Inside Grass Biorefinery: A Conversation with the Founder and Advisor of Grassa
Johan Sanders explains how local protein production improves dairy sustainability.
In this interview, Johan Sanders (Founder/Advisor of Grassa) shares his vision for transforming livestock systems through grass biorefinery, nitrogen efficiency, and circular nutrient management. In conversation with Alejandro Vergara (CEO of ODOS), he explains why the future of dairy farming is not about producing less, but producing smarter.
What Is a Grass Biorefinery?
At its core, the grass biorefinery is surprisingly simple. Freshly harvested grass from a small local radius is mechanically pressed in a screw press. Johan explains, “What we do is pressing grass.” This pressing process separates the biomass into two distinct streams: a fibrous solid fraction known as press cake, and a green juice fraction.
The press cake contains what Johan calls resistant protein. Unlike conventional grass or silage, where much of the protein is broken down inefficiently in the rumen, this resistant protein bypasses the first stomach and is absorbed later as amino acids. “That protein is not broken down in the rumen,” he explains. “It happens later in the stomach, and then it’s taken up as amino acids.” As a result, cows use the protein more efficiently, requiring less crude protein overall and producing less nitrogen in manure.
The juice fraction contains soluble protein, which is extracted, coagulated, and dried. According to Johan, its amino acid profile is at least as good as soy protein, and in some aspects even better. This makes it a viable alternative to imported soybean meal for pigs and poultry.
Can Grass Replace Soy?
One of the central questions in the interview concerns performance. Does grass protein really match soybean meal in practice?
Johan refers to trials conducted in Ireland and at Dairy Campus in the Netherlands. In these studies, cows were fed 138 kilograms of crude protein per ton of feed instead of the standard 160 kilograms. The result was clear: “We get the same amount of milk.” In other words, less total protein input led to the same milk production.
This is significant because soybean meal is typically used to increase protein levels in feed. If cows can maintain output with lower crude protein levels, it means protein is being used more efficiently and less soy is required in the ration. In regions like the Netherlands, where ammonia emissions are under strict legal scrutiny, improving protein efficiency has direct environmental and regulatory implications.
Why Is Nitrogen the Real Challenge?
Johan frames the entire discussion within the planetary boundary for nitrogen. Globally, the safe limit is around 90 million tonnes of fertilizer nitrogen per year. When divided by the global population, this translates to roughly 12 kilograms of nitrogen per person annually. In Europe, nitrogen use far exceeds this level.
In the Netherlands, nitrogen inputs come from two main sources: fertilizer and imported feed protein. Johan points out that when cows consume grass under normal conditions, they digest only about 75 percent of the grass cells. The remaining 25 percent passes through the animal and contributes to nitrogen losses. “That 25 percent contains a lot of valuable protein,” he notes.
By separating this fraction through biorefinery and reallocating it, nitrogen emissions can be reduced significantly, potentially by around 30 percent. At the same time, less protein needs to be imported from South America or the United States, which also reduces the flow of nitrogen and phosphorus into the system.
How Do You Convince Farmers to Adopt This System?
Rather than proposing herd reductions, Johan focuses on practical incentives.
Grassa has initiated a pilot project with 40 dairy farmers in the Netherlands, particularly in areas close to Natura 2000 zones where nitrogen restrictions are strict. Farmers using the press cake report similar milk yields with lower crude protein input and lower emissions. For many farmers, this can help maintain their operational permits. “That gives them a license to produce,” Johan explains.
The approach is not about imposing limitations, but about offering a system that improves efficiency while keeping productivity stable.
Who Pays for Mitigation?
When Alejandro raises the issue of cost, especially around slurry acidification and methane reduction, Johan responds with system thinking.
“If we make biogas from that same manure, we see that the production of biogas is almost doubled,” he explains. By integrating biological acidification, anaerobic digestion, and ammonia stripping, the system reduces methane emissions, increases biogas output, and produces renewable fertilizer that can replace synthetic inputs.
The key insight is that mitigation should not be viewed as an isolated cost. When designed holistically, environmental improvements generate economic value.
Does Grass Have a Role Beyond Animal Feed?
The conversation also moves toward the future of plant protein. Johan explains that Grassa is working to optimize the soluble protein fraction for human consumption. As consumer demand shifts toward plant-based protein, grass and legumes could become part of a broader protein transition.
“It’s not only important for the environment,” he says, “it is also important for profit.” Consumers are increasingly willing to pay for sustainable plant protein.
