Germinated Winter Wheat (Triticum aestivum L) and Buckwheat (Fagopyrum esculentum) Extract for Chitin Isolation from White Shrimp Shells

Germinated grains can be a source of low-cost protease for chitin extraction. Using crude protease from germinated grains in combination with chemicals can reduce the use of the chemicals in isolating chitin. This study aimed to determine proteolytic and chitinolytic activities of crude enzymes extracted from germinated winter wheat (Triticum aestivum) and buckwheat (Fagopyrum esculentum). The crude enzyme was applied in the deproteinization step during chitin isolation from shrimp shells. The deproteinization rate was assessed, the crude chitin yield was compared and the isolated chitins were characterized through x-ray diffraction analysis. Proteolytic activities and chitinolytic activities were detected in the crude enzymes extracted from germinated winter wheat and buckwheat as shown by clear zones in agars containing azocasein, casein, gelatin and colloidal chitin through radial diffusion study (A Diameter of clear zones). The germinated winter wheat and buckwheat extracts exhibited proteolytic activity of 0.49 U/mL and 0.46 U/mL (B Proteolytic activities of germinated winter wheat and germinated buckwheat), and chitinolytic activity of 0.074 and 0.053 U/mL, respectively (C Chitinolytic activity of germinated winter wheat and germinated buckwheat). Using winter wheat extract and buckwheat extract acted on demineralized shrimp shells exerted a deproteinization rate of 53.6±1.0% and 58.0±2.3% (D Deproteinization rate) and yielded 30.3±5.31% and 29.2±3.99% (E Crude chitin yield) crude chitin, respectively. The crystallinity index for commercial chitin, chemical-isolated chitin, wheat extract- and buckwheat extract-isolated chitin were 86.49%, 88.74%, 88.82% and 75.87% (F1 to F4 X-ray diffraction data), respectively. Buckwheat extract-isolated chitin, which was deacetylated with lower crystallinity, warrants further investigation. Crude enzymes from winter wheat and buckwheat to remove protein from shrimp shells can be a more environment-friendly method to valorize shrimp shells as a chitin source.