Patent ID: 7504245

Claim:
A method comprising: applying ultrasonic energy to a liquid medium processing stream in a cellulose-to-ethanol production process, wherein the liquid medium processing stream contains switch grass comprised of cellulose surrounded by a protective sheath of hemicellulose and lignin, wherein the ultrasonic energy is applied at one or more locations prior to fermentation, or before and after fermentation, with one or more high-powered transducers, each generating at least 3 kW of power and operating at a frequency of at least 17 kHz, wherein the power and frequency of the ultrasonic energy are sufficient to produce cavitational forces in the processing stream at an intensity and duration which causes at least a portion of the lignin to be loosened or removed from the cellulose, allowing an increased amount of cellulose to be hydrolyzed into one or more individual component sugars, wherein conversion of the one or more individual component sugars to one or more fermented individual component sugars during fermentation is increased; and distilling and dehydrating the one or more fermented individual component sugars to produce ethanol and residuals, wherein ethanol yield is increased by applying the ultrasonic energy.