A new research springboard

The main interest of this research is to validate the methods (including nuclear magnetic resonance, mass spectrometry, chromatography, etc.) which make it possible to model the structure of lignin. “We now have a database making it possible to instantly and precisely visualize the different types of lignin and their chemical structure. This information can constitute a precious springboard for other work making it possible to potentially assign a value to every type of waste”.

A note of caution! By “value”, we mean a very broad concept, including economic, environmental and also sociological considerations. Explanation: “Systematically trying to replace products of a petrochemical origin by bio-sourced materials is a little naive or can be described as ‘greenwashing’. What is important now, is to conduct complete life-cycle analyses of the new products from the moment of planting to the final elimination phase. On this basis, and from a toxicology point of view (we know practically nothing about the toxicity of by-products of lignin), we can say that research is only in the primary phase”, states Aurore Richel.

The other limitation of the “green chemistry” concerns the economic scope of bio-sourced materials, particularly in Belgium. It is certain that, theoretically, the field of this “circular economy” (each waste product from sector X is a raw material for sector Y) is enormous. Lignin is also perceived as a credible alternative to petrol for the manufacture of chemical products as basic as benzene, toluene, xylene, etc. Some laboratories are already trying to depolymerize it, which is to say to deconstruct it down to its basic structures as much as possible, so that the chemical industry can use them. It is still important to be aware of the benefits and limitations of the geographical zone where this research took place. “At Gembloux Agro-Bio Tech, we are convinced that it is necessary to concentrate on niche markets in our own regions that are supplied by local raw materials. Neither Wallonia nor Belgium itself will be able to supply large quantities of raw materials for these new products and molecules. This is quite simply because our territory is too small. In addition, certain residues already have uses that are unlikely to change: for example, the incorporation of straw into the soil for purposes of soil conditioning, the use of paper “liquors” for the production of energy in situ, etc.”

Put briefly, the equation is both fascinating and complex. On one hand, the European political context, at a national and local level which, by setting directives and decrees (and in our country the GreenWin competition pole), promotes the diversification of energy supply and the search for more “sustainable” solutions, and on the other hand, forestry or agricultural production of quite modest quantities, which must be made to be as constant ad homogenous as possible in order to meet market needs. These do not tolerate irregularities linked to the seasons or the weather: waste from cutting the lawn is not exactly the same thing as brush or the stones and cooking juice used in the jam-making industry! These needs are themselves potentially subject to various hazards of fashion effects. Because research is necessarily slow, it is subject to contradictory forces. “Our strength at Gembloux”, says Aurore Richel with some enthusiasm, “is to use teams that are more and more interdisciplinary, including chemists, bio-engineers and also economists and market or life-cycle specialists etc. Each of these must be able to count on the know-how of their respective departments: technical, scientific, agronomic, economic statistical etc.”