Enzymatic hydrolysis of thermally pre‐treated chitin and antimicrobial activity of N,N’ ‐diacetylchitobiose

BACKGROUND: N,N’-diacetylchitobiose (GlcNAc2) is known to be highly functional and offers a wide range of applications, especially as an antimicrobial agent. In this study, a thermal pre-treatment process using steam under pressure in an autoclave, has been employed to facilitate subsequent enzymatic hydrolysis of chitin with chitinase from Streptomyces griseus. RESULTS: Pre-treatment of chitin with 0.05 M sodium acetate buffer (pH=6.0) at 121oC for 60 min, followed by enzymatic hydrolysis involving 24 h incubation, was found to be the best condition for producing the GlcNAc2. The GlcNAc2 obtained was tested regarding its antimicrobial activity against Gram-negative and Gram-positive strains and showed minimum inhibitory concentrations (MIC) at 5 and 10% w/v against Escherichia coli K-12 and Listeria monocytogenes 10403S, respectively. CONCLUSION: The extent of swelling and crystallite size of chitin increased with the pre-treatment residence time, and enhanced the rate of subsequent hydrolysis using chitinase.