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Bioresource Technology Nov 2019Spent coffee grounds are a huge residual stream from instant coffee makers. The production of spent coffee oil and molecular weight fractionated hemicellulose...
Production of molecular weight fractionated hemicelluloses hydrolyzates from spent coffee grounds combining hydrothermal extraction and a multistep ultrafiltration/diafiltration.
Spent coffee grounds are a huge residual stream from instant coffee makers. The production of spent coffee oil and molecular weight fractionated hemicellulose hydrolysates via supercritical CO and a hydrothermal treatment followed by concentration, separation, and purification through cascade ultrafiltration/diafiltration (30-10-5 kDa) was studied. Hemicelluloses extraction yield reached 3.49 g/100 g of dry defatted spent coffee after 40 min at 160 °C. The ultrafiltration system allowed concentrating up to 5-fold certain groups of hemicellulose, being most of them retained in the first membrane. Hemicellulose concentration and molecular weight of the feed exerted a great influence on the mass transfer through the membrane due to the formation of aggregates. However, purification through diafiltration allowed both to decrease by-products retentions from 45.6% to 8.7%, increasing the molecular weight of each fraction. Six hemicellulose products were obtained with purities between 83.7 and 97.8 wt% and weight-average molecular weights between 1641 and 49,733 Da.
Topics: Coffee; Molecular Weight; Polysaccharides; Ultrafiltration
PubMed: 31419707
DOI: 10.1016/j.biortech.2019.121940 -
Environmental Science and Pollution... Feb 2021The effects of low molecular weight organic acids (LMWOAs) on the adsorption of quinclorac by sepiolite were investigated using laboratory batch technique. Experiments...
The effects of low molecular weight organic acids (LMWOAs) on the adsorption of quinclorac by sepiolite were investigated using laboratory batch technique. Experiments were conducted with two natural sepiolite samples with different crystal structures and chemical compositions and high-purity sepiolite. The LMWOAs used were acetic, oxalic, and citric acid. And the adsorption mechanism was characterized using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Our analysis revealed that adsorption of quinclorac on α-sepiolite and β-sepiolite was inhibited in the presence of 4 mmol L LMWOAs, whereas LMWOAs stimulated the adsorption of quinclorac in the high-purity sepiolite. Inhibition or stimulation varied across the different types of organic acids. The adsorption isotherms in the presence of 4 mmol L LMWOAs were better explained by Freundlich and linear model. The effect of organic acid concentrations (0-32 mmol L) on the adsorption of quinclorac by the three sepiolite samples varies greatly depending on the type of organic acid and the property of sepiolite. FTIR, XRD, and XPS analyses showed that LMWOAs bound strongly to the Si-O bond structure, and Si-O-quinclorac-acetic acid (oxalic acid or citric acid) was formed on the surface of β-sepiolite. The adsorption of quinclorac by β-sepiolite was via hydrogen bond, complexation reactions, and charge transfer in the presence of LMWOAs. These results indicate that LMWOAs affect quinclorac adsorption through various interactions involving competition, electrostatic attraction, bridging action, and hydrogen bonding.
Topics: Adsorption; Magnesium Silicates; Molecular Weight; Quinolines
PubMed: 33146822
DOI: 10.1007/s11356-020-11405-8 -
Biochimica Et Biophysica Acta Apr 1957
Topics: Chymotrypsinogen; Enzyme Precursors; Molecular Weight
PubMed: 13426203
DOI: 10.1016/0006-3002(57)90147-6 -
Carbohydrate Polymers Jun 2012Recently, low-molecular-weight hyaluronic acid has been reported to have novel features, such as free radical scavenging activities, antioxidant activities, promotion of...
Recently, low-molecular-weight hyaluronic acid has been reported to have novel features, such as free radical scavenging activities, antioxidant activities, promotion of excisional wound healing, etc. In the present work, degradation of native hyaluronic acid by ozone treatment was performed for preparation of low-molecular-weight hyaluronic acid. The molecular weight of native hyaluronic acid was reduced from 1535 to 87 kDa for 120 min at 40°C. The rate of reduction of molecular weight was 94.33%. The FT-IR, 13C NMR, and UV-vis spectra suggested that there was no obvious modification of chemical structure of low-molecular-weight hyaluronic acid. The use of degradation of native hyaluronic acid by ozone treatment can be a useful alternative for production of low-molecular-weight hyaluronic acid.
