The Next Step

Lallemand Biofuels & Distilled Spirits’ new Convergence platform merges its expertise in yield enhancement and enzyme expression. Other innovators have similar goals.
By Lisa Gibson | December 22, 2020

Lallemand Biofuels & Distilled Spirits has released what company President Angus Ballard says is an enormous “step change” in the ethanol production process, on par with the emergence of genetically modified yeast. LBDS’ Convergence platform marries its work in yield-enhancing yeast with glucoamylase production to provide optimal performance. TransFerm CV5 and Alcolase 146 work together to greatly reduce exogenous GA requirements, as well as enhance yield.

To date, yeast innovation has moved forward with “a little more yield, a little more robustness, a little more GA expression,” Ballard says. “Until now.”

“We have a technology now that the yeast can express levels of GA that literally were thought impossible. It’s literally a step change in the amount of exogenous GA required. Instead of needing truckloads of GA, it’s a small amount, it’s a tote of 1,000 liters that will last several weeks.
“That’s the exciting change.”

Complementary Combination

Convergence is a combination of an external enzyme package, Alcolase 146, that complements the TransFerm CV5 yeast, with its yield-enhancing features and enzyme expression, says Matt Richards, director of application technology for LBDS. It’s the first time LBDS has been able to demonstrate such a significant level of yeast-produced enzyme in the ethanol production process, he adds.

“We’ve seen roughly 70% to complete displacement of the added enzyme in fermentation being provided by the yeast in the process,” Richards says.

“The exciting part is the displacement of the GA,” he adds. “The yeast produces both the GA and trehalase, so when coupled with Alcolase 146, we get the best performance. But in some cases, we have demonstrated complete replacement of a GA package with the yeast-made enzymes.”

Before Convergence, conventional dry yeasts from LBDS with a complete exogenous enzyme package were able to replace 25% to 45% of enzyme needs. “This is obviously a significant increase to that,” Richards says.
GA works to break down the solubilized longer chain soluble starches, dextrins, into glucose for the yeast to ferment directly. “GA is really what needs to work to make sugars available to yeast for fermentation,” Richards says.

Trehalase splits the trehalose made by the yeast in fermentation. Without splitting, trehalose tends to build up and recycle in fermentation.

“Yeast can displace more of the overall cocktail by expressing more of the trehalase and glucoamylase, the two most important enzymes for the yeast to perform,” Richards says.

The Convergence platform includes another yeast that hasn’t gotten much attention, as it’s not the primary offering, Ballard says. Bio-Ferm EGA is extremely robust, but is not a yield-enhancing strain. “It’s a very fast strain,” he says. “It’s a strain with very high kinetics.

“There is this very small segment of the industry that is less interested in yield, but is very interested in output, very interested in fast kinetics and very interested in robustness because of their particular circumstance.” For those customers, Bio-Ferm EGA, coupled with Alcolase 146, still provides extraordinary levels of GA expression.
“We encourage customers to increase profitability with CV5, but some are interested in Bio-Ferm EGA,” Ballard says. “We have a couple plants running product and it’s proving to be very interesting as well.”

Trehalase Train 

Cargill also is focusing on trehalase expression, with its biocatalyst, an advanced Saccharomyces cerevisiae, according to Greg Poynter, principal biotechnologist for Cargill. The combination of its three main traits—glycerol reduction, GA and trehalase expression—allows producers to reduce enzyme costs while increasing yield through the reduction of byproducts, Poynter says. 

“The third trait, a secreted trehalase enzyme, is what I feel differentiates our strain from the competitors,” Poynter says. “Through an extensive screening process, we identified several viable trehalase enzyme candidates and then engineered them into the yeast.”

The trehalase hydrolyzes trehalose, he explains. “Our solution results in a significant reduction in the overall DP2 sugars at the end of fermentation and a corresponding increase in ethanol titers.
“Cargill’s yeast would bring another competitive offering into the market with the added benefit of a secreted trehalase enzyme. The trehalase offers the same performance as commercial enzyme cocktails containing the trehalase, but with the advantage of having the yeast supplying the enzyme.”

Cargill’s yeast has demonstrated between 2% to 4% yield increase, depending on the mash and fermentation conditions. Cargill has been using its yeast developed in-house at its North American ethanol plants but is exploring options to release the technology to the broader ethanol industry, Poynter says.

