Kinetic Properties and Role of Bacterial Chitin Deacetylase in the Bioconversion of Chitin to Chitosan
Hanaa M. Hegab,
Samuel M. Hudson.
Chitin is an extremely insoluble material with very limited industrial use; however it can be deacetylated to
soluble chitosan which has a wide range of applications. The enzymatic deacetylation of various chitin samples was investigated
using the bacterial chitin deacetylase (CDA), which was partially purified from Alcaligenes sp. ATCC 55938
growth medium and the kinetic parameters of the enzyme were determined. Also, the efficiency of biocatalyst recycling
by immobilization technique was examined. CDA activity reached its maximum (0.419 U/ml) after 18 h of bacterial cultivation.
When glycol chitin was used as a substrate, the optimum pH of the enzyme was estimated to be 6 after checking a
pH range between 3 and 9, while the optimum temperature was found to be 35°C. Addition of acetate (100 mM) in the assay
mixture resulted in 50% loss of enzyme activity. The Km value of the enzyme is 1.6 × 10-4 µM and Vmax is 24.7 µM/min. The average activity of CDA was 0.38 U/ml for both of immobilized and freely suspended cells after 18 h of
bacterial growth. Some related patents are also discussed here.
Keywords: Chitin deacetylase, phylogenetics, chitin, chitosan, kinetics, biopolymers, immobilization.
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