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United States Department of Agriculture

Agricultural Research Service

Research Project: IMPROVING BIOCHEMICAL PROCESSES FOR THE PRODUCTION OF SUSTAINABLE FUELS AND CHEMICALS

Location: Renewable Product Technology Research Unit

Title: Random UV-C mutagenesis of Scheffersomyces (formerly Pichia) stipitis NRRL Y-7124 to improve anaerobic growth on lignocellulosic sugars

Authors
item Hughes, Stephen
item Bischoff, Kenneth
item Gibbons, William -
item Bang, Sookie -
item Pinkelman, Rebecca -
item Slininger, Patricia
item Qureshi, Nasib
item Liu, Siqing
item Saha, Badal
item Jackson, John -
item Cotta, Michael
item Rich, Joseph
item Javers, Jeremy -

Submitted to: Journal of Industrial Microbiology and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 15, 2011
Publication Date: January 1, 2012
Repository URL: http://handle.nal.usda.gov/10113/54031
Citation: Hughes, S.R., Bischoff, K.M., Gibbons, W.R., Bang, S.S., Pinkelman, R., Slininger, P.J., Qureshi, N., Liu, S., Saha, B.C., Jackson, J.S., Cotta, M.A., Rich, J.O., Javers, J. 2012. Random UV-C mutagenesis of Scheffersomyces (formerly Pichia) stipitis NRRL Y-7124 to improve anaerobic growth on lignocellulosic sugars. Journal of Industrial Microbiology and Biotechnology. 39(1):163–173.

Interpretive Summary: Yeast strains for anaerobic conversion of five- and six-carbon sugars to ethanol were produced from Scheffersomyces (formerly Pichia) stipitis NRRL Y-7124 by using UV-C irradiation that produced mutations in the genome and generate unique strains. The irradiated strains were capable of growing anaerobically on xylose plus glucose as the carbon sources with higher ethanol production than a Saccharomyces cerevisiae yeast strain during 250 to 500-hour growth. These new strains have potential application in industrial high-yield fuel ethanol production from plant biomass.

Technical Abstract: Yeast strains for anaerobic conversion of lignocellulosic sugars to ethanol were produced from Scheffersomyces (formerly Pichia) stipitis NRRL Y-7124 using UV-C mutagenesis. Random UV-C mutagenesis potentially produces large numbers of mutations broadly and uniformly over the whole genome to generate unique strains. Wild-type cultures of S. stipitis NRRL Y-7124 were subjected to 4-hour irradiation with UV-C (234 nm) targeted to kill approximately 60% of cells. When surviving cells were selected in sufficient numbers via automated plating strategies and cultured anaerobically on xylose medium for 5 months at 28 deg C, five novel mutagenized S. stipitis strains were obtained. It was determined using variable number tandem repeat (VNTR) analysis that mutations had occurred in the genome, which may have produced genes that allowed the anaerobic utilization of xylose. The mutagenized strains were capable of growing anaerobically on xylose/glucose substrate with higher ethanol production than a Saccharomyces cerevisiae yeast strain during 250 to 500-hour growth. The Scheffersomyces stipitis strains resulting from this intense multigene mutagenesis strategy have potential application in industrial high-yield fuel ethanol production anaerobically for fermentation of lignocellulosic hydrolysates.

Last Modified: 4/20/2014
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