Two microbes in sequence more than triple the lysine in faba beans and rapeseed press cake

The order in which the bacteria run is the core of the design. C. glutamicum makes the lysine, but only after the Bacillus step has cut the plant proteins down and released nitrogen it can use ^[2]. By that account, the new lysine is built from nitrogen the beans and press cake already held. Christian Solem of the DTU National Food Institute said the partial breakdown has a second use. "The interesting thing is that we can use microorganisms to improve the amino acid profile of plant-based ingredients while also making plant proteins easier to digest by partially breaking them down. This is particularly beneficial because many crops contain antinutrients that make it harder for our bodies to absorb the nutrients found in plant-based foods," he said ^[8].

Together, the fold changes and the final concentrations give the starting points. Faba beans began at about 11 g of lysine per kilogram of dry matter and rapeseed cake at about 8 g ^[1][2]. Fermentation therefore added roughly 26 g and 21 g per kilogram ^[3]. The fold figures are rounded to one decimal place, so those baselines are approximate.

The release says the result means more nutritional value from the same quantity of food or feed ^[13]. The measurement behind that statement is a concentration in dry matter after fermentation ^[4]. A per-kilogram figure can't tell you how much of the starting kilogram survived two rounds of microbial growth, and the release reports neither that nor any measurement of digestibility.

In feed, a shortfall of essential amino acids slows growth and can make animals ill. Producers deal with it today by feeding more protein than the animals need, or by adding amino acids produced through fermentation ^[9]. The DTU-Aarhus approach does the fermenting inside the ingredient itself ^[2]. Organic pig and poultry farms are not allowed the added route, according to Jan Værum Nørgaard of Aarhus University ^[10]. He said the surplus protein has a cost: "If the animals are given more protein than they can utilize, they excrete more nitrogen via urine and feces, which places a strain on the environment" ^[11].

In my view the organic feed case is the nearer application. The ban on added amino acids leaves a specific gap, and an ingredient that carries its own lysine is aimed straight at it. That view holds only if the dry-matter and digestibility figures come out well. Both crops are grown in large quantities in Denmark and the rest of Northern Europe, and both can replace imported soy in feed ^[12]. The researchers also say the method works well with other plant crops ^[14] and could help ease malnutrition in low-income countries ^[15]. The figures published so far cover faba beans and rapeseed press cake ^[4].