Facile production of chitin from shrimp shells using a deep eutectic solvent and acetic acid

High purity chitin was extracted from shrimp shells by a green, sustainable, and efficient one-pot approach using a deep eutectic solvent consisting of choline chloride and glycerol (ChCl–Gl) combined with a small amount of acetic acid. Under the conditions of an acetic acid concentration of 7.5 wt% and reaction temperature of 120 °C, the purity of isolated chitin was up to 96.1%, which was superior to that of 87.7% obtained by conventional chemical method. In addition, the viscosity-average molecular weight and crystallinity of the extracted chitin were revealed to be larger than for the latter. Moreover, the deep eutectic solvent could be recycled at least three times without losing the quality of the extracted chitin. This facile approach combining recyclable DES with a small amount of acetic acid was expected to be used for the green and sustainable production of chitin from shrimp shells.