Cross-linked enzyme aggregates of recombinant xylanase for conversion of hemicelluloses to xylooligosaccharides
Thesis (PhD. (Bioprocess Engineering))
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| Format: | Thesis |
| Language: | English |
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Universiti Teknologi Malaysia
2024
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| Online Access: | http://openscience.utm.my/handle/123456789/1215 |
| _version_ | 1811131821321093120 |
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| author | Md. Shaarani @ Md. Nawi, Shalyda |
| author_facet | Md. Shaarani @ Md. Nawi, Shalyda |
| author_sort | Md. Shaarani @ Md. Nawi, Shalyda |
| collection | OpenScience |
| description | Thesis (PhD. (Bioprocess Engineering)) |
| first_indexed | 2024-09-23T23:50:10Z |
| format | Thesis |
| id | oai:openscience.utm.my:123456789/1215 |
| institution | Universiti Teknologi Malaysia - OpenScience |
| language | English |
| last_indexed | 2024-09-23T23:50:10Z |
| publishDate | 2024 |
| publisher | Universiti Teknologi Malaysia |
| record_format | dspace |
| spelling | oai:openscience.utm.my:123456789/12152024-06-22T18:00:39Z Cross-linked enzyme aggregates of recombinant xylanase for conversion of hemicelluloses to xylooligosaccharides Md. Shaarani @ Md. Nawi, Shalyda Hemicellulose Enzymes—Biotechnology Immobilized enzymes—Biotechnology Thesis (PhD. (Bioprocess Engineering)) Hemicelluloses are heterogeneous branched polymers of sugars that exist abundantly in nature. Enzymatic hydrolysis is envisioned as a highly potential method in converting hemicelluloses into fuels and value-added chemicals. However, the use of free enzyme is hampered by low operational stability, difficulty in recovery and non-reusability, which requires for enzyme immobilization. Carrier-bound immobilization leads to utilization of high cost matrices, clogging of filters during downstream processing and presence of large amounts of non-catalytic ballast. Therefore, cross-linked enzyme aggregates (CLEA), a carrier-free technology that combines purification (precipitation) and immobilization into a single operation and does not require purified enzymes, is the solution to these problems. In this study, a recombinant xylanase (Xyl) from Trichoderma reesei was immobilized using three approaches: Xyl-CLEA, Xyl-CLEA-BSA (bovine serum albumin) and Xyl-CLEA-silanized maghemite. The use of ethanol as precipitant (1:9 volume ratio of enzyme to precipitant), glutaraldehyde (0.2:1 of glutaraldehyde to enzyme of 100 mM concentration) as cross-linking agent and the introduction of (3-aminopropyl) triethoxysilane (APTES) silanized maghemite (0.0075:1 of silanized maghemite to enzyme) prevailed in forming xylanase CLEAs with good enzyme activity recovery (78 %), thermal stability (50 % retained activity) and reusability (50 % retained activity). The Xyl-CLEA-silanized maghemite enhanced the activity recovery 1.66- and 1.50-fold compared to Xyl-CLEA and Xyl-CLEA-BSA, respectively. At elevated temperature of 60 °C and pHs of 3.0 and 8.0, Xyl-CLEA-silanized maghemite achieved better stability compared to the other CLEAs and free enzyme. Xyl-CLEA-silanized maghemite also successfully retained more than 50 % of its activity after 6 cycles, whereas Xyl-CLEA only retained approximately 10 % after 5 cycles. Therefore, the performance of Xyl-CLEA-silanized maghemite was further investigated by xylan hydrolysis under optimised reaction conditions. Xylooligosaccharides yield was slightly improved by 1.26- fold compared to the free enzyme. Kinetic parameters confirmed that CLEA immobilization did affect the productivity of the designed biocatalyst Faculty of Chemical Engineering 2024-06-22T09:53:33Z 2024-06-22T09:53:33Z 2018 Thesis Dataset http://openscience.utm.my/handle/123456789/1215 en application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf Universiti Teknologi Malaysia |
| spellingShingle | Hemicellulose Enzymes—Biotechnology Immobilized enzymes—Biotechnology Md. Shaarani @ Md. Nawi, Shalyda Cross-linked enzyme aggregates of recombinant xylanase for conversion of hemicelluloses to xylooligosaccharides |
| title | Cross-linked enzyme aggregates of recombinant xylanase for conversion of hemicelluloses to xylooligosaccharides |
| title_full | Cross-linked enzyme aggregates of recombinant xylanase for conversion of hemicelluloses to xylooligosaccharides |
| title_fullStr | Cross-linked enzyme aggregates of recombinant xylanase for conversion of hemicelluloses to xylooligosaccharides |
| title_full_unstemmed | Cross-linked enzyme aggregates of recombinant xylanase for conversion of hemicelluloses to xylooligosaccharides |
| title_short | Cross-linked enzyme aggregates of recombinant xylanase for conversion of hemicelluloses to xylooligosaccharides |
| title_sort | cross linked enzyme aggregates of recombinant xylanase for conversion of hemicelluloses to xylooligosaccharides |
| topic | Hemicellulose Enzymes—Biotechnology Immobilized enzymes—Biotechnology |
| url | http://openscience.utm.my/handle/123456789/1215 |
| work_keys_str_mv | AT mdshaaranimdnawishalyda crosslinkedenzymeaggregatesofrecombinantxylanaseforconversionofhemicellulosestoxylooligosaccharides |