To evaluate the effect of ammonium sulfate, different concentrations were added to production medium (0.25 to 3 g L-'). Maximum chitimse production by Aeromonas sp. JKl was formd in media with 1.5 (g L-1) ammoinum sulfate and a change from 2 to 3 (g L_,) did not bring about striking variations in the amormt of enzyme produced (Fig. 3).