Written by GABE TOTH /// Images provided by Lallemand
GENETIC Exploring advancements in engineered microorganisms for spirits production
ENGINEERING T
he realm of engineered microorganisms — organisms whose genomes have been modified in a laboratory in order to favor the expression of desired physiological traits — is a rapidly advancing field that affects beverage alcohol production. Used in a variety of consumer goods, such as fuel ethanol, pharmaceuticals, and foodstuffs, the future of this field holds many opportunities for the distilling industry and beyond. With this in mind, Artisan Spirit has worked alongside Lallemand — a global presence in the industries noted above — studying internal documents and intra-industry presentations, interviewing team members who represent the company’s diverse range of interests, and assembling a broader perspective on the past, present, and potential future of genetic engineering in the microbial world.
WHAT IS YEAST?
Yeast is one of the primary flavor drivers in spirits production and arguably the flavor driver for beer. Those who wish to debate the point should start by tasting an unfermented wash or wort and then a fermented one. Humans have used yeast for millennia, but it wasn’t observed under a microscope until 1680 by Antonie van Leeuwenhoek, an early Dutch microbiologist who didn't consider yeast as a living thing. Yeast has since been used as a model organism offering insights into how other organisms work. 54
Jumping ahead to modern time, in 1996, Saccharomyces cerivisiae was the first eukaryotic genome to be sequenced, making it a ripe target for ongoing research and development, though most or all of the engineered yeasts mentioned later in the article did not reach the plant-scale research phase or become commercially available. Genetically modified yeasts date back to 1994, when a brewing yeast containing a glucoamylase gene and copper resistance was approved in the United Kingdom. (It could be argued that genetically modified S. cerevisiae has been on the market since the 1980s, when insulin produced by bioengineered yeast was approved for usage.) In 2001, a self-cloned sake yeast that offered increased levels of ethyl caproate at the lab scale was approved in Japan. In 2003 (United States) and 2006 (Canada) an R&D wine strain was approved that contained a malate transport gene and a malolactic gene to eliminate malolactic processing time. In 2006 an R&D wine yeast was engineered to reduce production of ethyl carbamate, a known carcinogen currently being targeted by malting barley breeders, and another wine strain was approved in 2011 for reduced hydrogen sulfide production. Seibel1 reported that a lab team had created a yeast strain appropriate for lower-alcohol production, shifting some of the carbon
IN THE DISTILLING INDUSTRY
flux toward glycerol production and away from ethanol. The same paper mentions the saturation of the beer market and the increased demand for new yeast-driven flavors, with researchers developing a yeast capable of producing monoterpenes to increase hoppy notes in the finished beer. Key compounds in hop character include linalool and geraniol, which are synthesized from geranyl pyrophosphate via monoterpene synthase. The researchers theorized that by adding monoterpene synthases into brewer’s yeast using current genetic-engineering technology, they could increase the yeast's natural, but limited, ability to create linalool and geraniol. “Created strains were tested in a fermentation which was analyzed via LC/MS, HPLC and GC/MS. A taste panel evaluated the beer produced by the optimized strains and determined a range of hop flavors. [They] concluded, that yeast-built monoterpenes give rise to hop flavor in the finished beer and provide more consistency than traditional hopping.”1 Researchers have been able to modulate various yeast-produced flavors in the lab
Yeast is one of the primary flavor drivers in spirits production and arguably the flavor driver for beer. W W W . ARTISANSPIRITMAG . C O M