Produção de quitosana a partir da fermentação da casca de camarão.

Abstract

The shrimp shell is a by-product of the fishing industry that is virtually untapped in Brazil, although it can be used for the extraction of chitin and chitosan production, a biopolymer with wide application in the biomedical field. However, the chemical extraction steps chitin disclose to be harmful to the environment. The present research studied a fermentation process, using the Saccharomyces cerevisiae with variation of substrate concentration, for aerobic and anaerobic pathways in order to determine the most effective method for bioconversion of these food residues into high value products. The shell was characterized as the size of particles by optical microscopy technique and the minerals composition by the ash´s technique. The fermentation takes place in erlenmeyer flasks containing the medium inoculated together with the chosen substrate, where the whole process was maintained under stirring at 120 rpm, at 35 °C, for 96 hours. It was determined in this study, the composition of the shell of the Litopenaeus vannamei shrimp which is 55.3 % of mineral filler with about 60 % calcium carbonate, the protein content is 24.3 % and chitin content is 20.45 %. The yeast Saccharomyces cerevisiae has been effective in fermenting the shrimp waste, resulting in 3 % of chitin´s preservation. The aerobic fermentation, in chitin extraction process, was most effective, with about 25 % of deproteinization and 11 % of demineralization improvement in relation to the anaerobic fermentation. The amount of 5 g of the substrate in aerobic fermentation was the most representative, removing about 74 % mineral and 42 % protein. Chitosan produced by fermentation showed deacetylation degree of 77 % and more suitable staining for chitosan specifications in medical devices. The obtained chitin and chitosan show similar purity to those obtained by chemical extraction, indicating the efficient methodology developed in this work.