Max Linhorst successfully defended his doctoral thesis: “Next generation chitosan biopolymers through selective chemical and enzymatic modification and functionalization”

Today, Max Linhorst successfully defended his doctoral thesis on the biotechnological production of novel chitosan derivatives using chitin deacetylases acting in reverse. He was supported by his supervisor Prof. Bruno Moerschbacher, by physico-chemist Prof. Francisco Goycoolea from the University of Leeds in the UK, and by polymer chemist Prof. Guillaume Delaittre from the University of Wuppertal. Max had performed his research in the framework of the NRW Graduate School grEEn on Sustainable Batteries. On the one hand, he produced and characterised chitosan polymers with different degrees of polymerisation and acetylation for systematic investigations into their potential use e.g. as electrode binders in batteries. The electrochemical analyses which were performed by partners in the consortium showed that in some cases, chitosans equalled or even outperformed the currently used chemicals – though the way to an actual use is still long. In some cases, the chitosans had to be functionalised, e.g. by crosslinking them via citric acid, to improve their performance. While these functionalisations were performed in the conventional chemical way, Max explored the possibilities to use biotechnological ways using enzymes. He made use of our recent observation that chitin deacetylases can be used in reverse to N-acetylate chitosans, and his ‘crazy’ idea was to try the same enzymes for N-acylation, i.e. for the attachment of other sidechains than acetate. And to our surprise, this worked! Max performed a very thorough analysis of these unexpected reactions, and this part of his work was then published very well. But he had also other seemingly crazy ideas which also worked better than one would have thought, but these are not yet published. So look for what is to come. Congratulations Max – very well done!