Immobilization of lipase candida rugosa on nylon-6 grafted poly vinylbenzyl chloride (PVBC) /
Enzyme immobilization is a special technique to overcome the shortcoming of free enzyme such as deactivation, stability and reusability of enzyme. One of the main factors that have influence on the efficacy of immobilized enzyme is the use of suitable support. The features of support must possess hi...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
Kuala Lumpur :
Kulliyyah of Engineering, International Islamic University Malaysia,
2019
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| Subjects: | |
| Online Access: | http://studentrepo.iium.edu.my/handle/123456789/4872 |
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| Summary: | Enzyme immobilization is a special technique to overcome the shortcoming of free enzyme such as deactivation, stability and reusability of enzyme. One of the main factors that have influence on the efficacy of immobilized enzyme is the use of suitable support. The features of support must possess high mechanical strength, inert and free from catalytic reaction and ability to increase enzyme activity and specificity. In this study, nylon-6 fibre grafted with poly vinylbenzyl chloride (PVBC) was used as support to immobilize Candida rugosa lipase enzyme by covalent attachment. The aim of this study is to find the optimum parameters for lipase immobilization on nylon-6 grafted PVBC. Further, temperature and pH stability, reusability, storage stability as well as kinetic study were carried out and finally the optimum condition of immobilized lipase was applied for biodiesel production from castor oil. At the beginning of the experiment, nylon-6 grafted PVBC was activated with ethanolamine to introduce amine group (NH2) on the fibre to facilitate immobilization of lipase. Successful amination of the support was confirmed using FTIR and SEM. Lipase immobilization on the fibre was optimized using response surface methodology (RSM). The parameters optimized were incubation time (3 to 7 hr), pH (7.0 to 9.0) and lipase concentration (0.4 to 1.0 mg/mL) with lipase activity as response. Maximum activity was obtained at pH 8 with lipase concentration of 0.7 mg/mL for 5 hr incubation time. Under these conditions, lipase activity was 2.281 U/mg. Additionally, the lipase activity for immobilized and free was characterized in terms of temperature, pH, reusability and storage stability. The model from RSM obtained R-square value of 0.9705 and P-value < 0.001, indicating the model is significant. Optimum temperatures for both immobilized and free lipases were 45 °C meanwhile the best pH condition for lipase activity was at pH 8 and pH 7 respectively. Kinetic study KM and Vmax for immobilized and free lipase were identified. The value of KM for immobilized and free lipase is 1.71 mM and 2.01 mM meanwhile the value of Vmax is 17.76 µM/min and 14.43 µM/min respectively. Following the reusability study, the immobilized lipase retained more than 20% from initial activity after 8 cycles. Furthermore, storage stability was stored in 4 °C for up to 30 days and the results shows the activity of immobilized and free lipase was retained 78% and 69% respectively. Finally, immobilized and free lipase was further evaluated by transesterification reaction for biodiesel production from castor oil. The condition was 1 to 4 molar ratio of oil to methanol, 45 °C, 200 rpm agitation speed for 24 hr incubation time. GC/MS was used to analyse the production of biodiesel which is fatty acid methyl ester (FAME). Methyl heptadecanoate, 61.87% is the major FAME product for immobilized meanwhile, methyl oleate, 61.48% is the major product for free lipase. |
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| Physical Description: | xiv, 92 leaves : colour illustrations ; 30cm. |
| Bibliography: | Includes bibliographical references (leaves 78-84). |