Paper accepted: The first evidence of cryo-milling improving enzymatic production of chitooligosaccharides from chitin biomass.

Today, a paper by Prof. Jogi Madhuprakash from the University of Hyderabad, to which Dr. Stefan Cord-Landwehr from our group contributed his analytical expertise, has been accepted for publication in the renowned journal “Carbohydrate Polymers”. In this paper, Madhu introduces cryo-milling, i.e. ball-milling at very low temperatures, as an efficient pre-treatment of crystalline chitin to increase its degradability by chitinases and increase the yield of enzymatically produced chitin oligomers. The crystallinity and insolubility of chitin – especially of tightly packed α-chitin which is by far the most prominent form of chitin encountered in nature and commercially exploited for chitin oligomer (and chitosan) production – is probably the number one problem in chitin usage. Chitin oligomers as well as the chitin monomer N-acetylglucosamine have several potential applications, mainly as a functional food and feed additive, but their efficient production from chitin polymers is demanding as chemical depolymerisation easily leads to partial deacetylation, and enzymatic depolymerisation is limited by the insolubility of the substrate, necessitating chemical or mechanical pre-treatments to reduce crystallinity. These processes again have their own problems which can at least partially be overcome by cryo-milling – as Madhu and his co-authors convincingly show in this publication. Madhu had been a doctoral researcher in Prof. Appa Rao Podile’s group during the first Indo-German International Research Training Group on Molecular and Cellular Glyco-Sciences MCGS and as such, he also spent time in our group in Münster where he got to know and appreciate Stefan and his broad analytical expertise. Stefan’s analysis of the degree of acetylation of the chitin before and after cryo-milling, as well as before and after enzymatic hydrolysis, significantly contributed towards convincing the reviewers that our manuscript is worth publishing.