Shahriar Osfouri

Nowadays, for economic and environmental reasons, the use of biopolymers is considered. The purpose of this research is to convert shrimp waste into chitin polymer and to investigate the important factors in the production of this biological polymer. For this purpose, green tiger shrimp shells from the Persian Gulf, two microorganisms Bacillus licheniformis, and Lactobacillus Plantarum were used. The study of time in the fermentation of microorganisms shows that deproteinization in 3 days and demineralization in 4 days have the highest amount. In addition, in comparing two commercial and non-commercial cultivation environments, it was found that the use of a non-commercial cultivation environment has a higher efficiency in addition to being economical. After that, the optimization was done using the response surface method (RSM) of central composite design (CCD) and resulted in 90.4% deproteinization and 92.69% demineralization, which is close to the value predicted by the software. In the next step, product characterization was done. FTIR spectrum shows that the product has peaks like commercial chitin. Also, the degree of acetylation of the extracted chitin was 73%, which is consistent with commercial chitin. Microfiber and porous structure were observed in the scanning electron microscope (SEM) images of the product. In X-ray diffraction (XRD) patterns, four peaks were observed at 2θ=9/16°,18/9°,20/18°,23/06°, which are the same as commercial chitin. In addition, the crystallinity index (CrI) of extracted chitin was calculated as 93.9%. Thermal gravimetric analysis (TGA) showed that the thermal stability of extracted chitin was close to the thermal stability of commercial chitin.