Hydrolyzes the N-acetamido groups of N-acetyl-D-glucosamine polymers in chitin to form chitosan and acetate (PubMed:15555935, PubMed:7592838, PubMed:8987657, PubMed:9373940, PubMed:16232493, PubMed:16878976). May play a role in evasion of the host immune response; plant chitinases liberate chitin molecules from the fungal cell wall which act as elicitors of the plant immune response, deacetylation of the liberated chitin neutralizes elicitor activity (PubMed:8987657, PubMed:10913295). [(1->4)-N-acetyl-beta-D-glucosaminyl](n) + n H2O = n acetate + chitosan Some evidence supports a zinc cofactor. kcat is: 8.52 sec(-1) with GlcNAc(2) as substrate (at 45 degrees Celsius and pH 8.5), 11 sec(-1) with GlcNAc(2) as substrate (at 30 degrees Celsius and pH 8.5), 5.94 sec(-1) with GlcNAc(3) as substrate (at 45 degrees Celsius and pH 8.5), 1.53 sec(-1) with GlcNAc(3) as substrate (at 37 degrees Celsius and pH 7), 6 sec(-1) with GlcNAc(3) as substrate (at 30 degrees Celsius and pH 8.5), 96.9 sec(-1) with GlcNAc(4) as substrate (at 45 degrees Celsius and pH 8.5), 7 sec(-1) with GlcNAc(4) as substrate (at 30 degrees Celsius and pH 8.5), 7 sec(-1) with GlcNAc(5) as substrate (at 30 degrees Celsius and pH 8.5), 5.4 sec(-1) with GlcNAc(6) as substrate (at 30 degrees Celsius and pH 8.5). Optimum pH is 8 (PubMed:15555935). Optimum pH is 8.5 (PubMed:7592838). Optimum pH is 11-12 (PubMed:8987657). Optimum temperature is 60 degrees Celsius (PubMed:15555935, PubMed:8987657). Optimum temperature is 50 degrees Celsius (PubMed:7592838). Monomer. N-glycosylated. Recombinant chitin deacetylase could be used to produce chitosan oligomers or polymers from chitin, this reaction is currently achieved by thermochemical alkaline deacetylation. Due to its properties, chitosan has many biological and industrial applications such as the production of films or fibers. Belongs to the polysaccharide deacetylase family.