Catalyzes the hydrolysis of short-chain aliphatic amides to their corresponding organic acids with release of ammonia. Enables the organism to use acetamide as both carbon and nitrogen source. Also exhibits in vitro acyl transferase activity, transferring the acyl moiety of short-chain amides to hydroxylamine to form hydroxamates. a monocarboxylic acid amide + H2O = a monocarboxylate + NH4(+) Homohexamer. Belongs to the carbon-nitrogen hydrolase superfamily. Aliphatic amidase family.