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Title: CHARACTERIZATION OF A NOVEL ETHANOLOGENIC YEAST IN THE FERMENTATION OF SOFTWOOD LIGNOCELLULOSIC SUGARS

Author
item KEATING, J - UNIV BRITISH COLUMBIA
item ROBINSON, J - UNIV BRITISH COLUMBIA
item Bothast, Rodney
item SADDLER, J - UNIV BRITISH COLUMBIA
item MANSFIELD, S - UNIV BRITISH COLUMBIA

Submitted to: Biotechnology for Fuels and Chemicals Symposium Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2002
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: A novel, genetically unmodified ethanologenic yeast, integrated into the pre-hydrolysate fermentation stage of the softwood-to-ethanol bioconversion process, was identified as being capable of rapid assimilation and catabolism of all wood-derived hexose sugars (galactose, glucose, and mannose). This yeast strain was shown not to be subject to glucose-mediated catabolite repression and to employ a unique enzymatic mechanism to immediately and concomitantly convert galactose, glucose, and mannose to ethanol within 8 hours on synthetic sugar media and 18 hours on steam-exploded softwood pre-hydrolysate. Regardless of substrate conditions, the selected yeast strain immediately initiated galactose metabolism at the onset of fermentation, demonstrating complete consumption of the sugar alongside that of glucose and mannose. The conventional sequential sugar utilization observed in most ethanologenic yeasts consistent with preferential cell membrane transport and catabolism was notably absent, as was the conventional slow rate of galactose consumption. Ethanol yields were comparable with those achieved by current industrially utilized yeast strains. The unique enzyme found in this yeast strain aided hexose sugar catabolism through rapid activity and specific localization.