Modifikasi zeolit alam sebagai padatan pendukung amobilisasi enzim

Abstract

Material anorganik jenis zeolit sering dimanfaatkan sebagai material pend kung. Zeolit alam mempunyai luas permukaan yang terbatas. Luas perm kaan yang dibutuhkan untuk amobilisasi enzim cukup besar, sehingga perlu dilak kan modifikasi zeolit alam. Zeolit alam dimodifikasi dengan metode dealu inasi, kalsinasi, dan variasi ukuran partikel. Dealuminasi dilakukan dengan cara, eolit alam dengan ukuran masing-masing 30, 60, dan 90 mesh direndam dala HCI 6 N, kemudian dikalsinasi pada suhu 400 selama 4 jam. Zeolit basil modifikasi dianalisis dengan BET untuk menentukan luas permukaan, dan pene tuan keasaman menggunakan adsorpsi gas NH3. Enzim diamobilisasi deng metode adsorpsi fisik. Zeolit dengan ukuran masing-masing 30, 60, dan 90 mesh direndam dalam larutan enzim dan diagitasi selama 24 jam. Enzim yang teram bilisasi ditentukan dengan mengukur kadar protein dalam larutan sebelum dan s sudah adsorpsi dengan metode Lowry. Aktivitas enzim yang teramobilisasi diten kan dengan mengukur kadar glukosa dengan metode Nelson-Somougyi. Dari hasil penelitian dapat ditunjukkan bahwa luas permukaan dan keasa an zeolit basil modifikasi semakin besar dengan meningkatnya ukuran zeolit. Luas permukaan zeolit dengan ukuran masing-masing 30, 60, dan 90 mesh yaitu • 1,95; 110,14; dan 226,15 m2/g, sedangkan keasamannya berturut-turut 1,028 ; 1,1132; dan 1,7619. Kadar protein larutan enzim sebelum adsorpsi yaitu 1,74 g/mL. Prosentase enzim yang teradsorpsi pada zeolit sebelum dilakukan pencu ian dengan ukuran masing-masing 30, 60, dan 90 mesh yaitu 89 %, 95 %, dan 7 %. Aktivitas enzim yang teramobilisasi semakin besar dengan menintkatnya ukuran zeolit. Aktivitas enzim yang teramobilisasi dengan masing¬masint ukuran berturut-turut 0,5346; 0,7676; and 0,9665 mg/100mL. The inorganic materials of the zeolite species usually used as support mate al. The natural zeolite have limited surface areas. The surface areas of the zeolit- to immobilize enzyme have to be large enough, therefore modification of the n tural zeolite is carried out. The natural zeolite was modified by means deal ination, calcinaton, and variation of the particle size. Dealumination by mean the zeolite for each size of 30, 60, and 90 mesh was soaked in HCI 6 N, then acined at 400 °C for 4 hours. The zeolite was analized by BET to determine the s ace areas, then the determination of the acidity use NH3 adsorption. The enzyi e was immobilized by physical adsorption methods. The zeolite for each size s f 30, 60, and 90 mesh was soaked in enzyme solution, then agitated for 24 hours The immobilized enzyme was determined by measuring of the protein conte its in solution before and after adsorption by Lowry method. The activity of imm s ilized enzyme was determined by measuring of the glucose contents by Nels -Somougyi method. The result showed that the surface areas and the acidity of the zeolite beco e greater by increasing size of the zeolite. The surface areas of each size the zeolit size of 30, 60, and 90 mesh are 61.95, 110.14, and 226.15 m2/g, whereas acidi of each the zeolit size are 1.0283, 1.1132, and 1.7619. The protein contents in so ution before the adsorption is 1.74 mg/mL. The percentage of adsorped enzy e at the zeolite before washing for each size of 30, 60, and 90 mesh are 89 % 95 %, and 97 %. The activity of immobilized enzyme become greater by Mere sing size of the zeolite. The activity of immobilized enzyme for each size are 0. • 346, 0.7676, and 0.9665 mg/100mL.