Revista de biorremediación y biodegradación

Abstracto

Production of Ethanol from High Dry Matter of Pretreated Loblolly Pine by an Evolved Strain of Saccharomyces Cerevisiae

Gary Matthew Hawkins, Debashis Ghose, Jordan Russel and Joy Doran-Peterson

Obtaining the highest possible yields from a batch fermentation process is desirable for a cellulosic ethanol facility, as this leads to greater profitability by increasing distillation efficiency and reducing costs. One way to increase yields is by increasing the percentage of solids fermented in a batch process which leads to increased fermentable sugars available and thus increased theoretical maximum yields. One factor limiting the solids loading is that during biomass pretreatment a number of inhibitory compounds are released. These confound the fermentation process in a variety of ways, and as the solids concentration increases so do the concentrations of these inhibitors. There for ea biocatalytic strain that is able to ferment high concentrations of pretreated biomass and withstand the inhibitors present in the fermentation media is desirable. Pine wood has proven to be a particularly difficult biomass type from which to obtain high ethanol titers when fermenting concentrations of solids much greater than 10% dry weight. We previously described a strain of Saccharomyces cerevisiae, AJP50, which is able to ferment high concentrations (17.5% dry wt/v) of sulfur dioxide steam exploded pine wood. Present research details the performance of four isolates of AJP50 and their ability to produce ethanol from pretreated pine. We report ethanol yields of over 50 g/l (91% of maximum theoretical yield) from 22.5% dry wt/v of pine fermented using a simultaneous saccharification and fermentation process with strain GHP4 as the biocatalyst.