Seleksi dan Formulasi Media Pertumbuhan Bakteri Penghasil Xilanase

Abstract

Seleksi bakreri penghasil xilanase dan formulasi media pertumbuhan bakteri penghasil xilanase telah dilakukan di laboratorium Bioproses, Balai Besar Penelitian dan Pengembangan Pascapanen Pcrtanian. Seleksi isolat bakteri dilakukan terhadap lima isolat penghasil xilanase yaitu RXAI-5, RXAII-5, RXAIII-1, RXAIII-5 dan RXNI-3), dengan membandingkan hasil kultivasi meliputi biomasa, protein terlarut, akrivitas xilanase dan aktivitas spesifik. Formulasi media dilakukan dengan mengoptimasi konsentrasi peptone, ekstrak khamir sebagai sumbcr nitrogen dan oat spelt xylane sebagai sumber karbon. Analisis percobaan menggunakan rancangan acak faktorial, faktor (A) peptone terdiri atas empat taraf yaitu A1=0, A2=0,I; A3=0,3; A4=0,5% Faktor (B) ekstrak khamir terdiri alas tiga taraf (B1=0,1; B2=0,2; B3=0,3%) dan faktor (C) oat spelt xylene terdiri atas tiga taraf (C1=0,5; C2=0,75; C3=1,0%) dengan tiga kali ulangan. Hasil penelitian menunjukkan bahwa isolat baktcri Bacillus pumilus RXAIII-5 dinyatakan sebagai isolat bakteri unggul diantara kelima isolat bakteri penghasil xilanase. Pada formulasi media ternyata protein terlarut tertinggi (0,596 g/l) pada media dengan komposisi 0,75% xilan, pepton 0,5%, ekstrak khamir 0.2%. Aktiviras xilanase dan aktivitas spesifik tertinggi berturut-turut adalah 186,37 u/ml dan 436,45 U/mg protein. Keduanya dicapai pada komposisi media yang sama yaitu pepton 0, 1 %, ekstrak khamir 0, I %, dan xilan 0,5%. Dcngan demikian komposisi tersebut merupakun komposisi mcdi a terpilih yang optimum. Isolat bakteri unggul bersifat alkali ini diharapkan dapar menghasilkan xilanase yang tahan pada pH tinggi sehingga dapat digunakan untuk proses pemutihan kertas yang ramah lingkungan. Selection and Growth Medium-Formulation of Xylanase Producing BacteriumThis research was carried out in the bioprocess laboratory of Indonesian Center for Agricultural Postharvest Research and Development, Bogor. Selection of five isolates (RXAI-5, RXAII-5. RXAIII-1, RXAIII-5 and RXNI-3). xylanase producing bacteria Were based on comparative study of cultivation yield consists of biomass of bacterium cells, dissolved protein, xylanase activity and specific activity, Formulation of growth medium using peptone and yeast extract as nitrogen source and oat spclt xylan as carbon source. Design experiment used at formulation of growth medium was randomized factorial design. with factor A) peptone consist of four level, A 1=0. A2=0.1; A3=0.3; A4=0.5%, factor (8) yeast extract consist or third level (131=0.1, 132=0.2; 133=0.3%) and factor (C) oat spelt xylan consist of three level (CI=0.5; C2=0.7S; C3=1.0%), with three replication. Research result showed that Bacillus pumilus RXAIII-5 is the best bacterium isolate among five isolates of xylanase producing bacteria. In growth medium formulation showed that highest dissolved protein (0.596 g/l) was achieved in the medium containing 0.75% xylan, 0.5% pepton, and 0.2% yeast extract. The highest value of both of xylanase activity and specific activity are 186.37 u/ml and 436.45 U/ml respectivelly. In fact these were reached at similar growth medium composition of 0.1 % pepton, 0.1 % yeast extract, and 0.5% xylan, and consequently became the best of growth media formulation. The potential alcaliphilic bacterial isolate is expected to produce xylanase with high pH stability. The enzyme can be used as environmentaly safe agent for paper bleaching