Glycerol Goals

Mickel Jansen, senior scientist in fermentation for DSM Advanced Yeast & Enzymes, says ethanol producers will always want yield enhancement and robustness of yeast. Looking forward, he says new strains will continue to innovate in those areas, but it’s crucial to pay attention to what the altered yeast do to the process. 

“Biology has quite some astonishing powers and possibilities for opportunities,” he says. “That’s what we are exploring here, to the benefit of the customer, of course.”

The first wave of advanced yeast was related to glycerol reduction, the second was related to GA, and last was robustness, he says. Ballard says, looking back, those iterations seem almost rudimentary, considering how far development has come.

“Glycerol is still being produced and, for me, that’s kind of the ultimate (opportunity),” Jansen says. “It’s not zero. Can we get there?”

Glycerol is needed in the process for robustness, he says, but there’s more potential in getting more sugars for yeast to be converted. “I can see already some trends there. I expect that would happen more. I would not be surprised if it goes in that direction more.”

Cargill is on top of it. “Glycerol and trehalose represent the major byproducts in an ethanol fermentation, so those were the top targets for the strain development program,” Poynter says.

But, Jansen points out that, in an anaerobic environment, like fermentation, both yeast biomass and electrons are being produced. “The yeast can only compensate if it also makes glycerol,” he explains. “In that sense, it’s kind of a yield loss. The ones that offer a lower glycerol technology do have a certain metabolic pathway introducing the yeast that can partly circumvent that. … Making less glycerol makes higher yields.”

Poynter addresses that. “One of the challenges with glycerol reduction is that many of the solutions, while effective in reducing glycerol, negatively impact ethanol productivity. The modifications we have made to our strain brings the best of both worlds, reduction in glycerol without impacting productivity.”

Jansen adds that process control is crucial in partnership with an optimal yeast. “You cannot fully control your fermentation temp in the process. If you really want to squeeze out the best potential of every yeast, then also the best process control is needed.”

Process control and yeast control go hand-in-hand, he says. “You really have to also think about process control, not only what the yeast can control.”  

Compelling Economics

Despite the tough couple of years producers have had, the timing is good for a new product, Ballard assures.

“In this case, the economics are so compelling it’s helped in our favor. And it’s a product that works very well without a lot of on-site tweaks.”

Richards agrees. “The robustness has really decreased the support requirement from the technical support service managers and the team has also really adapted to provide remote support, and on-site support where customers allow it.

“But with improved robustness and overall strong performance of this strain coupled with our existing knowledge in rolling out products, it’s been pretty smooth,” Richards says.

“What we’ve all learned during this pandemic is what can be done without being on-site, without being face to face,” Ballard says. “We’ve pivoted to ensure our team is able to provide the high level of technical support that is valued in the industry, but, very often, that has to be done virtually.”

“While we want to communicate on-site, the remote support has been pretty effective in helping these trials succeed,” Richards says. “It’s been good timing as far as the intro to the industry.”

One doesn’t find out the extent to which business can be done virtually, until forced to do it, Ballard says.

‘Exciting World’

LBDS has plenty of plans for future iterations of its platforms, continuing to enhance yield and improve robustness.

“We’ll continue to work on different types of enzyme activity to help producers, in terms of some of their other goals with coproducts,” Richards says. “The next step is to continue to enhance yield where we can and overall improve fermentation rate and fermentation robustness.”

Ballard says, “I think it’s an exciting world, when you look into the future—what we can do with GM yeast. There are other enzymes we can express, and we still believe we can get more yield out of the process. So we have plenty of options to work on.”

Poynter says biotechnology has expanded by leaps and bounds over the past decade. “By leveraging these ever-expanding capabilities, the yeast providers can significantly improve the process economics for ethanol producers by reducing costs and improving profit margins.”

Ballard always expresses appreciation for competition, helping to motivate innovation. “Competition has certainly been very active and there’s a lot of good products out there,” he says. “We’re very happy we’re currently winning the yield race. But the only way we’ll stay ahead is by continuing to innovate, so we’re continuing to do just that.”

Author: Lisa Gibson
Ethanol Producer Magazine
701.738.4920
lgibson@bbiinternational.com