An Alternative to Conventional Antibiotics - The Antimicrobial Properties of Deacetylated Chitin Extracted from Gongronella Butleri: A Research Protocol

Abstract

Antimicrobial resistance (AMR) is a growing threat to global public health and development. It is estimated that AMR was directly responsible for 1.27 million deaths worldwide in 2019. Due to the superfluous use of antibiotics, AMR is increasingly widespread, and bacterial infections are becoming more difficult to treat. Chitin is a potential alternative that has demonstrated antimicrobial properties. Most commonly extracted from insects and crustaceans, chitin can also be found in the cell walls of fungi. In previously performed experiments, the results supported the hypothesis that chitin derived from crustaceans and insects displayed antimicrobial properties. Due to the different chemical composition and attributes of fungal chitin, this study will explore whether fungal chitin also displays antimicrobial properties. In this experiment, chitin will be extracted from Gongronella butleri fungus and will be deacetylated into two degrees of deacetylation (70% and 90%) to form chitosan in liquid form. Chitosan easily interacts with the bacterial cell wall and inhibits the formation of the cell wall. The chitosan will then be added to two bacterial cultures, Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative), and the diameter of inhibition will be assessed to determine the efficacy of chitosan as an antimicrobial agent. The control Petri dishes will contain the most common antibiotic used for each bacterial culture (penicillin for S. aureus and streptomycin for E. coli). The results will be analyzed using a two-way Analysis of Variance (ANOVA) test. It is anticipated that chitosan will inhibit the growth of both bacterial cultures. It is expected that the low-molecular-weight chitosan will be more effective against E. coli and the high-molecular-weight chitosan will be more effective against S. aureus. If the diameter of inhibition of the bacterial cultures with chitosan is equal to or greater than the diameter of inhibition of the control, then it can be concluded that chitosan is an effective antimicrobial agent. The results will indicate whether fungal chitin has antimicrobial properties and can be used as an alternative to antibiotics. This experiment can be expanded, to test how metal salts, temperature, pH, and varying degrees of deacetylation influence the antimicrobial properties of chitin.