Crustacean shell bio-refining to chitin by natural deep eutectic solvents

Abstract

This study provides a complete evaluation of a sustainable zero-waste process for the recovery of added value biomaterials from the abundant shrimp shell biomass waste using natural deep eutectic solvents (NADES). The process parameters for the fractionation of α-chitin, minerals and protein was followed using on-line measurements. Furthermore, the quantitative analysis of isolated chitin, minerals and solvent waste streams were examined. The dominant fractionation mechanisms are explained through the analysis of the liquid and solid fractions. Four of the most promising, and commercially available, NADES consisting on mixtures of Choline Chloride-Lactic Acid (CCLA), Choline Chloride-Malonic Acid (CCMA), Choline Chloride-Urea (CCUR) and Choline Chloride-Citric Acid (CCCA), were tested. The highest chitin extraction yield obtained was < 90% using CCLA, leading to purity higher than 98%. Moreover, it is possible to recycle this particular NADES several times, while having no loss in the shrimp shell fractionation capability.