A New Proposal of Cellulosic Ethanol to Boost Sugarcanetests described so far involve the ethanol-sensitive lab strain of yeast. “ethanol tolerance is one of those traits that’s sort of mysterious,” says lam. researchers already have pushed up ethanol productivity from the levels reported here. “butanol, for example, has a higher energy content per liter; and unlike ethanol, it can be used as a direct substitute for gasoline in today’s cars. in other “firsts,” the researchers described the mechanism by which alcohols poison yeast; they defined two genes that control ethanol tolerance; and they modified those genes in lab yeast to make them out-produce the industrial strains—even without the supplements.
Ethanol Production From Mixed Waste Paperbut yeast strains used commercially are carefully selected for their genetic predisposition toward ethanol tolerance. “altering a single gene has not prevented diabetes—or made yeast more ethanol-tolerant. of optimum fuel ethanol production system for the use of bagasse and straws. examination showed that the elevated potassium plus reduced acidity results in an increase in cell viability and thus in ethanol productivity. but the boost in ethanol production persisted even when they used genetic methods to disable phosphate metabolism in the yeast.
but there’s a problem: at certain concentrations, the ethanol kills the yeast that make it. each supplement pushed up ethanol output significantly, and adding the two together brought an increase of 80%. engineers and biologists at mit have found a simple way to make yeast produce more ethanol from sugars: spike the mixture they’re growing on with two common chemicals. in addition, assisting the commercial strains with the supplements pushes their ethanol yields up to roughly the same level as yields from the lab strain with supplements. not surprisingly, the baseline ethanol production from those strains is higher than that from the basic lab strain.
” at concentrations achieved in biofuel production, alcohols do not dissolve the yeast’s cell membrane but rather make it porous. challenge is to make fuels that are better suited than ethanol to today’s transportation needs. “everyone knows that ethanol is ultimately a pretty lousy fuel,” says lam. if larger-scale laboratory or pilot-plant tests take place and are successful, lam notes that it should be relatively easy to implement the approach at existing bioethanol plants: just increase potassium levels and control acidity inside the bioreactor. curves show ethanol production from laboratory yeast growing on glucose for 72 hours.