Paper from our collaborators in Vietnam: „Preparation of water soluble hydrochloric chitosan from low molecular weight chitosan in the solid state“

Today, a paper from a team around Prof. Trang Si Trung from Nha Trang University in Vietnam, in which they describe the solubilisation of chitosan using gaseous HCl, converting it into chitosan hydrochloride, appeared in the „International Journal of Biological Macromolecules“. Chitosan polymers are insoluble in water unless it is slightly acidified, whereas chitosan salts are readily soluble. Chitosan salts are prepared by dissolving chitosans in dilute acid, then drying them using expensive and energy-intensive freeze drying or spray drying. The new method using HCl gas yields a dry chitosan hydrochloride salt that is readily soluble in water. Both the original chitosan polymer and the resulting chitosan hydrochloride were extensively analysed, including state-of-the-art 1H-NMR for the determination of the degree or fraction of acetylation, and HP-SEC-RID-MALLS for the determination of molecular weights and dispersities, resulting in Figures 5 and 6 as well as Table 3 in the paper. These analyses were initially performed by Dr. Nour Eddine El Gueddari and were perfected later in the revision stage by Anna Niehues and Jasper Wattjes, all from our group. Increasingly, Vietnam is being established as a commercial producer of high quality chitosans, and the method developed allows the industry scale production of chitosan hydrochloride in a dry form that can easily be shipped, e.g. to Europe where chitosan hydrochloride is recognized as a “basic substance” that may be used in agriculture without the need for lengthy and costly registration procedures.