Papain assisted preparation of chitosan: Feasibility study for candidate in-house reference material and antibacterial agent

Abstract

Chitosan preparation assisted by papain was carried out to reduce the use of chemicals in the extraction of chitosan. This research aims to modify the chitosan extraction method to be more environmentally friendly and improve the physicochemical properties. Chitosan preparation is carried out in 4 main steps which include depigmentation, demineralization, deproteination, and deacetylation. Deproteination uses papain extract with varying concentrations of 5 - 25% for 7–11 h. The results of characterization using FTIR confirmed that the chitosan preparation was successful. The characteristic FTIR spectra are shown by the presence of a wideband at 3000–3600 cm−1 from stretching vibrations of the –OH and –NH and a peak at 1500–1700 cm−1 which indicates the N–H and CO stretching vibrations of the amino group. The XRD pattern verifies the peak characteristic of chitosan at an angle of 2 theta 9.39, 19.16, 25.96, 32.31, and 34.17°. SEM-EDX imaging shows the chitosan morphology whose particle arrangement is a uniform, smooth, and non-aggregated arrangement of its particles with the main composition of chitosan consisting of carbon, oxygen, and nitrogen atoms. The optimum papain concentration of 25% and deproteination time of 7 h with a deacetylation degree of 70.83% are the recommended conditions for chitosan preparation. The extracted chitosan was confirmed to satisfy the homogeneity and stability requirements as a candidate for in-house reference material. The homogeneity test results of the MSB and MSW values obtained F-test < F-critical (2.7858 < 3.1789) and the results of ANOVA (α = 95%, df = 9) obtained F-test < F-critical (0.4466 < 4.4139). The chitosan produced is validated as a stable material with a value of | X̅i - X̅HM | < 0,3 x nIQR (0.2501 < 1.7345). The chitosan produced has antibacterial activity against P. acnes, S. aureus, K. pneumoniae, P. aeruginosa, and E. coli.