We strongly believe that research should help at contributing to solve problems. And the more urgent and general the questions addressed are, the more satisfying it is to contribute to their solutions. This is why most of our projects are driven by problems - real problems such as the detrimental effects today’s intensive agriculture has on our health and that of our environment, leading to a dramatic decline in biodiversity and to global climate change. We regularly publish the results of our research in scientific journals to make them available to the public. If you are interested, you can subscribe to the regular NEWS which we publish on our website.
In most of our projects, we are collaborating with industrial partners for rapid transfer of our research results into services and products that are economically successful on the markets. This is not always as smooth as we would wish and, therefore, some of our alumni have recently started their own start-up biotech companies, namely Evorion Biotechnologies and Bex-Biotech. We have also set up a service unit within the university, ChitoProf, to offer state of the art chitosan analysis to researchers in Academia and Industry.
ChitoProf
ChitoProf is the service unit of our group, founded to support the transfer of our fundamental research results on structure-function relationships of chitosans into chitosan-based products and services that are successful on the markets. It is now well established that the physico-chemical properties and biological functionalities of partially acetylated chitosan oligomers and polymers strongly depend on their structural features such as the degree of polymerisation (DP) and its dispersity (Ð), the fraction of acetylation (FA), and the pattern of acetylation (PA). Chitosans with well-defined DP and FA are referred to as ‘second-generation chitosans’. Any high-quality chitosan offered commercially and any high-quality chitosan-related scientific publication should at least indicate the chitosan’s DP and FA. As the analytical tools to determine these parameters are rather sophisticated and require experience as well as expensive infrastructure which are not always easily accessible, ChitoProf is offering state-of-the-art structural analyses as a service.
For researchers in Academia, we are offering these structural analyses for a nominal fee covering our own costs only. Costs may be waived if a joint research plan is signed, and results are discussed and published jointly. For commercial research purposes, the service is available under conventional market conditions. Favourable conditions can be granted upon signature of a research proposal aiming at the joint development of a chitosan-based or chitosan-containing product. For further details and prices, please contact us.
Researchers interested in functional analyses of chitosans (or similar compounds) may contact the start-up company Bex-Biotech.
We can also make available well-defined chitosans and chitin and chitosan modifying enzymes in small quantities for research purposes, under similar conditions as described above, and upon signature of a Material Transfer Agreement. However, these materials will have to be prepared on demand and are not available on stock. For further details, prices, and availability, please contact us. Larger quantities – from pilot to industry scale – may be made available in collaboration with our industrial partners.
Structural Analyses
We offer to analyse chitosan oligomers and polymers using state of the art techniques. For chitosan polymers, the standard analysis comprises determination of the degree of polymerization (DP, MW) using HP-SEC-RID-MALLS which also gives the dispersity (Ð) (according to ASTM International method F2602-13), and determination of the fraction of acetylation (FA) using 1H-NMR (according to ASTM International method F2260-03) or using enzymatic/mass spectrometric fingerprinting. We can also determine the pattern of acetylation (PA) using 13C-NMR or using enzymatic/mass spectrometric fingerprinting. Analysis of the DP and FA of chitin/chitosan oligomers is done by UHPLC-ELSD-ESI-MS. In case of pure oligomers or not too complex mixtures of not too large oligomers, we can also analyse the PA using UHPLC-ELSD-ESI-MSn.
Other analyses such as for viscosity or purity (e.g. chitosan content, ash content, water content, heavy metals, proteins) may be performed in collaboration with partners.
Chitosans
We can supply small quantities (1-100 mg) of chitosan polymers with narrowly defined degree of polymerization (DP, ca. 100 to 2500, Ð typically <2) and narrowly defined fraction of acetylation (FA, ca. 0 to 0.7). These chitosans are produced by partial chemical re-N-acetylation of high quality polyglucosamine provided by our industrial partner. These chitosan polymers have random patterns of acetylation (PA).
We can supply small quantities (1-10 mg) of fully acetylated chitin oligomers (GlcNAc dimer to hexamer) and fully deacetylated chitosan oligomers (GlcN dimer to decamer), as well as very small quantities (1 mg) of fully defined partially acetylated chitosan oligomers (paCOS, of some but not all patterns of acetylation). Chitosan oligomers are produced by partial depolymerisation of high-quality polyglucosamine provided by our industrial partner, followed by size exclusion chromatography. Chitin oligomers are produced either by chemical re-N-acetylation of the chitosan oligomers, or de novo by E. coli cell factories expressing a chitin synthase gene. paCOS are produced from chitin or chitosan oligomers by regio-selective enzymatic de- or re-N-acetylation followed by chromatographic purification. All oligomers are characterized by mass spectrometry.
Chitin and Chitosan Modifying Enzymes
We can supply small quantities of purified recombinant chitinases, chitosanases, and chitin de-N-acetylases with different well-defined subsite specificities and regio-selectivities which can be used e.g. for the production of well-defined chitin and chitosan oligomers. The enzymes are produced in E. coli, some of the deacetylases as fusion proteins, and purified using an affinity tag. Subsite specificities and regio-selectivities are characterized by mass spectrometric analyses of the products of enzymatic digestions of defined substrates.
We can supply small quantities of chitin and chitosan specific ‘lectins’ engineered from chitinases and chitosanases by fusing either their substrate binding domains or their inactivated hydrolytic domains to different fluorescent tags such as GFP, e.g. for the cytochemical localization of chitin and chitosan. The fusion proteins are produced in E. coli and carry additional tags for purification. Binding specificities are determined by dot blot analyses.