Developing low-intensity pulsed ultrasound circuits to enhance cellulosic bioethanol yield for renewable energy
As the world finite supply of fossil fuels diminishes, viable alternatives are needed to empower the transportation, heating, and industrial needs of modern civilization. Lignocellulosic ethanol promises a means to transform abundant plant wastes into an energy-dense, carbon-neutral liquid combustible, compatible with current infrastructure. Unlike the first-generation biofuels derived from corn or sugarcane, lignocellulosic ethanol does not infringe on food production, although extra steps are needed to convert bulk cellulose into simple sugars suitable for fermentation. In order for lignocellulosic bioethanol production to become economically viable, a number of breakthroughs are needed at each individual step. A major constraint for cellulose hydrolysis is the cost of cellulase enzymes, which can account for 30–50% of total production costs. With this problem in mind, we propose to enhance the production and function of cellulase enzymes through the application of low-intensity pulsed ultrasound (LIPUS), making the conversion of lignocellulosic biomass into bio-ethanol a more economical process. Our bench studies have shown that LIPUS could enhance enzyme production in liquid cultures of Trichoderma Reesei, a cellulase enzyme producing fungi, by 50%. Further studies have shown that LIPUS applied to cultures of Saccharomyces Cerevisiae can increase the conversion rate of glucose to ethanol.