Effect of mutations in csnN106 gene and S. lividans host on chitosanase production. Chitosanase activity was assayed in supernatants sampled from 16 h cultures. Media: M14 M with 0.5% mannitol (empty columns) or M14 M with 0.125% GlcN and 0.375% chitosan oligomers (filled columns). Data and error bars are the mean of three experiments. ** P ≤ 0.01, * P ≤ 0.05 obtained with an unpaired t test (GraphPad Prism version 5.00 for Windows; GraphPad Software, San Diego, CA). The table lists the genotypes of strains for each pair of columns. Variants of csnN106 gene were introduced in one copy per genome via an integrative vector. Symbols: WT: wild type; Δ: ΔcsnR mutant host; M: mutated palindromic box; Ph: phage-type promoter. The induction ratio represents the chitosanase activity of culture induced with GlcN and chitosan oligomer divided by the activity of culture in mannitol medium.