Sunday, May 3, 2009
2-35
Rapid fermentation of glucose, xylose and cellobiose by the wood-boring beetle-associated yeast, Spathaspora passalidarum
Tanya M. Long, Great Lakes Bioenergy Research Center, One Gifford Pinchot Drive, Madison, WI 53726, Jennifer R. Headman Van Vleet, EdeniQ, 1520 N. Kelsey St., Visalia, CA 93291-9255, Michael A. Caballero, UW-Madison, One Gifford Pinchot Drive, Madison, WI 53726, and Thomas W. Jeffries, Forest Products Laboratory, USDA Forest Service, One Gifford Pinchot Drive, Madison, WI 53726-2398.
The efficient fermentation of xylose and cellobiose is one of several significant challenges in the bioconversion of lignocellulosic hydrolysates to fuel ethanol. These sugars comprise the majority of a plant cell wall; however most fermentative yeasts are unable to use them. Recently, Nguyen, et al. (2006) described a novel ascomycetous yeast, Spathaspora passalidarum, isolated from the gut of the beetle, Odontotaenius disjunctus. This insect is commonly found in decaying logs; therefore organisms located in its gut would be exposed to carbon sources commonly found in lignocellulosic hydrolysates.
Here we describe the growth and fermentation characteristics of this yeast when cultivated on multiple carbon sources, including glucose, xylose, or cellobiose. Initial experiments indicate that it exhibits a distinctly different growth potential from previously characterized species when cultivated in medium with xylose or cellobiose as sole carbon sources, and shows excellent growth potential when grown on all of above sugars. Significant ethanol production was observed under oxygen limitation, and its capacity for growth under severe oxygen limitation exceeded that of other native xylose fermenting yeasts. Initial observations indicate that this yeast may even surpass Pichia stipitis in its ability to ferment xylose. Further characterization of S. passalidarum will provide great insight into native mechanisms of lignocellulose degradation and fermentation by microbes.
Nguyen N, Suh S, Marshall C, Blackwell M, 2006. Morphological and ecological similarities: Wood-boring beetles associated with novel xylose-fermenting yeasts, Spathaspora passalidarum sp. nov. and Candida jefftriesii sp. nov. Mycol. Res. 110:1232-1241.
Here we describe the growth and fermentation characteristics of this yeast when cultivated on multiple carbon sources, including glucose, xylose, or cellobiose. Initial experiments indicate that it exhibits a distinctly different growth potential from previously characterized species when cultivated in medium with xylose or cellobiose as sole carbon sources, and shows excellent growth potential when grown on all of above sugars. Significant ethanol production was observed under oxygen limitation, and its capacity for growth under severe oxygen limitation exceeded that of other native xylose fermenting yeasts. Initial observations indicate that this yeast may even surpass Pichia stipitis in its ability to ferment xylose. Further characterization of S. passalidarum will provide great insight into native mechanisms of lignocellulose degradation and fermentation by microbes.
Nguyen N, Suh S, Marshall C, Blackwell M, 2006. Morphological and ecological similarities: Wood-boring beetles associated with novel xylose-fermenting yeasts, Spathaspora passalidarum sp. nov. and Candida jefftriesii sp. nov. Mycol. Res. 110:1232-1241.