SIFAT FISIKOKIMIAWI SELULOSA PRODUKSI ISOLAT BAKTERI Gluconacetobacter xylinus KRE-65 PADA METODE FERMENTASI BERBEDA (Physicochemical Properties of Cellulose Produced by Bacterial Isolate Gluconacetobacter xylinus KRE-65 in Different Fermentation Methods)

Physicochemical properties of cellulose produced by local bacterial strain Gluconacetobacter xylinus KRE-65 by static and agitated fermentation methods was studied. Cellulose production by G. xylinus KRE-65 was carried out in coconut base medium with static and agitated fermentation methods. The dry weight, morphological and physicochemicalproperties of bacterial cellulose were compared based on SEM, XRD and FTIR analyses. The results showed that the G. xylinus KRE 65 in the static fermentation produced cellulose higher than agitated fermentation. Static fermentation method produced bacterial cellulose in the sheets form, while agitated fermentation produced fragmented cellulose with predominantly spherical shape. The observation of the surface structure of bacterial cellulose by SEM showed that the static fermentation method generated woven densely cellulose microfibrils, while agitated fermentation significantly changed the surface structure, namely woven microfibrils become more loose with formed larger and higher number of pores. The degree of crystallinity of bacterial cellulose by XRD analysis in static fermentation was 91%, agitated fermentation at 100 rpm was 73% and agitated fermentation at 150 rpm was 72%. FTIR spectra indicated that the pellicles produced by G. xylinus KRE 65 with static and agitated fermentation were found as cellulose. Cellulose produced from both fermentation methods showed different physicochemical properties, therefore they can be applied for different purposes in accordingly.Keywords: Gluconacetobacter xylinus, bacterial cellulose, static fermentation, agitated fermentation ABSTRAKSifat fisikokimiawi selulosa yang dihasilkan oleh strain lokal bakteri Gluconacetobacter xylinus KRE-65 dengan metode fermentasi statis dan agitatif telah diteliti. Produksi selulosa oleh G. xylinus KRE-65 dilakukan dalam media dasar air kelapa dengan metode fermentasi statis dan agitatif. Selulosa yang dihasilkan selanjutnya dibandingkan beratkering, bentuk morfologi dan sifat fisikokimiawinya menggunakan metode SEM, XRD dan FTIR. Hasil penelitian menunjukkan bahwa G. xylinus KRE 65 menghasilkan selulosa lebih tinggi pada metode fermentasi statis dibandingkan fermentasi agitatif. Metode fermentasi statis menghasilkan selulosa bakteri yang berbentuk lembaran sedangkan fermentasi agitatif menghasilkan selulosa yang terpecah-pecah dengan bentuk dominan bulat. Pengamatan struktur permukaan selulosa bakteri dengan SEM memperlihatkan bahwa metode ferm