Abstract

Rice bran (RB) was used as a medium for the fermentation process because it contained complete nutrients necessary for the growth of microbes. The ability to induce a fermentation substrate by microbes dependent on the availability of an inducer in the medium. The enzyme activity would increase when a suitable inducer was in the medium. In order to increase protease and cellulase activities of Rhizopus oligosporus in processing Cassava Leaf Meal (CLM), it was necessary to add CLM in medium producing an inoculum Rhizopus oligosporus. This study was conducted in a completely randomized design with 4 treatments and 5 replications. The treatments were ratios of RB to CLM as follows: 100:0% (A), 90:10% (B), 80:20% (C), and 70:30% (D). The observed variables were protease activity, cellulase activity, dry matter content, organic matter content and the total colony of Rhizopus oligosporus numerically. The different ratios of RB to CLM significantly affected protease and cellulase activities as well as the content of dry matter and organic matter. The addition of 10% CLM to the RB medium increased protease and cellulase activities and reduced dry matter and organic matter contents. However, when more than 10% CLM was added, it reduced the protease and cellulase activities and increased dry matter and organic matter content. The highest total colony of Rhizopus oligosporus was numerically in treatment B (90:10% of RB to CLM ratio). The appropriate ratio of RB to CLM mixture as the inoculum of Rhizopus oligosporus, based on their enzyme activities, dry matter, and organic matter contents, and the total colony was 90:10% (treatment B).