Rapid and efficient extraction of chitin and chitosan for scale-up production: Effect of process parameters on deacetylation degree and molecular weight.

Chitin and chitosan have been successfully produced, from Moroccan shrimp shells, using the microwave technology. This efficient extraction method of chitin and chitosan was evaluated and demineralization, deproteinization and deacetylation steps were investigated. The effect of the reaction time, the HCl and the NaOH concentration, at different powers (90 W, 160 W, 350 W, 500 W and 650 W) was studied. The results shown that a chitosan with low degree of acetylation has been extracted using 50% of NaOH solution, at power range 500-650 W, and the deacetylation reaction was more than 80% completed after 10 min. Microwave assisted extraction allowed to produce chitosan with medium and high molecular weight (300-360 kDa). Chitin deacetylation by microwave heating was more efficient than the conventional heating, and high desacetylation degree was obtained using microwave heating in just a few minutes. This technology can save huge amount of energy when implemented on industrial scale, it's a highly economical extraction method. By this technology, we have successfully produced the chitosan CTS with low NaOH concentration (30%), which allows to avoid manipulating an extremely high concentration of a corrosive substance, especially at industrial scale. Chitosan CTS has a degree of acetylation of 23.4% and a molecular weight of 165 kDa.