Enzyme assisted extraction of chitin from shrimp shells (Litopenaeus vannamei)

8 BACKGROUND: Chemical chitin extraction generates large amounts of wastes and increases partial 9 deacetylation of the product. Therefore, the use of biological methods for chitin extraction is an 10 interesting alternative. The effects of process conditions on enzyme assisted extraction of chitin from 11 the shrimp shells in a systematic way were the focal points of this study. 12 RESULTS: Demineralisation conditions of 25C, 20 min, shells-lactic acid ratio of 1:1.1 w/w; and shells13 acetic acid ratio of 1:1.2 w/w, the maximum demineralisation values were 98.64 and 97.57% for lactic 14 and acetic acids, respectively. A total protein removal efficiency of 91.10% by protease from 15 Streptomyces griseus with enzyme-substrate ratio 55 U/g, pH 7.0 and incubation time 3 h i s 16 o b t a i n e d w h e n t h e particle size range is 50-25 ́m, which was identified as the most critical factor. 17 The X-ray diffraction and C NMR spectroscopy analysis showed that the lower percent crystallinity and 18 higher degree of acetylation of chitin from enzyme assisted extraction may exhibit better solubility 19 properties and less depolymerisation in comparison with chitin from the chemical extraction. 20 CONCLUSION: The present work investigates the effects of individual factors on process yields, and it 21 has shown that, if the particle size is properly controlled a reaction time of 3 h is more than enough for 22 deproteination by protease. Physicochemical analysis indicated that the enzyme assisted production of 23 chitin seems appropriate to extract chitin, possibly retaining its native structure. 24