31. Investigation of Lachancea thermotolerans as a novel, single-strain brewing yeast

Claire Svendsen (1), John Sheppard (1); (1) North Carolina State University, Raleigh, U.S.A.

Technical Session 9: Brewing Microbiology
Monday, August 15  •  9:45–11:30 a.m.
Plaza Building, Concourse Level, Governor’s Square 14

Isolated and propagated at North Carolina State University, a novel strain of yeast, Lachancea thermotolerans NCSU, has been investigated for its application as a single-strain brewing yeast. Beer is primarily brewed with yeast of the genus Saccharomyces. Generally, other yeasts are considered spoilage organisms in beer; however, a few have been noted for their usefulness in brewing. These other accepted brewing yeasts are typically co-fermented with a Saccharomyces yeast, due to the inability to produce sufficient ethanol and/or the production of off-flavors (e.g., Brettanomyces). L. thermotolerans NCSU has proven to be a viable brewing yeast in laboratory and pilot-scale fermentations, as it fermented the principal wort sugars (i.e., maltose and maltotriose) while producing CO2, ethanol, glycerol, and lactic acid. In a pilot-plant scale fermentation of lambic-style wort (malted barley and wheat, OG 1.057), L. thermotolerans NCSU was able to produce 6.8% ABV and reduce the pH to 3.60 (FG 1.005). Furthermore, L. thermotolerans NCSU showed improved fermentation ability in comparison to type strain NRRL Y-8284 (ATCC 56472) in an all-barley malt (OG 1.053); differences included FG (1.016 vs. 1.041), increased maltose utilization (Delta 61.4 g/L vs. Delta 3.5 g/L), ethanol production (4.15% vs. 1.06% ABV) and pH reduction (3.65 vs. 4.87). This demonstrated L. thermotolerans NCSU as a unique strain, and more fit as a brewing yeast compared to NRRL Y-8284. The capability to produce beer with L. thermotolerans NCSU will provide brewers with an alternative to Saccharomyces for creating innovative beer styles and flavors using a single strain of yeast. With its ability to produce lactic acid, novel sour beers can be created without the risk of bringing bacteria or other “contaminant” yeasts into the brewhouse.

Claire Ingrid Svendsen was born in San Jose, CA, and now resides in Raleigh, NC. Claire first joined North Carolina State University (NCSU) and the Department of Food, Bioprocessing and Nutrition Sciences as an undergraduate student. She graduated in December 2012, with a B.S. degree in food science and a minor in agricultural business management. After graduation, Claire interned at NCSU in the Biomanufacturing Training and Education Center (BTEC) analytical laboratory under the direction of Dr. Nathaniel Hentz. Claire began her master’s degree studies in the fall of 2013, majoring in food science and minoring in biomanufacturing, under the guidance of Dr. John Sheppard. During that time, she served as a teaching assistant, research assistant, and also worked in the NC State brewery. She was active in the Food Science Club and served on the executive board from 2014 to 2015. At the Institute of Food Technologist (IFT) national conference in 2015, Claire, as part of a three-person development team, was awarded first place in the Dairy Research Institute Product Development Competition for creating a “Shake and Go-Kefir,” a fruit-on-the-bottom fermented dairy beverage.