Sugar beet pulp fibers show potential for nutritional supplements and sustainable plastic alternatives

New technology can separate the fibers in the sugar beet pulp left over after sugar production. Part of the fiber can be used as a nutritional supplement due to its anti-inflammatory properties and beneficial effects on our gut flora. Another part of the fiber, the cellulose, can be made into components to replace, for example, plastic.

Using residual products from the production of sugar from sugar beets will help fulfill one of Professor Anne S. Meyer’s visions—to transform our current food production to use raw materials for not just one, but several valuable products.

“We already know this from the production of cereals, for example, which we primarily grow to convert the kernels into flour. But we also utilize the rest of the plant, the straw, the husks, etc. for different purposes, so the whole plant is part of the cycle,” says Meyer.

A similar circular bioeconomic idea underlies the project to utilize the biomass that remains after sugar production.

“I call it my star project because our ambitions are high, but also because the perspectives are so great. Once we have demonstrated the possibilities of utilizing sugar beet for several valuable products, the vision is to expand our thinking to many other similar products on a global scale. These could be raw materials for food products that, due to climate change, will be the food of the future in, for example, Africa or Asia, where production conditions are changing dramatically in recent years and where it is obvious to consider using the entire crop for more than just food,” explains Meyer.

“By using a biologically inspired and enzyme-based technique to separate the fibers in food production residues, we take an important step towards ensuring profitable global utilization of raw materials to make multiple beneficial products. Products that are based on using specific fiber structures in the plant material,” she adds.

The first results

Not many weeks ago, Meyer’s research group succeeded in discovering new enzymes that act on the fibers in the residues from sugar beet production, the so-called sugar beet pulp. The burden of proof now lies in showing how quickly the enzymes penetrate the pulp, where they separate the cell wall components so that the different fibers can be gently separated from each other.

One group of interesting fibers in the sugar beet pulp are bioactive pectin elements, which in previous research projects have been shown to have a beneficial effect on the environment in our intestines. This effect must now be documented, and Professor Susanne Brix Pedersen, DTU, is at the forefront of this work. She researches immunology and the influence of microorganisms in the gut, and with her expertise and her team, she can map the anti-inflammatory effect of fiber and how it affects our immune system.

“As life expectancy increases, so does the interest in staying healthy for longer, and in this context, these health-promoting dietary fibers will be interesting. The goal of our work over the next few years is to both document their effect and define how it is most appropriate to consume these fibers—whether it should be in the form of a capsule to be swallowed, or whether the fibers should instead be added to a food, such as yogurt or a drink, or perhaps used for special nutrition,” says Meyer.

Replacement for plastic

The second group of fibers that can be utilized from the sugar beet pulp is cellulose. Although the cellulose structure is the same, the molecular environment of cellulose in the sugar beet and thus the sugar beet pulp is different from the cellulose we know from, for example, trees. In trees, the fibers are reinforced with lignin, among other things, to keep the plant upright and waterproof for years, whereas sugar beet is a tuber that grows extremely quickly in the soil and is harvested annually.

“Sugar beet cellulose fibers are therefore more malleable, so to speak, and not as stiff as cellulose from wood. We want to utilize this nanocellulose in materials that can be designed for many different purposes—typically to replace different types of plastic. The fibers will be used in composite materials, so-called composites, which can be hard, soft or flexible. At the same time, it is an important ambition that the material can be disassembled and reused again,” says Meyer.

This vision will be realized through collaboration with, among others, the EMPA research institution in Switzerland, which has extensive expertise in innovative applications and recycling of cellulose.

As a process and product is not necessarily sustainable just because it is based on natural materials, the project includes close collaboration with Professor Michael Z. Hauschild, Centre for Quantitative Research at EMPA. Hauschild, Centre for Quantitative Sustainability Assessment at DTU. He continuously assesses whether the project’s initiatives are sustainable. Researchers with detailed knowledge of plant cell wall structure from the Department of Plant and Environmental Sciences, Professor Peter Ulvskov from the University of Copenhagen, are also involved in the work.

The researchers’ initial results show that it is possible to form different types of material from the sugar beet cellulose and that the materials have desirable properties. Intensive work is now underway to show that these materials can be gently disassembled and recycled several times.

In addition, new enzymes and techniques have been developed that are expected to have a lasting impact on the gentle processing of plant materials into new products.