Extraction, characterization and comparison of chitins from large bodied four Coleoptera and Orthoptera species

Abstract

Chitins were extracted from large insect species of order Coleoptera (Lucanus cervus (Linnaeus, 1758) (Lucanidae) and Polyphylla fullo (Linnaeus, 1758) (Scarabaeidae) and order Orthoptera (Bradyporus (Callimenus) sureyai Ünal, 2011) (Tettigonidae) and Gryllotalpa gryllotalpa (Linnaeus, 1758) (Gryllotalpidae)) for the first time. Fourier Transform Infrared Spectrometry (FT-IR) confirms that isolation of chitin is successful. Yields of chitins on dry basis from P. fullo, L. cervus, G. gryllotalpa and B. (C.) sureyai are 11.3%, 10.9%, 10.1% and 9.8% respectively. Thermogravimetric Analysis (TGA) showed a variety of thermal stability of chitin samples from 614 °C to 748 °C with a small percent of ash. X-ray diffraction (XRD) data showed a crystallinity index percent from 80.6% to 85.2%. Scanning Electron Microscope (SEM) was examined for surface characterization determining as fibrous and porous for all species and changes from nm scales to μm scales. Elemental analysis has been applied to determine the elemental composition of chitin and nitrogen percent was relatively low for all specimens than expected. It is detected that examined insects have α-chitin form from XRD and FT-IR data. If these species can be grown in the laboratory, adults of them could be accepted as promising alternative chitin sources without negative effects on biodiversity.