18-03: An alternative approach for making 2nd generation bioethanol viable

The yeast Saccharomyces cerevisiae has been used for over 4,000 years to produce leavened bread, beer, wine, and more recently fuel ethanol, feed, flavors, vitamins and nutraceuticals.  This species is remarkable in that it has the dual ability to rapidly ferment six-carbon sugars in molasses, starch syrups and fruit juices, whilst also being able to respire these sugars and certain non-fermentable carbon compounds to produce yeast biomass.  In fact, over 2.5 million tons of yeasts are produced per annum using, mostly, molasses or starch syrups, but the manufacture of yeast has to compete increasingly with the expanding first generation fuel ethanol industry for these substrates.  Therefore, alternative carbon sources need to be found for the sustainable production of Saccharomyces.  

Microbiogen has bred non-recombinant strains of S. cerevisiae that grow in lignocellulosic hydrolyzates to produce food-grade yeasts worth 14c to over $5 per lb, depending on their application. These yeast strains ferment cellulose-derived sugars into ethanol as effectively as current commercially available corn-ethanol yeast strains and have the added ability to aerobically convert xylose, ethanol, glycerol and acetate into yeast biomass. Such characteristics open up the possibility of using lignocellulose as a substrate for yeast manufacture as well as for ethanol production in food and fuel biorefinery processes, with the potential for second generation ethanol producers to tap into other yeast applications worth over US$100 billion per annum.  This approach would have a major positive impact on the economics of 2^nd Generation Bioethanol.