Integrated enzyme production lowers the cost of cellulosic ethanol

Previous studies of cellulosic‐ethanol production have shown that the cost of producing cellulase is surprisingly significant, and that reducing this cost is key to making cellulosic‐ethanol economically viable. This study confirms that finding, and compares the costs of the three approaches for producing cellulase: off‐site, on‐site, and integrated. It finds that the integrated method is the lowest cost, primarily because it substitutes an inexpensive feedstock, biomass, for a relatively expensive one, glucose. This substitution also makes the ethanol a 100% second‐generation biofuel, i.e., it uses no ‘food for fuel’. This study also compares the activity of cellulase produced by the integrated method versus that produced by the off‐site method. Laboratory trials of the two show the ‘integrated’ cellulase to be better or equal to commercially available ‘off‐site’ cellulase in converting cellulose to sugar.