CO-immobilization of cellulase and xylanase on magnetically-separable hierarchically-ordered mesocellular mesoporous silica

Lignocellulosic biomass that exist abundantly in nature is a potential source for producing environmentally sustainable biobased chemicals. Lignocellulosic materials can be converted into fuels and value-added chemicals by the method of enzymatic hydrolysis using cellulase and xylanase enzymes. Howe...

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Main Author:	Sulaiman, Nurul Jannah
Format:	Thesis
Language:	English
Published:	2020
Subjects:	TP Chemical technology
Online Access:	http://eprints.utm.my/id/eprint/92542/1/NurulJannahPSChE2020.pdf.pdf
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spelling	my-utm-ep.925422021-09-30T15:11:24Z CO-immobilization of cellulase and xylanase on magnetically-separable hierarchically-ordered mesocellular mesoporous silica 2020 Sulaiman, Nurul Jannah TP Chemical technology Lignocellulosic biomass that exist abundantly in nature is a potential source for producing environmentally sustainable biobased chemicals. Lignocellulosic materials can be converted into fuels and value-added chemicals by the method of enzymatic hydrolysis using cellulase and xylanase enzymes. However, the use of free enzymes is hampered by the low storage stability, difficulty in recovery and non-reusability of the enzymes, which leads to the need for enzyme immobilization. Several inorganic carriers are potentially suitable for enzymatic immobilization, by means of several different techniques. Enzyme immobilization in magnetically-separable hierarchically-ordered mesocellular mesoporous silica (M-HMMS) is an alternative method for producing efficient biocatalyst. In this study, cellulase and xylanase were immobilized using three approaches: enzyme adsorption, enzyme adsorption and cross-linking and enzyme adsorption, precipitation and cross-linking (EAPC). The best precipitant, cross-linker and immobilization method for cellulase and xylanase co-immobilization were tert-butanol, glutaraldehyde and EAPC, respectively. The optimum cellulase and xylanase activity retention were achieved using 2 mL of enzymes, 1 mg: 0.15 mL of magnetic silica-to-enzyme ratio, adsorption temperature of 26 ºC, adsorption time of 40 min, adsorption agitation rate of 162 rpm, 1:11 mL volume of enzyme-to-precipitant ratio, 0.05 % v/v of glutaraldehyde concentration, cross-linking temperature of 37 ºC, 2 hours of cross-linking time and cross-linking agitation rate of 300 rpm. The biocatalysts prepared under optimized condition retained the activity more than 90% with improved storage stability (above 60 % after 14 days). Adsorption study showed that the pseudo-second-order kinetic model and Kolmogorov-Erofeev-Kazeeva-Avrami-Mampel model were the best models to represent the kinetic adsorption process of cellulase and xylanase on M-HMMS. The sorption process was found to be physisorption for cellulase and chemisorption for xylanase, as predicted by the activation energies. The results suggest that co-immobilized cellulase and xylanase in M-HMMS is a promising biocatalyst. 2020 Thesis http://eprints.utm.my/id/eprint/92542/ http://eprints.utm.my/id/eprint/92542/1/NurulJannahPSChE2020.pdf.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:139313 phd doctoral Universiti Teknologi Malaysia Faculty of Engineering - School of Chemical & Energy Engineering
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	TP Chemical technology
spellingShingle	TP Chemical technology Sulaiman, Nurul Jannah CO-immobilization of cellulase and xylanase on magnetically-separable hierarchically-ordered mesocellular mesoporous silica
description	Lignocellulosic biomass that exist abundantly in nature is a potential source for producing environmentally sustainable biobased chemicals. Lignocellulosic materials can be converted into fuels and value-added chemicals by the method of enzymatic hydrolysis using cellulase and xylanase enzymes. However, the use of free enzymes is hampered by the low storage stability, difficulty in recovery and non-reusability of the enzymes, which leads to the need for enzyme immobilization. Several inorganic carriers are potentially suitable for enzymatic immobilization, by means of several different techniques. Enzyme immobilization in magnetically-separable hierarchically-ordered mesocellular mesoporous silica (M-HMMS) is an alternative method for producing efficient biocatalyst. In this study, cellulase and xylanase were immobilized using three approaches: enzyme adsorption, enzyme adsorption and cross-linking and enzyme adsorption, precipitation and cross-linking (EAPC). The best precipitant, cross-linker and immobilization method for cellulase and xylanase co-immobilization were tert-butanol, glutaraldehyde and EAPC, respectively. The optimum cellulase and xylanase activity retention were achieved using 2 mL of enzymes, 1 mg: 0.15 mL of magnetic silica-to-enzyme ratio, adsorption temperature of 26 ºC, adsorption time of 40 min, adsorption agitation rate of 162 rpm, 1:11 mL volume of enzyme-to-precipitant ratio, 0.05 % v/v of glutaraldehyde concentration, cross-linking temperature of 37 ºC, 2 hours of cross-linking time and cross-linking agitation rate of 300 rpm. The biocatalysts prepared under optimized condition retained the activity more than 90% with improved storage stability (above 60 % after 14 days). Adsorption study showed that the pseudo-second-order kinetic model and Kolmogorov-Erofeev-Kazeeva-Avrami-Mampel model were the best models to represent the kinetic adsorption process of cellulase and xylanase on M-HMMS. The sorption process was found to be physisorption for cellulase and chemisorption for xylanase, as predicted by the activation energies. The results suggest that co-immobilized cellulase and xylanase in M-HMMS is a promising biocatalyst.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Sulaiman, Nurul Jannah
author_facet	Sulaiman, Nurul Jannah
author_sort	Sulaiman, Nurul Jannah
title	CO-immobilization of cellulase and xylanase on magnetically-separable hierarchically-ordered mesocellular mesoporous silica
title_short	CO-immobilization of cellulase and xylanase on magnetically-separable hierarchically-ordered mesocellular mesoporous silica
title_full	CO-immobilization of cellulase and xylanase on magnetically-separable hierarchically-ordered mesocellular mesoporous silica
title_fullStr	CO-immobilization of cellulase and xylanase on magnetically-separable hierarchically-ordered mesocellular mesoporous silica
title_full_unstemmed	CO-immobilization of cellulase and xylanase on magnetically-separable hierarchically-ordered mesocellular mesoporous silica
title_sort	co-immobilization of cellulase and xylanase on magnetically-separable hierarchically-ordered mesocellular mesoporous silica
granting_institution	Universiti Teknologi Malaysia
granting_department	Faculty of Engineering - School of Chemical & Energy Engineering
publishDate	2020
url	http://eprints.utm.my/id/eprint/92542/1/NurulJannahPSChE2020.pdf.pdf
_version_	1747818600545124352

CO-immobilization of cellulase and xylanase on magnetically-separable hierarchically-ordered mesocellular mesoporous silica

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