Biotechnologically produced chitosans with nonrandom acetylation patterns differ from conventional chitosans in properties and activities.

Chitosans are versatile biopolymers with multiple biological activities and potential applications. They are linear copolymers of glucosamine and N-acetylglucosamine defined by their degree of polymerisation (DP), fraction of acetylation (F), and pattern of acetylation (PA). Technical chitosans produced chemically from chitin possess defined DP and F but random PA, while enzymatically produced natural chitosans probably have non-random PA.

Quantification of chitosan in aqueous solutions by enzymatic hydrolysis and oligomer analysis via HPLC-ELSD.

A new method for quantitative analysis of chitosan in aqueous solution is introduced, comprising an enzyme-driven cleavage to water-soluble chitooligosaccharides (COS), N-acetylation, separation via UHPLC and detection by use of an evaporative light scattering detector (ELSD). Chitosans with different fractions of acetylation (F) and molecular weights (M) were hydrolyzed using a chitosanase/chitinase mixture. By subsequent N-acetylation with isotopically labelled acetic anhydride, COS mixtures with F = 1 were obtained allowing for chromatographic separation solely based on their degree of polymerization (DP).

A seven-membered cell wall related transglycosylase gene family in is relevant for cell wall integrity in cell wall mutants with reduced α-glucan or galactomannan.

Chitin is an important fungal cell wall component that is cross-linked to β-glucan for structural integrity. Acquisition of chitin to glucan cross-links has previously been shown to be performed by transglycosylation enzymes in , called Congo Red hypersensitive (Crh) enzymes. Here, we characterized the impact of deleting all seven members of the gene family () in on cell wall integrity, cell wall composition and genome-wide gene expression.

Robust enzymatic-mass spectrometric fingerprinting analysis of the fraction of acetylation of chitosans.

We developed a rapid and precise method to determine the fraction of acetylation (F) of unknown chitosan samples using a combination of enzymatic sample hydrolysis, isotopic labeling, and HILIC-ESI-MS analysis. Chitosans are β-(1,4)-linked, partially N-acetylated and linear polyglucosamines representing an interesting group of functional biopolymers with a broad range of applications. For a better understanding of their structure-function relationships, it is key to have sensitive, accurate structural analysis tools available to determine parameters like the degree of polymerization (DP), fraction of acetylation (F), or pattern of acetylation (P).

Enzymatic Production and Enzymatic-Mass Spectrometric Fingerprinting Analysis of Chitosan Polymers with Different Nonrandom Patterns of Acetylation.

Chitosans, a family of ß-(1,4)-linked, partially N-acetylated polyglucosamines, are considered to be among the most versatile and most promising functional biopolymers. Chemical analysis and bioactivity studies revealed that the functionalities of chitosans strongly depend on the polymers' degree of polymerization and fraction of acetylation. More recently, the pattern of acetylation ( P) has been proposed as another important parameter to influence functionalities of chitosans.

A chitin deacetylase of Podospora anserina has two functional chitin binding domains and a unique mode of action.

Chitosan is a structurally diverse biopolymer that is commercially derived from chitin by chemical processing, but chitin deacetylases (CDAs) potentially offer a sustainable and more controllable approach allowing the production of chitosans with tailored structures and biological activities. We investigated the CDA from Podospora anserina (PaCDA) which is closely related to Colletotrichum lindemuthianum CDA in the catalytic domain, but unique in having two chitin-binding domains. We produced recombinant PaCDA in Hansenula polymorpha for biochemical characterization and found that the catalytic domain of PaCDA is also functionally similar to C.

Chitosan Analysis by Enzymatic/Mass Spectrometric Fingerprinting and in Silico Predictive Modeling.

Chitosans, β-1,4-linked partially N-acetylated linear polyglucosamines, are very versatile and promising functional biopolymers. Understanding their structure-function relationships requires sensitive and accurate structural analyses to determine parameters like degree of polymerization (DP), fraction of acetylation (F), or pattern of acetylation (P). NMR, the gold standard for F analysis, requires large amounts of sample.

Chitinosanase: A fungal chitosan hydrolyzing enzyme with a new and unusually specific cleavage pattern.

The biological activities of partially acetylated chitosan oligosaccharides (paCOS) depend on their degree of polymerization (DP), fraction of acetylation (F), and potentially their pattern of acetylation (P). Therefore, analyzing structure-function relationships require fully defined paCOS, but these are currently unavailable. A promising approach for obtaining at least partially defined paCOS is using chitosanolytic enzymes.

Design and characterization of self-assembled fish sarcoplasmic protein-alginate nanocomplexes.

Macrostructures based on natural polymers are subject to large attention, as the application range is wide within the food and pharmaceutical industries. In this study we present nanocomplexes (NCXs) made from electrostatic self-assembly between negatively charged alginate and positively charged fish sarcoplasmic proteins (FSP), prepared by bulk mixing. A concentration screening revealed that there was a range of alginate and FSP concentrations where stable NCXs with similar properties were formed, rather than two exact concentrations.