Abstract: After protection of amine group, chitosan reacted with 4-acetoxy-benzoate chloride to form a ester, and the ester was reacted with hydrazine hydrate to be deprotected, para-hydroxybenzoate chitosan ester was obtained. Under optimum reaction conditions, esterification degree of para-hydroxybenzoate chitosan ester was 130%, and yield reached 80%. IR spec- trum showed the ester bond was formed between para-hydroxybenzonic acid and chitosan. Water solubility of the ester was slightly better than heptyl para-hydroxybenzoate, but alcohol solubility was greatly improved. The antimicrobial activity for Staphyloccus aurueus and Escherichia coli was better than heptyl para-hydroxybenzoate and much better than chitosan.

Key words: para-hydroxybenzoate chitosan ester, antimicrobial activity, characterization