Amino acid-based surfactants synthesis

Amino acid-based surfactants are derived from simple amino acids or mixed amino acids from synthesis or protein hydrolysates. They are composed of amino acid as the hydrophilic part and a long hydrocarbon chain as the hydrophobic part. The hydrophobic chain can be introduced through acyl, ester, amide, or alkyl linkage. Interest in amino acid surfactants is not new, as shown by early work in the area. In 1909, Bondi performed the first research on the introduction of a hydrophobic group to obtain A-acylgiycine and A-acyla-lamine [18], Subsequent work in this area focused on A-acylamino acids, as reported by Funk [19], Izar [20], Karrer [21], Staudinger and Becker [22],... 

The authors are very grateful to Prof. Nakanishi of Okayama University for providing information and discussions on enzymatic synthesis of acylated amino acids. The experiments on synthesis of amino acid-based surfactants referred to in the text are now under way in collaboration with Prof. Nakanishi, supported partially by a Grant-in-Aid from the Program for Promotion of Basic Research Activities for Innovative Bioscience in Japan. The authors wish to thank Prof. Shimizu of Tokyo University and Prof. Kato of Yamaguchi University for discussions relating to the text. 

Soo EL, SaUeh AB, Basri M, Rahman RNZRA Kamaruddin K. 2003. Optimization of the enzyme-catalyzed synthesis of amino acid-based surfactants from palm oil fractions. Journal of Biosdence and Bioengineering 95(4) 361-367. 

US Department of Energy. 1999. The Technology Roadmap for Plant /Crop-Based Renewable Resources 2020. wwwl.eere.energy.gov/biomass/pdfs/technology roadmap.pdf (accessed 17 December 2010). VaUvety R, Jauregi P, GiU 1 Vulfson E. 1997. Chemo-enzymic synthesis of amino acid-based surfactants. 

Figure 8.6 Enzymatic synthesis of amino acid-based surfactants (I) linear, (II) dimeric or gemini and (III) diacylglycerol amino acid conjugates. The amino acid can be coupled to an alkyl chain via an ester or an amide linkage.

VaUvety R, GUI IS Vulfson EN. 1998. AppUcation of enzymes to the synthesis of amino acid-based bola and gemini surfactants. Journal of Surfactants and Detergents 1(2) 177-185. van Rantwijk F, Woudenberg-van Oosterom M Sheldon RA. 1999. Glycosidase-catalyzed synthesis of alkyl glycosides. Journal of Molecular Catalysis B Enzymatic 6(6) 511-532. 

Sakamoto, K. (2001) Current market developments and trends in amino acid- and protein-based surfactants, in Protein-Based Surfactants, Synthesis, Physicochemical Properties and Applications (eds I. A. Nnanna and J. Xia), Marcel Dekka, New York, pp. 261-280. 

Doll, K.M., Erhan, S.Z., 2009. Polyol and amino acid-based biosurfactants, builders, and hydrogels. In Hayes, D.G., Kitamoto, D., Solaiman, D.K.Y., Ashby, R.D. (Eds.), Biobased Surfactants and Detergents. Synthesis, Properties, and Applications. AOCS Press, Urbana, Illinois, pp. 425-448. 

Although this book is focused primarily on the synthesis and application of PBS from renewable sources or waste products, some naturally occurring PBS will also be discussed briefly. Some of these naturally occurring PBS have found applications in the pharmaceutical and personal care industries. Also, this book is primarily about amino acid- and peptide-based surfactants, two types of PBS that are discussed in some detail in the following sections. 

The preparation of surfactant molecules in the laboratory is often achieved by the method of modular synthesis [7,8]. This means that the molecule is considered as an assembly of subunits called moduli. In this way we can distinguish in natural surfactants bi- or trimodular structures, as shown in Scheme 1. Based on this principle, the synthetic approaches and strategies are variable. The amino acid by itself may or may not constitute the hydrophilic modulus alternatively, it may play the role of the junction modulus or that of an anchor unit for the hydrophobic group attached to it via a C-C bond, depending on its specific structure. 

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