separation of crude chitin
by centrifugation (4000rpm, 15min) and
precipitation of chitosan from the extract at pH=9,
adjusted with a 4M NaOH solution. Crude chitin
and chitosan were washed on a coarse sinteredglass
funnel with distilled water, ethanol and
acetone and air-dried at 20ºC (Synowiecki, 1997)