6th International Conference on Novel Enzymes, held in Darmstadt, Germany

Dr. Sarah Prexler visited the Novel Enzymes Conference which is held every other year, a conference series devoted entirely to the optimization of existing and the development of novel biocatalysts through protein bioengineering, as key enabling tools for the bioeconomy. On her poster, Sarah presented part of her doctoral thesis, namely her mutational approach to understand structure-function relationships of plant polyphenol oxidases (PPOs). Plant PPOs can oxidize diphenols to quinones which then polymerize and form e.g. the brown colour in cut fruits such as apples, but some few can also convert monophenols into diphenols - a reaction that is of potential interest to industry. Several hypotheses have been proposed to explain this ability, but they have not yet been rigorously experimentally tested. Our group was the first to establish heterologous expression of plant PPO genes in E. coli yielding catalytically active enzymes.This enabled Sarah - together with Martin Frassek who did his Master thesis with her - to disprove the current hypotheses and to shed new light upon this long-debated question, paving the way for future studies on improving PPO’s monophenolase activity. Sarah was impressed by the excellent quality of the work presented during this conference, and also by the strong interest of industry in enzyme engineering that was apparent. Certainly, the contacts she made will be helpful for the next steps of her scientific career.