ModiGen™ Strains

Diacetyl formation begins in fermenting beer when α-acetolactate (a precursor for amino acids valine and leucine) builds up in excess inside of yeast cells and is secreted. Once secreted into the beer, α-acetolactate slowly and spontaneously oxidatively decarboxylates to diacetyl. Once this  occurs, the cells must reuptake the  diacetyl, which is then slowly converted to acetoin and 2,3-butanediol.  

Once diacetyl formation occurs, reuptake and reduction to other less perceptible molecules is a slow process. As a result, the natural diacetyl reduction process is often the rate limiting step when transferring a beer from fermentation/conditioning to packaging, increasing tank residency time and lowering cold-side production efficiency. 

ModiGen™D strains are engineered to contain a gene that codes for alpha acetolactate decarboxylase (ALDC) enzyme expression inside the cell. ALDC directly reduces a portion of intracellular α-acetolactate to acetoin, ensuring α-acetolactate will not build up in excess and be secreted into the beer.  

Excessive ALDC production inside the cell above what is required to prevent α-acetolactate secretion may deplete the intracellular α-acetolactate levels to the point the cell cannot effectively produce the amino acids valine or leucine on their own.

Once fermentation is complete and cells no longer have access to a rich media (i.e. during flocculation,  harvesting and storage), inability to synthesize  certain amino acids may affect cell health and future performance. 

We’ve found it only takes a minimal amount of  ALDC production inside the cell to achieve effective diacetyl prevention. As a result of the  genetic engineering techniques employed to insert the ALDC gene, ModiGen™D strains have good control over the number of ALDC genes inserted into the yeast genome, and therefore the amount of enzyme produced. At the levels of ALDC ModiGen™D strains produce, we’ve shown these strains can prevent diacetyl production while not significantly impacting yeast health and repitchabilty.  

Currently, we offer 4 strains with ModiGen Defense technology: 

• WLPMD001 ModiGen™D California Ale Yeast®

• WLPMD066 ModiGen™D London Fog Ale Yeast®

• WLPMD830 ModiGen™D German Lager Yeast

• WLPMD4000 ModiGen™D TYB Vermont Ale Yeast

Yes, all ModiGen™D strains available maintain diacetyl levels well below threshold levels of 50 -100ppb. At most points during fermentation, diacetyl levels are held consistently below 15 ppb, even in heavily dry hopped beers (~2.2 lbs/barrel). As compared to each parent strain, the ModiGen™D strains perform exceptionally well with respect to maintaining low diacetyl levels.

Yes, at both bench scale and brewery scale, each ModiGen™D strain performs similarly to their parent strain with respect to fermentation kinetics and the character of the finished beer. 

Yes, you can repitch ModiGen™D strains as you have with the parent strains.  We’ve conducted serial growth, harvesting and repitching tests in house and shown that yeast diacetyl prevention and fermentation kinetics remain consistent through at least 50 generations (cell doublings).

No, we do not contractually limit the number of times a brewer can repitch ModiGen™D strains. In fact, you won’t have to sign any kind of contract or material transfer agreement! You can reuse the yeast as many times as your processes supports.

No, brewers will not be required to pay royalties on barrels of beer produced with ModiGen™D strains, regardless of brewery size.

No, breweries will not have to pay any licensing fees to access Modigen™D  strains. We do not employ any patented/licensed technology to create ModiGen strains, allowing us to eliminate these pass-through costs.

Yes, ALDC enzyme is safe. Recombinantly produced soluble ALDC is a process agent  commonly added to wort/beer, and has undergone extensive safety evaluation documented in GRAS filing GRN 587. In addition, ModiGen™D strains produce the ALDC enzyme intracellularly, resulting in most of the enzyme being removed with the yeast during flocculation/separation post-fermentation.

Yes, we take several steps to ensure the safety of ModiGen™D strains, including validation that antibiotic selection markers employed during the engineering process are removed in the final strain, and that no new unintended or harmful gene products are produced around the ALDC gene integration site. Other than the production of the ALDC enzyme, ModiGen™D strains are genetically identical to their parent strains.

Yes, due to strict regulations on GMOs in many countries, ModiGen™D strains are only currently available for sale and use in the United States.