SPOTLIGHT: Mobile Fermentation Unit Enhances Yeast Development Cycle

Using a plant’s mash in real time aims to de-risk and speed up pre-commercialization trials.
By FRANCOIS VAN ZYL | June 08, 2021

Developing new yeast strains can be challenging. What looks promising in the laboratory needs to be validated in the real world, but a full trial at an ethanol plant takes time—sometimes up to 10 weeks—and comes with risks. There’s a reason why we often get asked: “Who’s already run this before, we don’t want to be first.” The risk of a costly plant upset or a stuck fermentation is very real.

Aiming to de-risk yeast trials for cooperating ethanol producers while reducing the time required to introduce productive new yeast strains into the market, Lallemand Biofuels & Distilled Spirits continues its commitment to innovation by developing a new approach. We are proud to now introduce, the Mobile Application Process System, to the industry this summer at the International Fuel Ethanol Workshop & Expo. The mobile unit will be used to test yeast strains in research and development under real-world conditions at multiple plants.

Developing new yeast strains is a multi-step process. First comes idea generation and subsequent lab work that identifies promising new strains. Generally, we will need to run multiple experiments to confirm that the desired results will hold up without any unintended side effects. While we can try to mimic plant parameters in the laboratory or we can even take mash from a facility into the lab, it’s never a true representation of what goes on in fermentation in a commercial ethanol plant. The lab will never be able to replicate certain plant processes such as flow conditions, upsets or low-grade contaminants.

Once a strain passes the initial screening tests, the laboratory results need to be validated in real-world conditions. Some strains will be returned to the lab for more work while others will begin optimization—a phase that until MAPS could take weeks at a single plant and months when tested at several plants. With MAPS, we expect to cut that time at least in half, plus enable testing strains with other new technologies being deployed in the ethanol industry.

Housed in a 53-foot semi-trailer, MAPS is a self-contained fermentation unit complete with a propagation tank, six 300-gallon fermenters and a generator to run the agitators, instruments and distributed control system. The design, engineered and built by Nelson Baker Biotech, uses a plant’s mash flow to fill the system. Nelson Baker worked with Interstates to install the automation and DCS system.

Commissioned late last summer, we’ve been learning how to operate the system and duplicate the fermentation kinetics at our primary host plant, Absolute Energy, a 125 MMgy plant located on the Minnesota-Iowa border near Lyle, Minnesota. Parked near fermentation alley at the plant, lines connect the MAPS to the plant, receiving mash for propagation and eventually fermentation. Once fermentation is complete, the material gets pumped back into the beer well for downstream processing. MAPS can then be cleaned using the same connections from the plant.

MAPS is designed to not only use the host plant’s mash, which automatically exposes the yeast to the plant’s recycle streams, but also to mirror its cleaning regimen. We were pleased when our initial runs in MAPS matched up to the plant’s kinetics and HPLC results within 93%. As we’ve learned more about fine-tuning the system, we’re reaching 98% congruity.

Once we’ve validated the new yeast strain’s characteristics first identified in the laboratory, we can use MAPS to optimize other parameters such as yeast dosing, pH, nutrition, and temperatures to get to peak performance. Because it’s basically a mini fermentation system, we are able to test in real time other parameters that are hard to replicate in lab conditions, such as recycle streams, temperature and fusel tolerance; temperature staging and the ability to optimize enzyme additions.

Another advantage of MAPS is being able to run multiple parallel fermentations on the exact same mash under the exact same conditions as the plant. This creates a true apples-to-apples trial comparison, which would not really be possible without this system. This is as close to how things will run in the plant as you can currently get.

This new system allows us to cut the time required for commercial scale trials and to test our new yeast strains under a range of industry conditions and mashes. The system is designed to be mobile so it can be moved to other partnering ethanol producers representing different designs, process flows, fermentation times, recycle streams or different bolt-on technologies (such as protein extraction) being deployed in the industry. Because plants experience all sorts of fermentation challenges, we are now also able to test new strains instantly and remove those time-consuming validation steps. This really helps to increase confidence in a new strain’s performance.

MAPS is truly the first of its kind to be use in yeast development. We fully expect to partner with others in evaluating new technologies such as new inline measuring and analytical techniques and testing equipment that will give live results on fermentation. We also expect to use MAPS to validate other LBDS technologies that we are developing. 

“We’re looking forward to the new research and development taking place at Absolute, developing and deploying new strains for ourselves and the industry as a whole,” says Rick Schwarck, president and CEO of Absolute Energy. “And because the research and development is taking place on site, at an operating plant, putting the results in real-world use should happen faster and more efficiently than we’ve done in the past. It’s important for the health of the industry that we improve our efficiency and lower our carbon intensity as we move forward.”

Author: Francois van Zyl
Director of Technical Services-North America,
Lallemand Biofuels & Distilled Spirits
[email protected]

Published in July 2021 issue of Ethanol Producer Magazine