Fig. 2

Simultaneous saccharification and fermentation (SSF) process schematic for cellulosic biofuel production. In both the a microcrystalline cellulose SSF (mcSSF) and b emulsified SSF (eSSF) processes, cellulase enzymes degrade cellulose into glucose, which is simultaneously metabolized by yeast into ethanol (or other chemicals). a In the mcSSF process, the untreated cellulose maintains a microcrystalline structure, which is more difficult for enzymes to hydrolyze. b In the eSSF process, the cellulose fibers coat the surface of oily droplets in the emulsion, providing better access to enzymes [45], and thus easier hydrolysis