Kriteria pemilihan kontraktor untuk melaksanakan kontrak pengurusan fasiliti

Enzymes as biocatalysts in industries are more advantageous compared to chemical catalysts because of their low operating conditions, less complexity, and environmentally-friendly property. Laccase, an oxidoreductase enzyme, is foreseen to be used in various industries as a biocatalyst. However, the...

Full description

Saved in:

Bibliographic Details
Main Author:	Mohd. Syukri, Mohd. Syahlan
Format:	Thesis
Language:	English
Published:	2021
Subjects:	TP Chemical technology
Online Access:	http://eprints.utm.my/id/eprint/102222/1/MohdSyahlanPSChE2021.pdf.pdf
Tags:	Add Tag No Tags, Be the first to tag this record!

id	my-utm-ep.102222
record_format	uketd_dc
spelling	my-utm-ep.1022222023-08-09T08:33:13Z Kriteria pemilihan kontraktor untuk melaksanakan kontrak pengurusan fasiliti 2021 Mohd. Syukri, Mohd. Syahlan TP Chemical technology Enzymes as biocatalysts in industries are more advantageous compared to chemical catalysts because of their low operating conditions, less complexity, and environmentally-friendly property. Laccase, an oxidoreductase enzyme, is foreseen to be used in various industries as a biocatalyst. However, the use of free laccase in industries often suffers some limitations, such as high production cost, instability issues, low recovery, and reusability problems. These problems can be overcome by enzyme immobilization technology, which offers enhancements to free enzyme's stability. The advent of nanotechnology has introduced electrospun nanofiber mat as a carrier for enzyme immobilization. The mat is foreseen to be implemented in the enzymatic membrane bioreactors of continuous flow processes. In this study, polyethylene terephthalate (PET) was grafted with maleic anhydride (MAH) (PET-g-MAH) and spun through electrospinning into nanofiber mats with an average fiber diameter of 844 ± 149 nm before it was used as the carrier of immobilized laccase. Three different immobilization methods were used: physical adsorption on PET nanofiber mats, covalent bonding, and covalent bonding of cross-linked laccase aggregate with glutaraldehyde as the cross-linker. The combination of 0.28 mg/ml laccase concentration, pH 3 citrate buffer, 0.45 % (v/v) glutaraldehyde concentration, 1.5 hr of covalent bonding time at 22.7 oC, and 1 hr of cross-linking time at 20 oC contributed to the optimum immobilization yield (87.64 %). The adsorption of laccase on PET-g-MAH nanofiber mats obeyed the pseudo-first-order, and the biosorption isotherms correlated well with the Freundlich isotherm model. The optimized immobilized laccase was able to withstand high temperature (60 oC) and also oxidized 2, 2-azino-bis 3-ethylbenzothiazoline-6- sulfonic acid (ABTS) at a broad range of pH (pH 3 to pH 6) and temperature (20 oC to 70 oC). It also managed to retain 77.55 % of its initial activity after 10 repeated cycles of ABTS oxidation and 29.22 % after 30 days storage at 4 oC in pH 3 buffer. In conclusion, the results showed that the laccase immobilized on the PET-g-MAH nanofiber mat might have great potential to be used in industries. 2021 Thesis http://eprints.utm.my/id/eprint/102222/ http://eprints.utm.my/id/eprint/102222/1/MohdSyahlanPSChE2021.pdf.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:145950 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 Mohd. Syukri, Mohd. Syahlan Kriteria pemilihan kontraktor untuk melaksanakan kontrak pengurusan fasiliti
description	Enzymes as biocatalysts in industries are more advantageous compared to chemical catalysts because of their low operating conditions, less complexity, and environmentally-friendly property. Laccase, an oxidoreductase enzyme, is foreseen to be used in various industries as a biocatalyst. However, the use of free laccase in industries often suffers some limitations, such as high production cost, instability issues, low recovery, and reusability problems. These problems can be overcome by enzyme immobilization technology, which offers enhancements to free enzyme's stability. The advent of nanotechnology has introduced electrospun nanofiber mat as a carrier for enzyme immobilization. The mat is foreseen to be implemented in the enzymatic membrane bioreactors of continuous flow processes. In this study, polyethylene terephthalate (PET) was grafted with maleic anhydride (MAH) (PET-g-MAH) and spun through electrospinning into nanofiber mats with an average fiber diameter of 844 ± 149 nm before it was used as the carrier of immobilized laccase. Three different immobilization methods were used: physical adsorption on PET nanofiber mats, covalent bonding, and covalent bonding of cross-linked laccase aggregate with glutaraldehyde as the cross-linker. The combination of 0.28 mg/ml laccase concentration, pH 3 citrate buffer, 0.45 % (v/v) glutaraldehyde concentration, 1.5 hr of covalent bonding time at 22.7 oC, and 1 hr of cross-linking time at 20 oC contributed to the optimum immobilization yield (87.64 %). The adsorption of laccase on PET-g-MAH nanofiber mats obeyed the pseudo-first-order, and the biosorption isotherms correlated well with the Freundlich isotherm model. The optimized immobilized laccase was able to withstand high temperature (60 oC) and also oxidized 2, 2-azino-bis 3-ethylbenzothiazoline-6- sulfonic acid (ABTS) at a broad range of pH (pH 3 to pH 6) and temperature (20 oC to 70 oC). It also managed to retain 77.55 % of its initial activity after 10 repeated cycles of ABTS oxidation and 29.22 % after 30 days storage at 4 oC in pH 3 buffer. In conclusion, the results showed that the laccase immobilized on the PET-g-MAH nanofiber mat might have great potential to be used in industries.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Mohd. Syukri, Mohd. Syahlan
author_facet	Mohd. Syukri, Mohd. Syahlan
author_sort	Mohd. Syukri, Mohd. Syahlan
title	Kriteria pemilihan kontraktor untuk melaksanakan kontrak pengurusan fasiliti
title_short	Kriteria pemilihan kontraktor untuk melaksanakan kontrak pengurusan fasiliti
title_full	Kriteria pemilihan kontraktor untuk melaksanakan kontrak pengurusan fasiliti
title_fullStr	Kriteria pemilihan kontraktor untuk melaksanakan kontrak pengurusan fasiliti
title_full_unstemmed	Kriteria pemilihan kontraktor untuk melaksanakan kontrak pengurusan fasiliti
title_sort	kriteria pemilihan kontraktor untuk melaksanakan kontrak pengurusan fasiliti
granting_institution	Universiti Teknologi Malaysia
granting_department	Faculty of Engineering - School of Chemical & Energy Engineering
publishDate	2021
url	http://eprints.utm.my/id/eprint/102222/1/MohdSyahlanPSChE2021.pdf.pdf
_version_	1776100872371044352

Kriteria pemilihan kontraktor untuk melaksanakan kontrak pengurusan fasiliti

Similar Items