Monday, April 19, 2010: 3:30 PM
Salon A-E (Hilton Clearwater Beach)
Industrial strains of the yeast S. cerevisiae are widely used for large scale production of fuel ethanol. However, generally they are not genetically tractable and cannot utilize cellulose. We constructed a genetically manipulable industrial S. cerevisiae strain. This strain can be easily transformed with exogenous DNA, exists as stable haploids of both mating types, efficiently mates and forms viable diploids. Diploids have very high sporulation efficiency and produce viable spores. This strain has high tolerance to alcohol, a large range of fermentation temperatures and grows rapidly to high cell density. Several cellulase genes from different families were integrated into the genome of this strain. High-throughput screening of several thousand integrants allowed identification of strains with the highest cellulolytic activities. These strains produce ethanol in one step from different types of biomass (corn cob, newspaper, Whatman paper, paper sludge) without addition of external cellulases. These cellulolytic yeast strains ferment pretreated cellulose to ethanol with yields of 65% of theoretical in 48 hours.