Protecting crops with sugar chains

Pesticides are a constant source of concern. Due to health risks, several substances used to protect crops against fungi and insects have since been banned, including mancozeb (linked to cancer and birth defects) and chlorpyrifos (linked to changes in brain structure in children). There are also unwanted environmental effects. Pesticides seep into surface and groundwater, where they affect ecosystems (in ways that are still not fully understood). Furthermore, beneficial insects such as bees can also fall victim to the use of such substances.

There are friendlier alternatives for crop protection, but their production is complex and difficult to scale up. Moreover, they are nowhere near as effective as synthetic pesticides. The UGent spin-off B-COS, founded just this past June, is now introducing a method to produce molecules from genetically modified bacteria that vaccinate plants against diseases and pests. CEO and co-founder Chiara Guidi: ‘With our COS products, we have already achieved impressive results this past summer in field trials at certified research organisations.’

Triggering defences

COS stands for chitooligosaccharide. These sugar chains are found in the shells of crustaceans, but also in the cell membranes and walls of insects and fungi. ‘They consist of monomers of N-acetylglucosamine and glucosamine,’ explains Wouter Demeester, CTO and co-founder of B-COS. ‘We produce COS molecules using Escherichia coli bacteria in bioreactors. We have modified these in such a way that they link a specific quantity or combination of monomers together. This allows us to obtain various types of COS products.’

‘With chemical or enzymatic production, you are limited in terms of scalability’

Wouter Demeester

The resulting powder is then applied to the crops. ‘There, they trigger the plant’s immune system, and the plant develops a “memory” of those COS molecules,’ explains Guidi. ‘So that when an actual pathogen or pest comes along, the plant’s defences are activated. Exactly like a vaccine in humans.’

Economically attractive

Although the concept of COS as a plant vaccine is not new, B-COS’s bottom-up method is. ‘Until now, these molecules were produced primarily through chemical or enzymatic processes,’ says Demeester. ‘But that limits your scalability and makes it considerably harder to control the composition of the final product. We know that our concept is genuinely economically attractive for farmers.’ B-COS’s technology stems from 15 years of research by the Ghent synthetic biology group led by Marjan De Mey. Guidi and Demeester became involved in the project towards the end of the previous decade. It quickly became clear that a start-up could emerge from it — one that was, incidentally, founded together with business developer Maaike Perneel, now CCO.

‘But that turned out to be no easy feat, as this is both a biotech and an agritech company,’ says Guidi. ‘As if scaling up at the lowest possible cost weren’t already challenging enough, you also have to contend with a limited number of crop cycles per year. You cannot test and validate all year round. On top of that, the registration process for a new agricultural product is extremely complicated.’

Rotation

Guidi and Demeester are currently in talks with investors and have just been admitted to the Biotope Incubator in Ghent — a significant milestone. ‘Within a few years, we hope to have our first product actually on the market,’ says Guidi. ‘This will be a COS that stimulates plant growth during periods of drought and stress. We are targeting the Benelux, but also Southern Europe, where the effects of climate change on agriculture are already clearly visible.’

‘Once a pathogen or pest comes along, the plant’s defences are activated’

Chiara Guidi

But first, more field trials with the COS products must be conducted, says Guidi. ‘Up to now, the tests have covered a maximum of one hundred square metres of treated area. The next step is to expand that to several hectares.’ Production must also be scaled up. The first step towards approximately 150 litres per bioreactor vessel has been taken as a pilot, but ultimately the target is 75,000 litres. Demeester: ‘We are also looking at improving the formulation and want to determine precisely how much powder needs to be applied to the land for an optimal effect.’

B-COS’s mission is to protect crops in a natural way. That does not mean, however, that synthetic pesticides can be replaced entirely by COS, according to Guidi. ‘Because those simply work very well too. We see our product more as something that can be incorporated into rotation alongside conventional pesticides and other biopesticides. So that, overall, less of the toxic substances are needed. And so that you are working both preventively and when the disease or pest has already taken hold. In that way, we hope to become part of the future of agriculture.’