Paper accepted: “A chitin deacetylase as biocatalyst for the selective N-acylation of chitosan oligo- and polymers.”

Today, Max Linhorst’s paper on the biotechnological derivatisation of chitosans using a recombinant chitin deacetylase acting in reverse was accepted for publication in the renowned journal “ACS Catalysis” of the American Chemical Society. This is the cornerstone of Max’ doctoral thesis which he is about to submit. His project was supported by the NRW Graduate School “grEEn” on the development of sustainable batteries in which chitosans played a prominent role. Max produced a lot of different chitosans for his fellow doctoral candidates to be used for different purposes in batteries, in attempts to make them more sustainable. When Jasper Wattjes, then also doctoral candidate in our group, found that chitin deacetylases can be used in reverse, in the presence of excess acetate, to N-acetylate polyglucosamines instead of de-acetylating chitins, Max tried the same using different carboxylic acids instead of acetate, and obtained the respective acylated chitosans. So far, the production of chitosan derivatives with improved material properties had only been possible using chemical methods. Max’ paper is the first one to describe a biotechnological process, which can be adapted for a huge variety of functional chitosan derivatives, due to the implementation of “clickable” carboxylic acids in this process. This is not only potentially more environmentally benign; the products of the biotechnological process are also highly likely to differ from their chemically produced counterparts. Chemical processes yield random patterns of substitution, while the enzymatic process may yield non-random, e.g. blockwise distributions of the substituted residues. In the case of acetyl groups, Jasper and his colleagues had shown that these non-random acetylation patterns strongly influence the physico-chemical properties and the biological activities of the chitosans produced. Max now provided evidence that enzymatic acylation leads to non-random acylation patterns, too. And he succeeded in scaling-up the production process. This potentially gives access to a completely new generation of chitosan derivatives, with hitherto unknown properties. A bonanza…