Most companies in the food industry use stainless steel to avoid bacterial growth. But for Chr. Hansen, the art is to create good growing conditions for certain bacteria in large tanks made of stainless steel.
“Over the past ten years, we’ve seen a significant increase in demand. This means that we constantly expand our factories. At the same time, new applications have been developed, so we need to produce entirely different types of bacteria,” says Susanne Grøn, Vice President of Innovation Management in the company. She has an MSc in engineering from DTU, specializing in bioprocess technology.
“As process engineers, we’re responsible for the last part of the research and development work before full-scale production. Process engineers often have to make decisions which may have extensive financial consequences.”
In the pharmaceutical industry and other forms of biotech, it is quite common to grow bacteria. Here, the microorganisms are generally small factories which are to produce proteins or the like. For Chr. Hansen, however, the bacteria are the product.
“Seen from the outside, our processes may not seem very complex compared with many other industries. But the complex part has to do with living organisms. The bacteria must at no time during the process be exposed to conditions which they cannot tolerate. In addition, they must be alive after we’ve sold them. Sometimes, they must even be able to withstand being stored at room temperature for two years,” explains Susanne Grøn.
New bacterial strains pose a challenge
Over the past 11 years, Chr. Hansen has seen a stable and significant annual growth of approx. eight per cent. The company is headquartered in the Scion DTU science and technology park , while the production takes place at different locations in Denmark as well as in Germany, France, and the USA.
"We bring our sleeping bags and are happy to wake up several times during the night to take samples from the tanks."
Susanne Grøn, Vice President of Innovation Management, Chr. Hansen
At the same time, Chr. Hansen has entered entirely new markets. One example is bacteria that protect plants as an alternative to pesticides. Certain bacteria have also proven beneficial to human and animal digestion by improving the intestinal flora. Finally, there is a strong interest in bacterial cultures which can prolong food shelf life and thereby prevent food waste.
“The broader objective is a major process technological challenge. The backbone of our business are lactic acid bacteria, and the bacterial species required for plant protection, health promotion, or shelf life improvement are entirely different. Each type of bacteria has unique special demands. But our fundamental technology platform has actually proven solid—also for species other than lactic acid bacteria,” explains Susanne Grøn.
Chr. Hansen has hundreds of different bacterial strains in production, and approx. 25 new strains are introduced every year.
When a new strain is put into production, the first step is to carry out a thorough characterization. It is particularly important to know the bacteria’s metabolism, i.e. how they convert nutrition, which Chr. Hansen’s researchers are responsible for studying.
Subsequently, pilot-scale and then large-scale production can be commenced.
Sleeping bags in the production hall
The company’s process engineers often travel to Germany, France and the USA.
“Because we’re talking about living organisms, we must never take it for granted that a process that works in the laboratory also works in large tanks. So every time it does, it produces a sense of happiness for which we’re willing to make every effort,” says Susanne Grøn. “We bring our sleeping bags and are happy to wake up several times during the night to take samples from the tanks.”
Process engineers often face dilemmas in connection with the upscaling. To illustrate, Susanne Grøn provides an example from the production of probiotic bacteria—i.e. health-promoting bacteria:
“Probiotics are usually produced as freeze-dried bacteria, which must remain stable at room temperature for at least two years to prolong product shelf life. It’s very demanding to produce a stable bacterium. All unit operations in the production process contribute to the stability of the final product. Sometimes, the process engineer must choose fermentation conditions generating a lower yield, but more stable bacterial cells in the long term.”
In other words, it may be of great economic importance to make the right process choice.
“You need a holistic approach. It takes some years to learn.
Neither experience nor gut feeling is enough in itself,” Susanne Grøn underlines, adding:
“To be a good engineer in our industry, you need good statistical skills. Your decision must be based on weighted risk. This means that you must be able to handle variables for, maybe, 20 different fermentors. Statistics have proven to be an extremely efficient tool. Fortunately, DTU graduates are very talented in that area.”
Done playing second fiddle
In addition to statistics, online technology is a strong tool:
“There’s a lot going on in relation to measuring methods that help us take an outside look at what’s happening inside the bacteria. This way, we get a pretty good picture of the ‘fitness’ of the cells.”
During the 20 years Susanne Grøn has been employed at Chr. Hansen, she has experienced an increasing respect for process engineers:
“Previously, we probably used to play second fiddle compared to our research and development colleagues. But in recent years, we’ve attracted a lot of attention. At the same time, the company has been given a higher profile. Especially during the last three years, talented young engineers from all over the world have applied for a job with us.”
According to Susanne Grøn, this interest is not only triggered by the fact that things are going well financially for Chr. Hansen:
“There’s generally a major focus on the positive applications of bacteria. Many companies in several different industries see business opportunities, but they don’t have more than 100 years’ experience in upscaling bacterial growth significantly. Then they come knocking on our door.”