where chitin and chitosan were equally effective as antimicrobial
agents. This suggests that the gram-negative strains P.
aeruginosa ATCC 27853 and P. melaninogenica are more resistant to
antimicrobial agents. Even chitosan was not as effective as shown
by the slightly higher optical densities (i.e. compare Figs. 11and 12
with Figs. 7e10).