Amino acid-based surfactants biodegradability

Contrarily to fatty add salts (i.e., sodium laurate soap), the long-chain iV -acyl amino adds have excellent water solubility (due to the presence of additional CO-NH linkages), quick biodegradability and good lime resistance (i.e., caldum ion tolerance) [11]. The surfactant properties of pure sodium salts of iV -acyl amino acids (anionic surfactants) with different alkyl chains (saturated and unsaturated with 10-18 carbon atoms) and amino acid residues have been described and compared with those of sodium lauryl sulfate (SLS) and sodium laurate [11-14]. The authors showed that the critical micelle concentration (CMQ of the amino acid-based surfactants was lower than that of the SLS but higher than that of sodium laurate. The surface activity increased and the CMC decreased by raising the alkyl chain... 

One important milestone in our research is the design and development of new amino acid-based surfactants with antimicrobial properties, which mimic natural amphiphilic cationic peptides [42,43]. To this end, Lys and Arg derivatives of long-chain A -acyl, COO-ester, and A-alkyl amide have been prepared. In particular, the A -acylarginine methyl ester derivatives series 1 (Scheme 1) have turned out to be an important class of cationic surface active compounds with a wide bactericidal activity, high biodegradability, and low toxicity profile. We have shown that essential structural factors for their antimicrobial activity include both the length of the fatty residue (akin with their solubility and surface activity) and the presence of the protonated guanidine function [43,44]. 

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