The effects of fermentation of cassava by Aspergillus niger B-1 beta-glucosidase on its cyanide and protein content, and the optimal conditions for this enzyme’s activity, were examined, This fermentation process reduced the cyanide content of cassava by 95% to 2 mg/kg, and increased its total protein content by 50%, thereby improving its nutritional value, A significant decrease in cyanogenic glycosides was detected after 3 days of fermentation. The optimal pH for A. niger beta-glucosidase activity on the cyanogenic glycoside linamarin was determined to be 3, the optimal temperature 55 degrees C, and its K-m 0.3 mM. The findings presented here will facilitate the development of an improved method for detoxification of cassava and for enhancement of its nutritional value.