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273 results on '"Nyanhongo, Gibson S."'

3. Delivery of Biomolecules Using Chitosan Wound Dressings

Author

Guebitz, Georg M., Pellis, Alessandro, Nyanhongo, Gibson S., Abe, Akihiro, Editorial Board Member, Albertsson, Ann-Christine, Editorial Board Member, Coates, Geoffrey W., Editorial Board Member, Genzer, Jan, Editorial Board Member, Kobayashi, Shiro, Editorial Board Member, Lee, Kwang-Sup, Editorial Board Member, Leibler, Ludwik, Editorial Board Member, Long, Timothy E., Editorial Board Member, Möller, Martin, Editorial Board Member, Okay, Oguz, Editorial Board Member, Percec, Virgil, Editorial Board Member, Tang, Ben Zhong, Editorial Board Member, Terentjev, Eugene M., Editorial Board Member, Theato, Patrick, Editorial Board Member, Voit, Brigitte, Editorial Board Member, Wiesner, Ulrich, Editorial Board Member, Zhang, Xi, Editorial Board Member, Jayakumar, R., editor, and Prabaharan, M., editor

Published
2021
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6. Effect of Salts on Laccase‐Catalyzed Polymerization of Lignosulfonate.

Author

Mayr, Sebastian A., Rennhofer, Harald, Gille, Lars, Schwaiger, Nikolaus, Nyanhongo, Gibson S., Weiss, Renate, and Guebitz, Georg M.

Subjects
LACCASE, ELECTRON paramagnetic resonance, SUSTAINABLE chemistry, COUNTER-ions, SMALL-angle scattering, POLYMERIZATION
Abstract

Enzymatic polymerization of lignosulfonate (LS) has a high potential for various applications ranging from coatings to adhesives. Here, the effect of different ions in low concentrations on enzymatic polymerization of LS was investigated, including salt solutions consisting of mono‐ and dicarboxylic acids, sulfate, phosphate and chloride with sodium as counter ion. LS polymerization was followed by viscometry and size exclusion (SEC) chromatography. Interestingly, there was only a small effect of ions on the activity of the laccase on standard substrate ABTS, while the effect on polymerization of LS was substantially different. The presence of acetate led to a 39 % higher degree of polymerization (DP) for LS. Small angle X‐ray scattering (SAXS) revealed that the structure of the enzyme was largely unaffected by the ions, while the determination of the zeta potential showed that those ions conveying higher negative surface charges onto LS particles showed lower DPs, than those not affecting the surface charge. Further, electron paramagnetic resonance (EPR) spectroscopy showed 5‐times higher intensity in phenoxyl radicals for the monovalent ions compared to the divalent ones. It was concluded that the DPs of LS could be tuned in the presence of certain ions, by facilitating the interaction between the laccase substrate‐binding site and the LS molecules. [ABSTRACT FROM AUTHOR]

Published
2024
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35. Enhanced energy savings in enzymatic refining of hardwood and softwood pulp.

Author

Nagl, Martin, Haske-Cornelius, Oskar, Bauer, Wolfgang, Nyanhongo, Gibson S., and Guebitz, Georg M.

Subjects
SOFTWOOD, CELLULASE, XYLANASES, HARDWOODS, HIGH performance liquid chromatography, POLYSACCHARIDES
Abstract

Background: Pulp refining is an energy consuming, but integral part of paper production with the aim to increase tensile strength and smoothness of paper sheets. Commercial enzyme formulations are used to lower the energy requirements by pre-treatment of pulp before refining. However, a high number of different commercial enzyme products are available on the market containing enzymes of varying origin and composition, which complicates the prediction of their behavior, especially using different pulp types. Results: Endoglucanase-rich enzyme formulations were characterized regarding enzyme activity at different temperatures, resulting in a significant decrease of activity above 70 °C. Some enzyme preparations additionally contained arabinosidase, xylanase and β-glucosidase activity consequently resulting in a release of xylose and glucose from pulp as determined by high-performance liquid chromatography. Interestingly, one enzyme formulation even showed lytic polysaccharide monooxygenase (LPMO) activity of 3.05 nkat mg−1. A correlation between enzyme activity using the endoglucanase specific derivatized cellopentaose (CellG5) substrate and enzyme performance in laboratory PFI (Papirindustriens forskningsinstitut) refining trials was observed on softwood pulp resulting in a maximum increase in the degree of refining values from 27.7°SR to 32.7°SR. When added to a purified endoglucanase enzyme (31.6°SR), synergistic effects were found for cellobiohydrolase II (34.7°SR) or β-glucosidase enzymes (35.7°SR) in laboratory refining. Comparison with previously obtained laboratory refining results on hardwood pulp allowed differences in enzyme performance based on varying pulp types to be elucidated. Conclusions: Interestingly, the individual enzymes indeed showed different refining effects on softwood and hardwood pulp. This difference could be predicted after development of an adapted enzyme activity assay by combination of the derivatized cellopentaose CellG5 substrate with either softwood or hardwood sulfate pulp. [ABSTRACT FROM AUTHOR]

Published
2023
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41. List of contributors

Author

Agunbiade, Mayowa, Arunima, Aziziyan, Fatemeh, Bhardwaj, Nisha, Bhat, Sarita G., Cascelli, Nicoletta, Castilla-Marroquin, Jesus D., Dabirmanesh, Bahareh, De Chiaro, Addolorata, Farzam, Farnoosh, Guebitz, Georg M., Hernández-Martínez, Ricardo, Hernández-Rosas, Francisco, Jose, Jiya, Khajeh, Khosro, Khera, Khushi, Kudanga, Tukayi, Le Roes-Hill, Marilize, Lettera, Vincenzo, Mehrotra, Rekha, Michel, Hamy, Nemadziva, Blessing, Nyanhongo, Gibson S., Parra-Saldivar, Roberto, Prins, Alaric, Rathod, Virendra K., Romero-Martínez, Daniel, Sajeevan, Shilja, Sannia, Giovanni, Trujillo-Roldán, Mauricio A., Valdez-Cruz, Norma A., Verma, Preeti, Weiss, Renate, Yadav, Aarti, and Yadav, Deepti

Published
2024
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43. Polymerization of lignosulfonates by the laccase-HBT (1-hydroxybenzotriazole) system improves dispersibility

Author

Nugroho Prasetyo, Endry, Kudanga, Tukayi, Østergaard, Lars, Rencoret, Jorge, Gutiérrez, Ana, del Río, José C., Ignacio Santos, J., Nieto, Lidia, Jiménez-Barbero, Jesús, Martínez, Angel T., Li, Jiebing, Gellerstedt, Göran, Lepifre, Stéphane, Silva, Carla, Kim, Su Yeon, Cavaco-Paulo, Artur, Seljebakken Klausen, Bente, Lutnaes, Bjart Frode, Nyanhongo, Gibson S., and Guebitz, Georg M.

Published
2010
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