Topics: Hyaluronic Acid; Molecular Weight; Ozone
PubMed: 24750777
DOI: 10.1016/j.carbpol.2012.03.081 -
Iranian Biomedical Journal Nov 2022Background: Hyaluronic acid (HA), a natural polymer with wide applications in biomedicine and cosmetics, is mainly produced by Streptococcal fermentation at industrial...
BACKGROUND
Background: Hyaluronic acid (HA), a natural polymer with wide applications in biomedicine and cosmetics, is mainly produced by Streptococcal fermentation at industrial scale. In the present study, chemical random mutagenesis was used for development of Streptococcus equisimilis group G mutant strains with high HA productivity.
METHODS
Methods: The optimum of the pH of culture condition and cultivation time for HA production by wild strain group G were assessed. At first, two rounds of mutation at different concentrations of NTG was used for mutagenesis. Then, the nonhemolytic and hyaluronidase-negative mutants were screened on the blood and HA agar. HA productivity and molecular weight were determined by carbazole assay, agarose gel electrophoresis and specific staining. Moreover, stability of the high producer mutants was evaluated within 10 generations.
RESULTS
Results: The results showed that the wild-type strain produced 1241 ± 2.1 µg/ml of HA at pH 5.5 and 4 hours of cultivation, while the screened mutants showed a 16.1-45.5% increase in HA production. Two mutant strains, named Gm2-120-21-3 (2470 ± 8.1 µg/ml) and Gm2-120-21-4 (2856 ± 4.2 µg/ml), indicated the highest titer and a consistent production. The molecular weight (Mw) of HA for the mutants was less than 160 kDa, considering as a low Mw HA.
CONCLUSION
Conclusion: The mutant strains producing a low polydisperse, as well as low Mw of HA with high titer might be regarded as potential industrial strains for HA production after further safety investigations.
Topics: Hyaluronic Acid; Molecular Weight; Agar; Streptococcus
PubMed: 36437793
DOI: 10.52547/ibj.3789 -
Journal of Magnetic Resonance (San... Jan 2023The HMQC pulse sequence and variants thereof have been exploited in studies of high molecular weight protein complexes, taking advantage of the fact that fast and slow...
The HMQC pulse sequence and variants thereof have been exploited in studies of high molecular weight protein complexes, taking advantage of the fact that fast and slow relaxing magnetization components are sequestered along two distinct magnetization transfer pathways. Despite the simplicity of the HMQC scheme an even shorter version can be designed, based on elimination of the terminal refocusing period, as a further means of increasing signal. Here we present such an experiment, and show that significant sensitivity gains, in some cases by factors of two or more, are realized in studies of proteins varying in molecular masses from 100 kDa to 1 MDa.
Topics: Carbon Isotopes; Molecular Weight; Proteins; Nuclear Magnetic Resonance, Biomolecular
PubMed: 36508761
DOI: 10.1016/j.jmr.2022.107326 -
Rapid Communications in Mass... 2001Process improvements in the synthesis of therapeutic agents and their intermediates are often facilitated by identification of reaction by-products. Analysis by liquid...
Process improvements in the synthesis of therapeutic agents and their intermediates are often facilitated by identification of reaction by-products. Analysis by liquid chromatography/mass spectrometry (LC/MS) with electrospray ionization is a powerful approach for obtaining molecular weight information for these compounds. Such analyses are well suited for 'open-access' mass spectrometry using generic chromatographic conditions, provided spectral interpretation for unknown compounds is facile. We have developed a software application (MassAssign) that facilitates automated data processing and molecular weight assignment for chromatographic peaks detected by any standard ultraviolet-visible wavelength detector. The program assigns [M + H](+) ions (and thus molecular weight) in the mass spectra using predetermined criteria. This evaluation process differentiates [M + H](+) ions from other signals in a complex mass spectrum such as those resulting from chromatographic coelution or the presence of multiple species (i.e., fragment ions, singly charged ions, doubly charged ions, adduct ions, proton-bound dimers, etc.). Once the program has evaluated all ions in a mass spectrum that exceed a preset abundance threshold, MassAssign reports either a numeric value-indicating the chromatographic peak consists of a single component having the displayed molecular weight, 'MC'-indicating the peak consisted of multiple components, or 'ND'-that a molecular weight could not be determined unequivocally. The performance of the program was evaluated by comparing mass assignments made by MassAssign against manual interpretation for 55 samples analyzed by positive electrospray ionization using a generic HPLC method. Correct molecular weight assignments were obtained in 90% of the cases.
