Cross- linked enzyme aggregates of recombinantxylanase for hemicelluloses to xylooligosaccharides

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, d...

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Main Author:	Shalyda, Md Shaarani
Format:	Thesis
Language:	English
Published:	2018
Subjects:	QK Botany TP Chemical technology
Online Access:	http://umpir.ump.edu.my/id/eprint/30102/1/Cross-%20linked%20enzyme%20aggregates%20of%20recombinantxylanase%20for%20hemicelluloses%20to%20xylooligosaccharides.wm.pdf
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spelling	my-ump-ir.301022023-05-30T07:47:46Z Cross- linked enzyme aggregates of recombinantxylanase for hemicelluloses to xylooligosaccharides 2018-03 Shalyda, Md Shaarani QK Botany TP Chemical technology 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-CLEAsilanized 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-CLEAsilanized 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. 2018-03 Thesis http://umpir.ump.edu.my/id/eprint/30102/ http://umpir.ump.edu.my/id/eprint/30102/1/Cross-%20linked%20enzyme%20aggregates%20of%20recombinantxylanase%20for%20hemicelluloses%20to%20xylooligosaccharides.wm.pdf pdf en public phd doctoral Universiti Teknologi Malaysia Faculty of Chemical and Energy Engineering Md. Illias, Rosli
institution	Universiti Malaysia Pahang Al-Sultan Abdullah
collection	UMPSA Institutional Repository
language	English
advisor	Md. Illias, Rosli
topic	QK Botany TP Chemical technology
spellingShingle	QK Botany TP Chemical technology Shalyda, Md Shaarani Cross- linked enzyme aggregates of recombinantxylanase for hemicelluloses to xylooligosaccharides
description	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-CLEAsilanized 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-CLEAsilanized 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.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Shalyda, Md Shaarani
author_facet	Shalyda, Md Shaarani
author_sort	Shalyda, Md Shaarani
title	Cross- linked enzyme aggregates of recombinantxylanase for hemicelluloses to xylooligosaccharides
title_short	Cross- linked enzyme aggregates of recombinantxylanase for hemicelluloses to xylooligosaccharides
title_full	Cross- linked enzyme aggregates of recombinantxylanase for hemicelluloses to xylooligosaccharides
title_fullStr	Cross- linked enzyme aggregates of recombinantxylanase for hemicelluloses to xylooligosaccharides
title_full_unstemmed	Cross- linked enzyme aggregates of recombinantxylanase for hemicelluloses to xylooligosaccharides
title_sort	cross- linked enzyme aggregates of recombinantxylanase for hemicelluloses to xylooligosaccharides
granting_institution	Universiti Teknologi Malaysia
granting_department	Faculty of Chemical and Energy Engineering
publishDate	2018
url	http://umpir.ump.edu.my/id/eprint/30102/1/Cross-%20linked%20enzyme%20aggregates%20of%20recombinantxylanase%20for%20hemicelluloses%20to%20xylooligosaccharides.wm.pdf
_version_	1783732136654667776

Cross- linked enzyme aggregates of recombinantxylanase for hemicelluloses to xylooligosaccharides

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