New Chitin, Chitosan, and O-Carboxymethyl Chitosan Sources from Resting Eggs of Daphnia longispina (Crustacea); with Physicochemical Characterization, and Antimicrobial and Antioxidant Activities
2014
Kaya, M., Department of Biotechnology and Molecular Biology, Aksaray University, Aksaray, Turkey | Cakmak, Y.S., Department of Biotechnology and Molecular Biology, Aksaray University, Aksaray, Turkey | Baran, T., Department of Chemistry, Faculty of Science and Letters, Aksaray University, Aksaray, Turkey | Asan-Ozusaglam, M., Department of Biotechnology and Molecular Biology, Aksaray University, Aksaray, Turkey | Mentes, A., Science and Technology Application and Research Centre, Aksaray University, Aksaray, Turkey | Tozak, K.O., Department of Chemistry, Faculty of Science and Letters, Aksaray University, Aksaray, Turkey
The paper describes the isolation and characterization of chitin and chitosan from Daphnia longispina resting eggs harvested from a reservoir. Resting eggs are fertilized eggs that are encased in chitinous shells called 'ephippia' and which ensure the survival of the Daphnia population in adverse conditions. The chitin-content of D. longispina resting eggs was found to be 23 ~ 25% and the chitosan (having a 70 ~ 75% deacetylation degree) yield of the chitin was 76 ~ 77%. This high chitin-content indicates that D. longispina resting eggs can be exploited as a chitin source. The structure and thermal properties of chitin, extracted from D. longispina resting eggs, were characterized by employing Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction and scanning electron microscopy. The crystallinity of the chitin was found to be very low (48%). Physicochemically-characterized chitosan and the produced O-carboxymethyl chitosan were tested for their antimicrobial and antioxidant activity. It has been observed that chitosan displays antimicrobial activity against all pathogenic bacteria, whereas O-carboxymethyl chitosan only exhibits inhibition activity against L. garvieae, L. Monocytogenes ATCC 7644, Y. enterocolitica NCTC 11175 and S. aureus ATCC 25923. In a free radical scavenging activity assay, the IC 50 values of chitosan, O-carboxymethyl chitosan and butylated hydroxytoluene were found to be 23.01, 56.43 and 0.05, respectively. The ferric-reducing power of O-carboxymethyl chitosan ( EC 50 = 8.30) i 8.30) indicated higher activity than chitosan ( EC 50 = 10.12). 10.12).
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