Characterization of chitosan extracted from Mealworm Beetle (Tenebrio molitor, Zophobas mono) and Rhinoceros Beetle (Allomyrina dichotoma) and their antibacterial activities

Abstract

Chitin was isolated from the larvae, adult, and superworm of Mealworm Beetle and the larvae, pupa, and adult of Rhinoceros Beetle by deproteinization and demineralization. Chitin yields were 4.60, 8.40, and 3.90% in the larvae, adult, and superworm of Mealworm Beetle and 10.53, 12.70, and 14.20% in the larvae, pupa, and adult of Rhinoceros Beetle, respectively. Subsequently, chitosan was obtained by deacetylation of chitin extractions from all stages of both beetle species, and its yields from chitin were 80.00, 78.33, and 83.33% in the larvae, adult, and superworm of Mealworm Beetle, and 83.37, 83.37, and 75.00% in larvae, pupa, and adult of Rhinoceros Beetle, respectively. The Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis of the chitosan from the two insect species showed the similar structural characteristics as those of commercial chitosan. Chitosan from the Mealworm Beetle showed about 1 mm inhibition zones against Bacillus cereus, Listeria monocytogenes, and Escherischia coli, and a 2 mm inhibition zone against Staphylococcus aureus in antimicrobial activity test.