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Synthesis and applications of aminated biopolymers
Cellulose and chitin have a significant role in the biorefinery where biomass is converted into value-added products. Native cellulose and chitin are known to be insoluble in most common organic and aqueous solvents and are therefore physically and chemically modified with different functionalities...
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| Format: | Thesis |
| Language: | English English |
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Department of Chemistry
2025
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| _version_ | 1867613245615898624 |
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| access_status_str | Open Access |
| author | Phillips, Thaakirah |
| author2 | Jardine, Mogamat |
| author_browse | Jardine, Mogamat Phillips, Thaakirah |
| author_facet | Jardine, Mogamat Phillips, Thaakirah |
| author_sort | Phillips, Thaakirah |
| collection | Thesis |
| description | Cellulose and chitin have a significant role in the biorefinery where biomass is converted into value-added products. Native cellulose and chitin are known to be insoluble in most common organic and aqueous solvents and are therefore physically and chemically modified with different functionalities to improve solubility to enable further application and modulate bioactivity. The introduction of amino groups into biopolymers is one method to improve solubility in water and enhance other properties such as bioactivity. The solubility of polymers in water is advantageous and enables opportunities for applications in many industries. A simple, green and sustainable synthetic method was sought as an improvement to prior methods using hazardous reagents and producing immense amounts of waste. Innovative synthetic methods were developed for the synthesis of amino- and diamino celluloses. A sustainable, economically viable process for biopolymer amination was sought via substitution of C-6 tosyl esters or via reductive amination of biopolymer aldehyde derivatives. To this end, C-6 amino cellulose was synthesised by a novel synthetic pathway in which cellulose is firstly tosylated using a surfactant-mediated solvent system to yield DMSO-soluble cellulose tosylates. Subsequently the C-6 partially tosylated cellulose was subjected to a Swern-like oxidation to yield the required C-6 aldehyde functionality primed for reductive amination. The same oxidation-reductive amination strategy was attempted on chitin or chitosan. The established periodate oxidation of cellulose provided dialdehyde cellulose (DAC) ready for reductive amination. The synthesised diamino and amino celluloses were DMSO-soluble and were tested for cytotoxicity against brain cancer cell lines. Cytotoxicity studies showed that the aminated celluloses did not display any inherent anticancer activity, however, it would be suitable for drug conjugation and delivery. Previous studies have showed the successful use of recyclable 6-deoxy-6-amino chitosan as an aqueous-soluble solid support for platinum group metal catalysts. This motivated the use of an amination strategy for the immobilisation of pyridoxal and pyridoxal 5'-phosphate (PLP) for application in non-enzymatic deamination of L-phenylalanine to phenylpyruvate. An ionic complex between PLP and Q188 was formed and successfully utilised to convert L- phenylalanine into phenylpyruvate, however, the polymer complex showed a decline in activity over time possibly due to the leaching of PLP. Therefore, immobilisation of PLP via covalent bonding was explored, however, the pyridoxal immobilised biopolymers synthesised were insoluble in water and could not be used in simulating non-enzymatic deamination reactions. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/41900 |
| institution | University of Cape Town (South Africa) |
| language | English eng |
| last_indexed | 2026-06-10T12:33:05.164Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Department of Chemistry |
| publisherStr | Department of Chemistry |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/41900 Synthesis and applications of aminated biopolymers Phillips, Thaakirah Jardine, Mogamat Cellulose Chitin Cellulose and chitin have a significant role in the biorefinery where biomass is converted into value-added products. Native cellulose and chitin are known to be insoluble in most common organic and aqueous solvents and are therefore physically and chemically modified with different functionalities to improve solubility to enable further application and modulate bioactivity. The introduction of amino groups into biopolymers is one method to improve solubility in water and enhance other properties such as bioactivity. The solubility of polymers in water is advantageous and enables opportunities for applications in many industries. A simple, green and sustainable synthetic method was sought as an improvement to prior methods using hazardous reagents and producing immense amounts of waste. Innovative synthetic methods were developed for the synthesis of amino- and diamino celluloses. A sustainable, economically viable process for biopolymer amination was sought via substitution of C-6 tosyl esters or via reductive amination of biopolymer aldehyde derivatives. To this end, C-6 amino cellulose was synthesised by a novel synthetic pathway in which cellulose is firstly tosylated using a surfactant-mediated solvent system to yield DMSO-soluble cellulose tosylates. Subsequently the C-6 partially tosylated cellulose was subjected to a Swern-like oxidation to yield the required C-6 aldehyde functionality primed for reductive amination. The same oxidation-reductive amination strategy was attempted on chitin or chitosan. The established periodate oxidation of cellulose provided dialdehyde cellulose (DAC) ready for reductive amination. The synthesised diamino and amino celluloses were DMSO-soluble and were tested for cytotoxicity against brain cancer cell lines. Cytotoxicity studies showed that the aminated celluloses did not display any inherent anticancer activity, however, it would be suitable for drug conjugation and delivery. Previous studies have showed the successful use of recyclable 6-deoxy-6-amino chitosan as an aqueous-soluble solid support for platinum group metal catalysts. This motivated the use of an amination strategy for the immobilisation of pyridoxal and pyridoxal 5'-phosphate (PLP) for application in non-enzymatic deamination of L-phenylalanine to phenylpyruvate. An ionic complex between PLP and Q188 was formed and successfully utilised to convert L- phenylalanine into phenylpyruvate, however, the polymer complex showed a decline in activity over time possibly due to the leaching of PLP. Therefore, immobilisation of PLP via covalent bonding was explored, however, the pyridoxal immobilised biopolymers synthesised were insoluble in water and could not be used in simulating non-enzymatic deamination reactions. 2025-09-19T12:37:12Z 2025-09-19T12:37:12Z 2025 2025-09-19T09:07:41Z Thesis / Dissertation Masters MSc http://hdl.handle.net/11427/41900 en eng application/pdf Department of Chemistry Faculty of Science University of Cape Town |
| spellingShingle | Cellulose Chitin Phillips, Thaakirah Synthesis and applications of aminated biopolymers |
| thesis_degree_str | Master's |
| title | Synthesis and applications of aminated biopolymers |
| title_full | Synthesis and applications of aminated biopolymers |
| title_fullStr | Synthesis and applications of aminated biopolymers |
| title_full_unstemmed | Synthesis and applications of aminated biopolymers |
| title_short | Synthesis and applications of aminated biopolymers |
| title_sort | synthesis and applications of aminated biopolymers |
| topic | Cellulose Chitin |
| url | http://hdl.handle.net/11427/41900 |
| work_keys_str_mv | AT phillipsthaakirah synthesisandapplicationsofaminatedbiopolymers |