NOVEL CHITOSAN (CHI)/POLYPROPYLENE (PP) FILM MODIFIED WITH CETYL TRIMETHYLAMMONIUM BROMIDE (CTAB) AS SUPPORT FOR LIPASE IMMOBILIZATION AND ITS CHARACTERIZATION ASPECTS

• Main Author: RAHMAWATI (NIM :20514029), ISTIQOMAH
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/22643
• Institution: Institut Teknologi Bandung

Enzymes is catalyst with characteristics as unstable, can not be used repeatedly and continuously, high production and isolation cost. Enzyme immobilization is <br /> <br /> solutions of these problems. Enzyme immobilization is method for enzymes placement physically or chemically in an area so that the enzyme can be used <br /> <br /> repeatedly. Lipase immobilization is a very promising method to improve the performance of lipase. Immobilized lipase system can be used continuously, has high catalytic control effectiveness, and reduce the cost of insulation and operations. Immobilization system of lipase into chitosan/polypropilena film modified with CTAB was prepared by immobilizing lipase in a sandwich support system. The lipase was placed between PP membrane modified with CTAB and chitosan nanoparticles. The lipase was immobilized in a support system by carrier binding method. The success of immobilized lipase system formation was shown from the Particle Size Analyzer (PSA), The Fourier Transform Infrared spectroscopy (FTIR), contact angle measurement, and Scanning Electron Microscopy (SEM) results. PSA results showed that chitosan nanoparticle size obtained was 70.5 nm. FTIR results were obtained gradually along each of <br /> <br /> manufacture process, i.e. modification of PP with CTAB was evidenced by peaks at 729, 911, 960, and 1473 cm-1, while the presence of lipase on PP-CTAB-Lipase <br /> <br /> system was showed by peaks at 1086, 1370, 1660, and 3323 cm-1, and the presence of chitosan was confirmed by the appearance of peak at 1585 cm-1. The results of contact angle measurements for water showed an alteration too. <br /> <br /> Polypropylene membrane having hydrophobic properties shown a contact angle at 117 o and decreased until 88 <br /> <br /> o showing hydrophilicity increment due membrane surface modification with CTAB. Lipase immobilization with high hydrophylicity at modified polypropylene membrane caused contact angle decreased at 32 o , and the presence of chitosan caused contact angle increment until 66 o <br /> <br /> due hydrophobic backbone from chitosan. Meanwhile, SEM results indicated a change of surface morphology on which there was pore closure of immobilized lipase <br /> <br /> system membrane. The catalytic activity of immobilized lipase system shown an iv increment compared with native enzyme (increment of catalytic activity was three <br /> <br /> and five-times compared with native enzyme for PP-CTAB-Lip-Chi and PPCTAB- Lip sequentially). The presence of chitosan in the immobilized lipase system increase the stability of lipase against temperature, re-use, and storage effect. The activity of lipase immobilization showed a higher stability against temperature than the free enzyme as evidenced by the presence of the enzyme <br /> <br /> activity at 60 oC while free enzyme was inactivated. Lipase immobilized also showed a higher stability against storage than the free enzyme as evidenced by the <br /> <br /> presence of enzyme activity in the eighth and thirteenth day of storage time (PPCTAB- lipase and PP-CTAB-lipase-Chitosan system respectively) while the free enzyme already inactivated on the 4th of storage day. Lipase immobilized showed the stability against the re-use that can not be obtained from the use of the free enzyme, while immobilized lipase can be used and still showed activity in the 15th and 20th of re-use (system PP-CTAB-lipase and PP-CTAB-lipase-Chitosan, respectively). The analysis of membrane potential showedan interesting feature for every manufacture process from the immobilized lipase system. The shift of membrane potential features indicated a polarity changing of membrane for every manufacture process from immobilized lipase system and the result wasappropiate with contact angle result. A shift of membran potential value caused by substrate injection showed catalytic reaction has been succeeded by electrokinetic properties consideration.