CONVERSION OF RICE STRAW TO HIGH-PROTEIN ANIMAL FEED BY DISCONTINUOUSGRADIENT FED-BATCH FERMENTATION

Discontinuous gradient fed-batch fermentation by Cellulomonas flavigen a on rice straw suspended in a simplified mineral medium was achieved and the microbial cells analyzed for nutrient composition and in vitro digestibility. The rate of bacterial growth yield constants and produ ctivity decreased following two- and four-fold increases in the concen tration of the medium. After 32 h a final yield of 13.7 g cells dm-(3) was obtained and 70.25% of the rice straw was solubilized. Up to 25.3 4% of the total substrate weight that had been solubilized was recover ed as bacterial protein. The protein content of the recovered material was 52%, and 10 essential and 9 non-essential amino acids were identi fied; the in vitro digestibility of bacterial protein was 50.8%.