Wood from waste and by-product streams could replace petroleum as a sustainable alternative for the production of high-value applications such as plastics, additives for animal feed and cosmetics. But this value chain only has a future if it is technically, economically and environmentally sound. Within the BioWood project, these various facets of the chain are being studied and optimised.

The mission behind the VLAIO-funded project is ambitious. It involves the development of a new bio-based value chain in Flanders. This chain is based on woody biomass from all kinds of waste and by-product streams, and aims to produce high-quality agro-industrial chemicals. Within BioWood, VITO is working together with researchers from the KU Leuven (project co-ordinator) and the University of Antwerp. Besides that, there is, among others, a collaboration with the animal feed company Nutrition Sciences.

Within BioWood, everything needed to get the chain off the ground in Flanders is being investigated in detail. From the origin and supply of the biomass to the marketing of potential end products. Because of this broad approach, the project has been divided into several working packages, each dealing with a part of the chain. ‘In one of the packages, an inventory is being made of the available woody biomass streams in Flanders,’ says Frederik De Bruyn, business development manager at VITO. ‘Another working package involves fractionating the wood chips with a biorefinery process. The resulting fractions can be further processed chemically or biochemically – just as in petrochemical oil refining – into all kinds of high-quality applications. The biomolecules obtained are then tested for their safety too, both for the environment and for human health. And finally, of course, the economic picture also has to be correct: the entire chain must be profitable and the applications must be able to be sold at market prices.’

Cheaper with decentralised biomass hub

To connect the different pieces of the chain and to fit the value chain into the Flemish landscape, MooV, the service platform developed by VITO (Sustainable Chemistry Unit) is being used to make supply chains more efficient. ‘MooV calculates different scenarios in which costs are minimised and various waterfall principles are examined,’ says Annelies De Meyer of VITO. ‘We are taking into account the costs of “harvesting” the wood, storing it, processing it into wood chips, transporting it and ultimately refining it to determine the optimum location for the industrial biorefinery. Is it best to do this close to the origin of the woody biomass, or rather close to the companies producing the final applications? ‘This optimum location strongly depends on where the individual steps take place: at the edge of a forest, in a (de)centralised biomass hub, next to the biorefinery, etc. We have discovered that the logistical process can be made 15 percent cheaper if we choose a decentralised biomass hub, where the harvested biomass is stored and processed into wood chips. The size and location of this hub plays an important role and is also being optimised by MooV.’ For the inventory of the available wood biomass, VITO is working with the KU Leuven, which is developing a new forest map for Flanders for this purpose. The techno-economic analysis of the biorefinery process is being carried out by experts at the University of Antwerp.

Oligosaccharides cut to size

The biorefinery of the woody biomass forms the core of the new value chain. This is also the field of activity for the Sustainable Chemistry Unit. ‘Within BioWood, we're going to be working with hemicellulose, which alongside cellulose and lignin is a main constituent of wood,’ says Winnie Dejonghe of VITO. ‘From this, we're aiming to make oligosaccharides, short biopolymers that have a multitude of applications. Dejonghe and her colleagues are doing this by cutting the polysaccharides from the hemicellulose into pieces with enzymes and then separating molecules of a specific length by filtration across membranes. This method works well at low temperatures, is easily controllable and produces no toxic substances – unlike some existing industrial processes. In recent years, VITO experts have been able to significantly increase the efficiency of the process. ‘By late 2021, when BioWood ends (the project lasts for four years), we want to gain even better control over the length of the oligosaccharides ultimately produced, and their effect on applications.’

For example, the length of the sugar chains determines the prebiotic activity of these oligosaccharides. Dejonghe: ‘This is one of the high-quality applications we're investigating. We want to use the molecules to stimulate the growth of beneficial bacteria in the intestines or on the skin, for example. By adding them to animal feed, the use of antibiotics in livestock breeding can be reduced. And there are also some cosmetics manufacturers that want to use bio-based oligosaccharides in skin ointments.’ At present, the effect of their addition to chicken feed is being evaluated by the KU Leuven. In the meantime, the way is already being paved for later marketing, thanks to the presence of Nutrition Sciences (specialising in additives for animal feed) on the advisory board of the BioWood project.

Safety of new molecules

Not only will the logistics and production in the new value chain be examined  – the safety for the environment and human health is already being investigated. De Bruyn: ‘That's actually a very special aspect of this project. At an early stage of the research and development of potential applications, the components are already being toxicologically tested.’

This is also being done at VITO, where the Sustainable Health Unit has a wide range of safety tests for humans and the environment at its disposal. ‘The applications can only be marketed if they meet the strict European REACH legislation,’ says Hilda Witters of VITO, who is mainly studying the ecotoxicity of refined lignin within BioWood. ‘We screen for damage to three freshwater organisms: algae, water fleas and fish. We do this with raw lignin fractions from poplar and pine, for example, as well as with monomers purified by the KU Leuven.’

By researching various toxicological properties such as acute toxicity and hormone disruption so early in the development of the new chain, VITO is honouring the safe by design principle. ‘This way, we can quickly provide feedback to the researchers working elsewhere in the chain. Based on our feedback, they can then adjust their choices in the development of bio-based molecules as necessary.’ In concrete terms, this will soon be done by testing the environmental safety of, for example, lignin fractions and monomers that have proven to have a good antibacterial effect in the chicken tests carried out by the KU Leuven. ‘Based on the results, a selection can then be made for further optimisation in process chemistry or for potential valorisation,’ says Witters.

The BioWood project reflects the strong collaboration and complementarity between the two VITO units. ‘Thanks to the broad expertise we have in-house, we can deal with logistics, production and toxicology in the new value chain. That makes BioWood a very nice cross-unit story,’ says De Bruyn.

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