Pretreatment of shrimp shells was investigated in order to lower the costs and to improve the sustainability of chitin production. Physical pretreatment comprising drying, grinding and sieving is attractive for the recovery of 50% of shrimp protein as a dry powder. Pretreatment of shells by shearing in acidified water results in the removal of up to 60% of the protein and a reduction of their mineral content without a decrease in the chitin yield. Both pretreatment procedures will lead to cleaner technology for chitin production, to a considerably lower need for chemicals, to useful protein by-products, and to less-contaminated industrial effluent.

Chitin and chitosan with improved characteristics were produced from shrimp shell waste preconditioned by limited decay or by treatment with 0.016 mol L −1 benzoic acid. Preconditioned shrimp shells were transparent, had a clean surface and were susceptible to demineralization and deproteinization using 0.68 mol L −1 HCl and 0.62 mol L −1 NaOH, respectively. The ash and protein residues in the final chitosan were about 0.2% and 0.4%, respectively, the viscosity was up to 7000 cps, and the solubility and transparency nearly 100%. In comparison with treatment at ambient temperature (30• C) without preconditioning, the chemical consumption, the duration of the treatment, ash and protein residues was reduced to 75-25%, whereas viscosity and absence of insolubles improved by a factor of 2-3.

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