IMMOBILIZATION OF STARGENE ?-AMYLASE ON SILICA MODIFIED WITH PROPYLAMINE-GLUTARALDEHYDE AND ITS PERFORMANCE

• Main Author: Afrilia Dwi Nanda, Vilda
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/65437
• Institution: Institut Teknologi Bandung

Enzymes are widely used in industry because they are biocatalysts and work specifically. However, because the enzyme is soluble in water, it is difficult to separate from the substrate and product, and it cannot be used repeatedly. As a result, using enzymes on a large scale comes at a high cost. As a result, enzyme immobilization is required so that the enzyme can be used repeatedly. The goal of this study was to immobilize Stargene's ?-amylase on propylamine-glutaraldehyde-modified silica. In this study, silica was synthesized with tetraethyl orthosilicate (TEOS) precursor, then modified with 3-aminopropyl trimethoxysilane (APTMS), and finally modified with glutaraldehyde. In addition, the covalent bond technique was used to immobilize enzymes on the modified silica matrix. The 3,5-dinitrosalicylic acid (DNS) method is used in the immobilized enzyme performance test to determine the concentration of reducing sugars produced by starch hydrolysis and the Bradford method to determine protein concentration. The FTIR spectrum shows a typical vibrational absorption band from the Si-O-Si vibration in the area around 1366?956 cm?1, indicating the formation of silica. At a wavenumber of 930 cm?1 there is an absorption band of Si-C vibrations which indicates that silica propylamine has been formed. There is an absorption band from C-H vibrations at wave number 2987 cm?1 and a vibration absorption band from C=O at wave number 1622 cm?1, indicating that silica-propylamine-glutaraldehyde has been formed. There is a C-N vibrational absorption band at a wavenumber of 1301 cm?1 and an N-H vibrational absorption band at a wavenumber of 1490 cm?1 in the FTIR spectrum of enzyme-modified silica, indicating that ?-amylase has immobilized on the modified silica. The morphology of silica, silica-propylamine, and silica-propylamine glutaraldehyde is spherical, with sizes of 1.13?1.61 ?m, 2.02?2.90 ?m, and 2.62?4.04 ?m, respectively, as shown in the SEM image. SEM image of immobilized ?-amylases with a size of 14.7?15.1 ?m. The optimum reaction pH for free and immobilized ?-amylases was 6,5, the optimum reaction times for free and immobilized ?-amylases were 10 and 60 minutes, the optimum reaction temperatures for free and immobilized ?-amylases were 60°C, and the optimum starch concentration for free and immobilized ?-amylases was 2% w/v. The immobilization of ?-amylases was successful until the seventh use, with activity to hydrolyze starch. Furthermore, ?-amylases are stable and can hydrolyze starch for up to 14 days after storage.