The design, construction, and operation of a pilot-plant unit to convert waste sugarcane bagasse into microbial single-cell protein by a previously developed process is described. After the bagasse was ground and given a milk alkaline oxidation treatment it was fermented on a continuous-flow basis by Cellulomonas, sp bacteria, and also by a mixed culture run of Cellulomonas and the symbiotic organism Alealigenea faecalis. Maximum cell density obtained with pure Cellulomonas was 1.7 g dry weight per liter and 6.24 g per liter for the mixed culture. Culture mass-doubling times during log-phase growth were usually from 3.2 to 3.7 hr. The maximum experimental volumetric production efficiency of a continuous run using pure Cellulomonas was about 0.10 g of dry cell mass per liter of fermenter capacity per hr. The single-cell protein, produced as a light brown to yellow-brown powder, has a crude protein content of 50 to 55 percent. (Author)