical fluid chromatography (SFC), and their stereochemical structures were investigated by13C NMR spectroscopy. The NMR analysis for initiating chain-ends of the uniform oligomers revealed evenmdash;odd alternation in distribution of stereoregularity near the initiating chain-end. On the other hand, terminating chain-end analysis showed that the living anions predominantly stayed in r-ended antion state regardless of the DP s of living anions. The fraction of the odd—number DP oligomers (55%), calculated from the peak intensities in the SFC trace, was found to be much lower than that estimated from chain-endanalysis of the original unfractionated oligomer on the assumption that propagation reaction proceeded in a completely heterotactic manner (76%). Structural analysis in the main chain of the each uniform oligomer demonstrated that even—number DP oligomers contained stereochemical defects such as mm sequence, while odd—number DP oligomers consist of almost perfect heterotactic sequence. These results indicate that high-level stereoregulation in the propagation process is also an important factor for the observation of evident even-odd alternation in DP distribution.

Investigation of the Branching Characteristic of Glycogen by Means of Two-Dimensional1H and 13C NMR Spectroscopy

The assignment of 13C and 1H NMR signals of three highly short-chain branched α-D-glucan samples from animal tissue (glycogen) of different provenience, dissolved in dimethylsulfoxide, was achieved using two-dimensional H-H and C-H correlated spectroscopy. The results were comparable to those recently obtained for plant derived short-chain branched α-D-glucans (amylopectin) and non-branched/long-chain branched α-D-glucans (amylose). From these assignments and the integration of pertinent proton signals, the branching degree of the glycogen samples was derived to amount 13.5%. These samples were also analyzed with respect to their degree of polymerization distribution by means of the SEC-DRI/LALLS method. These data and the line broadening of the 1H and 13C NMR spectra of the glycogen samples compared to those of amylopectin and amylose supported the assumption of a broad (homogeneous) distribution of glucose residues in glycogen.

Biological Variation in the Degree of Polymerization of Cotton Lint Cellulose Produced in South Africa

Size-exclusion chromatography coupled with a multi-angle laser light-scattering de tector is a proven and effective technique for measuring absolute molecular weights ( Mw) and molecular weight distributions of cellulose derivatives. Because cellulose is a natural polymer with much variation, average Mw and degree of polymerization (DP) values are of limited value. By plotting and processing absolute DP distributions as directly calculated from the Mw values, an accurate estimate of the DP distribution of a cellulose sample can be obtained. This approach offers the possibility to extend current data processing, which consists mainly of graphic presentations, to exhaustive statistical analyses of the acquired data, previously not possible.

Studies on Fructan Accumulation in Wheat(Triticum aestivum L.). III. Varietal differences in degree of polymerization of fructan and classification by cluster analysis.

Varietal differences in degree of polymerization (DP) of fructan in basal stem including leaf sheath of 29 wheat varieties relating on pedigree of breeding were investigated. Most of the varieties contained a large amount of short-chain fructan in comparison with long-chain fructan. Varietal differences in DP distribution changed largely in accordance with the changes in short-chain fructan. In order to clarify the profiles of DP distribution of fructan in varieties, cluster analysis based on the contents of mono- and disaccharides, short- and long-chain fructan was applied. The varieties were grouped into 4 clusters, namely high and low fructan groups, Velvet and Hon-iku 49. Velvet and Hon-iku 49 are unique in that they contained a lot of long-chain fructan, implying that they are available as genetic resources to increase the fructan contents which is a key factor for wintering ability.

Phase equilibria of quasi‐binary systems consisting of multicomponent polymers 1 and 2. III—Coexistence curve

AbstractAs an extension of the theory established previously (Brit. Polym. J., 23 (1990) 285 and 299), a method for calculating the coexistence curve (CC) was proposed for multicomponent polymer 1/multicomponent polymer 2 system. The polymer composition, molecular weight distribution existing in two liquid phases and their phase volume ratio (R) can be calculated for the systems of polymer whose molecular weight characteristics and the initial composition are known in advance. Systematic computer experiments were carried out to disclose the effect of the average degree of polymerization (DP), the DP distribution of two polymers and the initial concentration on phase diagram including CC. The polydispersity of the polymers can not be ignored in CC as in the case of the cloud point curve (CPC) and the critical solution point (CSP). In the vicinity of CPC, the two‐phase volume ratio changes dramatically corresponding to a slight change in the thermodynamical interaction parameter X12 between polymers 1 and 2. As the initial polymer concentration approaches CSP, R approaches unity and DP distributions of polymers partitioned in two phases reduce to that of the original polymers.

On the distribution of the degree of polymerization occurring in the third kinetic stage of dilute‐acid‐catalyzed degradation of cellulose

AbstractThe distributions of the degree of polymerization (DP) of cellulose degraded in the third kinetic stage, i.e. in the second stage of decreasing reaction rate, obey throughout the most probable (Schulz‐Flory) type, and consequently cellulose specimens degraded at different conditions but with coinciding average DP coincide also with their DP distributions.

Condensation Reaction between Chain Ends of Poly(p-benzamide)

It has been proved experimentally that the condensation reaction between chain ends of poly(p-benzamide), (PBA), takes place and that the degree of polymerization (DP) of PBA increases by annealing in both the solid and liquid-crystalline states. A theoretical analysis of the reaction has shown that the DP distribution of the resultant polymer is again the most probable and the conversion of the reaction by weight is fairly high. The reactivity of PBA in the solid-crystalline state exceeded that in the liquid-crystalline state.

Changes in Molecular Weight of Cellulose in the Pea Epicotyl during Growth

A procedure is described for preparing cellulose nitrate from pea tissues (Pisum sativum L. var. Alaska) in quantitative yield, undegraded and uncontaminated by other polysaccharides. The average degree of polymerization of this product, estimated from viscosity measurements, increased during cell growth and development from a value of about 5000 glucose units in the apical meristem (plumule plus hook) to values near 8000 in fully grown maturing tissues (>20 mm from apex). The cellulose content per cell also increased (approximately 10-fold) during growth in these tissues, as did particulate glucan synthetase activity (3-fold rise). Since the yield of soluble cellulase activity is known to decrease from high values in the meristem to barely detectable amounts in mature tissues, it is suggested that the relative levels and properties of these hydrolytic and synthetic enzyme activities control the amount and degree of polymerization of cellulose formed during cell expansion in the pea epicotyl.Degree of polymerization distribution patterns showed that a low molecular weight component of cellulose (degree of polymerization < 500) was prominent in young tissues whereas high molecular weight components (degree of polymerization > 7000) predominated in mature tissues. Also, cellulose which was formed from radioactive sucrose during 30 minutes of incubation showed a remarkably similar degree of polymerization distribution to cellulose which was present in the tissue at the time of synthesis. It is concluded that new and old parts of the epicotyl cellulose framework are subject to constant modification and equilibration by cellulose-metabolizing enzymes.