Antimicrobial activity and biodegradability of N-alkylaldonamides

Abstract

A number of N-alkylaldo-namides, i.e., nonionic saccharide-based surfactants such as N-alkyl-N-methylgluconamides, N-alkyl-N-methyllactobionamides and N-alkyl-N,N’-bis[(3-D-aldonamidopro-pyl]amines were evaluated for environmental responses. All the N-alkylaldonamides were screened for antimicrobial activity against selected gram-positive (Staphylococcus aureus PCM 1944, Sarcina lutea PCM 1947, Bacillus subtilis PCM 1949, gram-negative (Escherichia coli PCM 2057, Serratia marcescens PCM 549, Pseudomonas putida PCM 2124) bacterial strains and some fungi (Saccharomyces cerevisiae, Penicillum citrinum, Aspergillus niger). It was generally recognized that the compounds tested were completely inactive towards fungi. N-Alkyl-N-methylgluconamides and N-alkyl-N-methyllactobionamides were practically inactive towards the bacteria studied. On the other hand, dicephalic saccharide-based surfactants were active against gram-positive cocci, much more strongly than the N-alkyl-N-methylaldonamides. Using the closed-bottle test (OECD guideline 301D), the biodegradability of these surfactants was determined. N-Alkyl-N-methyl-aldonamides may be considered to be readily biodegradable by activated sludge. The dicephalic surfactants studied showed slower biodegradation rates and they may be considered to be inherently biodegradable. Members of this class of saccharide surfactants exibit biological properties needed for environmental acceptance.