COMPARATIVE STUDY OF PHYSIOCHEMICAL AND ANTIMICROBIAL PROPERTIES OF ADULT COCKROACHES-EXTRACTED CHITOSAN

Abstract

Drug resistance, caused by the overuse of antimicrobial drugs, has necessitated the development of new strategies for treatment. Insect species, the largest in the animal kingdom, can serve as a suitable source for the production of chitosan, which is an important immune system stimulator. We investigated the physicochemical and antimicrobial properties of chitosan extracted from adult cockroaches of Blattella germanica (Dictyoptera: Ectobiidae) and Periplaneta americana (Dictyoptera: Blattidae). The cuticle of the adult insects was dried and grounded. Subsequently, samples were deproteinized, demineralized, and then deacetylated using NaOH. The FTIR spectra were employed to evaluate the functional groups of chitosan. Antimicrobial action was investigated against Gram-positive bacteria (Staphylococcus epidermidis and Enterococcus faecalis) and Gram-negative bacteria (Klebsiella pneumoniae and Proteus mirabilis). The results indicated that the chitosan ratios in American and German cockroaches were 5.80 and 2.95%, respectively, for every 3 g of powder obtained from each sample.  Additionally, the deacetylation degree (DD) of chitin in German and American samples was 31.5% and 36.8%, respectively. At a 1% concentration, German cockroach chitosan exhibited significant bactericidal activity against K. pneumoniae compared to other concentrations, while the 1% concentration of American cockroach chitosan had the highest efficacy against P. mirabilis compared to other concentrations. This study demonstrates that the chitosan concentration and insect species have an impact on the bactericidal action of chitosan.