Paper accepted: “Synergistic antimicrobial effect of chitosan polymers and oligomers”

Today, the first paper of Dr. Maha Attjioui’s doctoral project was accepted for publication in the journal “Molecular Plant-Microbe Interactions”, one of the highest ranking of the phytopathology journals. What we report here was a typical example of serendipity, but also of a successful collaboration between Academia and Industry. This is why Dr. Dominique Gillet, our chitosan provider for twenty years, is a co-author on this paper. We had had a joint research project in which we had been analysing structure-function relationships of chitosans for the optimisation of their use as a sustainable plant disease protectant. Based on the results of this project, Dominique had optimised his production processes, allowing him to produce a highly efficient, high molecular weight, plant disease resistance-inducing chitosan. But because of its high Mw, its solubility was too low to develop a successful product based on it. Dominique developed a way to reduce the Mw so that he was able to prepare a highly concentrated solution ready to be sold as an ingredient for plant protectants. But we were surprised that in spite of the lower Mw, the product still retained its efficiency, its performance was even improved compared to the initial product. It was Maha who finally understood that this is because of a synergistic effect of chitosan polymers and oligomers present in the new formula. Apparently, it is not good enough to simply look at the average Mw of a chitosan solution, but we need to consider also its Mw dispersity. In hindsight, it seems almost trivial, as often. But the Mw dispersity is a factor that has so far been ignored in the scientific literature when assessing biological activities of chitosans. And trust me: this is true not only for chitosans!