Building a ‘Biological Engine’

A self-evident truth for any ethanol producer, the science of fermentation makes ethanol production possible. However, today’s advanced yeast enable production to run at a scale hard to imagine 20 years ago. Today, genetically modified yeasts that coproduce glucoamylase and withstand hostile environments are commonplace, thanks to the innovation and research of yeast and enzyme producers.

Pioneering: Lallemand
Back in the day, ethanol producers used yeast that was not far removed from baker’s yeast to ferment hundreds of millions of bushels of corn into ethanol. Craig Pilgrim and Matt Richards remember those days. Numerous breakthroughs in yeast science benefited producers throughout the 2000s. Then, in 2012, the ethanol process was forever changed with the introduction of glucoamylase-expressing yeast, which opened the door to genetic enhancements that help producers maximize production.

Enzyme-expressing yeast helped pave the way for producers to broaden their view of what enhancing their process could mean, according to Richards. “There’s a lot of new technology that’s been introduced from the process side and equipment side in terms of oil separation, fiber separation and higher protein products, but [we are] able to also advance the biological engine within the facility and enhancements that can happen there,” he says.

The company acquired BASF’s enzyme business and leveraged that gained expertise in product development, looking at ways to improve glucoamylase replacement, study additional enzyme activity and explore further proteins.

Manufacturing ‘Cell Factories:’ IFF
Long before IFF launched its first line of genetically modified yeasts, it was working extensively with so-called “cell factories” to produce advanced enzymes, explains Hans Foerster, marketing director for the company’s grain processing business. Those branches converged in 2011, when IFF started to develop enzyme-expressing yeasts that could deliver glucoamylase.

The impact of these yeasts is evidenced in the volume increase that has occurred from 2015 to 2024. Foerster highlights that USDA records show that the ethanol industry’s yield has increased by 10% while corn usage for ethanol has only increased by 5%.

Pushing Boundaries: Novonesis
Novonesis’ first enzyme-expressing yeast entered the market in 2018. Titled Innova Drive, this glucoamylase-expressing yeast was the first of 10 modified yeasts that Novonesis has brought to the market since, according to comments provided by Billy Whitlock, global marketing manager with Novonesis, and Andrew Dilworth, North America regional marketing manager with Novonesis.

“[Ethanol producers’] business objectives demanded more yield and more ethanol across a wide range of operating conditions and challenges, and that was a key priority in our innovation goals—to bring a biosolution to the market that would enable consistency and power through tough fermentation conditions,” Whitlock and Dilworth tell Ethanol Producer Magazine.

Novonesis utilizes information on ethanol producers’ fermentation challenges, such as failed fermentations due to heat or bacterial infections, to drive new product development.

‘Yield Is King:’ CTE Global
Enzyme and yeast provider CTE Global started off in the enzyme-expressing yeast space in 2018 with the Innova yeast line, which brought increased robustness and glucoamylase expression. According to Pedro Peña, vice president of technology and innovation with CTE Global, the product proved itself in yield benefits compared to others.

Three fundamental principles guide the company’s innovation in enzyme-expressing yeasts. “First, the feedstock should be converted to fermentable sugars as close to completion as possible,” Peña says. “This informs our approach of enzyme expression for the yeast to work in synchrony with external glucoamylase blends and associated enzyme activities.” CTE’s second principle is to ensure that sugars are metabolized efficiently, funneling as much of the carbon flux as possible toward ethanol. Finally, the yeast should do that day in and day out, consistently throughout the year, even under the inevitable adverse conditions that pop up in the process.

Leveraging Science: Leaf by Lesaffre
For Leaf by Lesaffre, the ethanol industry’s excitement about glucoamylase-expressing yeasts inspired a pivot away from yeasts and enzymes for cellulosic ethanol production toward applying genetic modification to first-generation ethanol production. The company’s first GA-expressing yeast came onto the scene in 2017, according to Kelly Hahler, global technical application manager with Leaf.

When ethanol producers started buying genetically modified yeasts, they had questions, she recalls. The new yeasts came in a cream form rather than in a dry form. At the time, yeasts would be rehydrated and propagated before adding them to the fermenters. Ethanol producers wanted to know how to propagate yeasts that came in a cream and how to handle the different logistics surrounding yeast deliveries.

Initially, ethanol producers saw genetic modification primarily as a means to reduce costs associated with exogenous enzymes. Over time, their focus shifted to yield maximization by reducing the amount of glycerol coproduced with the ethanol.

Leaf has not abandoned its roots in C5 sugar conversion innovation, Hahler says. C5 sugar conversion constitutes the next major opportunity for a new production boost, but the surrounding process changes and capital investment required to effectively process lignocellulosic feedstocks at a full scale is not something the industry is prioritizing—yet.

“Right now, in the industry, there’s such a drive to reduce carbon footprint, and so, there’s a lot of innovation that’s still supporting that,” Hahler says.

Continued Evolution: Phibro
With a long history serving the ethanol industry with technical expertise, Phibro also added enzyme-expressing yeast to its portfolio nearly half a deade ago to meet the evolving needs of its ethanol customers. Jenny Forbes, vice president of sales and service with Phibro, explains that Phibro Ethanol began offering Kinetx, a line of glucoamylase-expressing yeasts, in 2021. Developed in collaboration with Ingenza Ltd., a UK-based engineering biology firm, Phibro’s Kinetx strain was created through Ingenza’s proprietary strain construction and adaptive laboratory evolution (ALE) platforms, explains Moira Adams, product manager of yeast and enzymes with Phibro. READ MORE