Topics: Algorithms; Autoanalysis; Molecular Weight; Pharmaceutical Preparations; Spectrometry, Mass, Electrospray Ionization; Spectrophotometry, Ultraviolet
PubMed: 11746916
DOI: 10.1002/rcm.519 -
Journal of Food and Drug Analysis Jan 2020Hyaluronic acid (HA), a multi-functional material, has a high dispersion in molecular weight, and the functions of HA are determined through the size. Nevertheless,...
Hyaluronic acid (HA), a multi-functional material, has a high dispersion in molecular weight, and the functions of HA are determined through the size. Nevertheless, hyaluronic acid mixtures are not easily separated due to their polydispersity. In this study, a capillary electrophoresis strategy was developed for resolution of different molecular-weight HA without enzymatic digestion. Here, hyaluronic acid mixtures with low molecular weight (380 kD; LHA) and high molecular weight (2180 kD; HHA) were successfully resolved by the SDS integrated with low molecular-weight polymer in capillary electrophoresis. By optimizing experimental conditions, the separation of LHA and HHA was completed within 14 min. The optimal conditions were as follows: the running buffer was 25 mM borate buffer (pH 9.75) containing 30 mM SDS and 10% polyethylene glycol (MW: 8000); applied voltage was 20 kV (detector at cathode side) and separation temperature was set at 25 °C. The data of method validation showed that calibration plots were linear (r ≥ 0.9977) over a range of 10-50 μg/mL for LHA, and 40-200 μg/mL for HHA. In the evaluation of precision and accuracy for this method, the RSD and RE values were all less than 4.2%. This fascinating technique was successfully applied to the quality control of cosmetic and pharmaceutical containing different ratios of LHA and HHA, and it was feasible for serving as a tool to quantitatively analyze different sizes of HA for clinical survey.
Topics: Chromatography, Micellar Electrokinetic Capillary; Hyaluronic Acid; Molecular Weight; Polymers
PubMed: 31883604
DOI: 10.1016/j.jfda.2019.10.005 -
Yakugaku Zasshi : Journal of the... 2023The effects of drugs and other low-molecular-weight compounds are complex and may be unintended by the developer. These compounds and drugs should be avoided if these...
The effects of drugs and other low-molecular-weight compounds are complex and may be unintended by the developer. These compounds and drugs should be avoided if these unintended effects are harmful; however, unintended effects are not always as harmful as suggested by drug repositioning. Therefore, a comprehensive understanding of complex drug actions is essential. Omics data can be regarded as the nonarbitrary transformation of biological information about a sample into comprehensive numerical information comprising multivariate data with a large number of variables. However, the changes are often based on a small number of elements in different dimensions (i.e., latent variables). The omics data of compound-treated samples comprehensively capture the complex effects of compounds, including their unrecognized aspects. Therefore, finding latent variables in these data is expected to contribute to the understanding of multiple effects. In particular, it can be interpreted as decomposing multiple effects into a smaller number of easily understandable effects. Although latent variable models of omics data have been used to understand the mechanisms of diseases, no approach has considered the multiple effects of compounds and their decomposition. Therefore, we propose to decompose and understand the multiple effects of low-molecular-weight compounds without arbitrariness and have been developing analytical methods and verifying their usefulness. In particular, we focused on classical factor analysis among latent variable models and have been examining the biological validity of the estimates obtained under linear assumptions.
Topics: Molecular Weight; Factor Analysis, Statistical; Drug Repositioning
PubMed: 36724926
DOI: 10.1248/yakushi.22-00156-2 -
Nature Nov 1965
Topics: Chromatography, Gel; Fibrinolytic Agents; Molecular Weight
PubMed: 5870107
DOI: 10.1038/208894a0