Produksi Gula Reduksi oleh Rhizopus oryzae dari Substrat Bekatul

Rice bran was produced from rice-hulling process. Rice bran was contain high starch, therefore it was used to saccharification process. The aim of this research was to study the optimum concentration of rice bran to produce reducing sugar on saccharification process by Rhizopus oryzae. The 100 mL-rice bran medium (5, 10, 15, 20, 25, and 30%) were sterilized at 1210C, for 15 minutes and inoculated with R. oryzae (± 2x106 cfu) and incubated for 3 days. The concentration of reducing sugar, starch, pH value, and biomass were analyzed everyday. Concentration of starch was decreasing during saccharification process. However, the concentration of reducing sugar was maximum at first day saccharification. The optimum concentration of rice bran for saccharification process was showed by maximum production of reducing sugar (15,347 mg/mL); it was in 20% concentration of medium. The pH value was decreasing during saccharification process, and the biomass was reversed. Keywords: rice brans, Rhizopus oryzae, saccharification, reducing sugar.