The stock solution (1%, w/v) of chitosan was prepared
by dissolving chitosan in 0.5% (v/v) glacial acetic acid as
described by Benhamou et al. (1998). The pH of stock solution was adjusted to 5.6 by 1N NaOH and it was sterilized
with autoclave (120°C, 20 min) prior to use in the assays.