Produksi Selulase Dari Bacillus pumilus GOR2 Isolat Asal Saluran Pencernaan Larva Kumbang Badak (Oryctes rhinoceros) Menggunakan Substrat Jerami Padi

CELLULASE PRODUCTION BY Bacillus pumilus GOR2 ISOLATED FROM DIGESTION TRACT OF KUMBANG BADAK LARVAE (Oryctes rhinoceros) USING RICE STRAW SUBSTRATE Elza Giovanni Yemima Depthios Biology Study Programme, Faculty of Mathematics and Natural Sciences Sebelas Maret University, Surakarta ABSTRACT One of the renewable energy that is currently being studied is bioethanol. An important stage of bioethanol production is lignocellulosic hydrolysis. Rice straw is one of agricultural wastes containing lignocellulose that can be used as a substrate for microorganism in enzymatic lignocellulosic hydrolysis process. The aim of this research is to know the optimum of carbon source concentration, pH and temperature for cellulase enzyme production of bacteria isolate of Bacillus pumilus GOR2 by using rice straw substrate, and to know cellulase productivity produced at optimum substrate concentration, pH and temperature. Pretreatment/delignification of rice straw using a 6% NaOH concentration solution with a ratio of 1: 5. The composition of the enzyme production medium (100 ml) was 0.2 g , 0.05 g , 0.005 g , 0.001 g , 0.002 g , 0.0002 g , 0.05 g yeast exstract, and rice straw as substrate. The variation of rice straw substrate concentration using is (in b / v) l%; 2%; 3%; 4%. The pH variations using is 3, 5, 7, and 9. The temperature variations using is 30°, 40°, 50°, 60° C. The cellulase activity is determine by the DNS (Dinitrosalicylic Acid) method using CMC (Carboxy Methyl Cellulase) substrate. Measurement of dissolved protein content using Bradford method. The results showed that the production of Bacillus pumilus GOR2 cellulase was optimum at 4% of rice straw substrate concentration, pH 3, and 30%. The resulting specific cellulase activity was 5.67 U/mg protein, with cellulose productivity 0,2268 U/g rice straw powder. Keywords : rice straw, cellulase, bacteria, substrate concentration, temperature, pH