Enzymatic synthesis surfactants

Microemulsions or reverse micelles are composed of enzyme-containing, surfactant-stabiHzed aqueous microdroplets in a continuous organic phase. Such systems may be considered as a kind of immobilization in enzymatic synthesis reactions. 

Also the impact of various reaction parameters on enzymatic synthesis of amide surfactants from ethanolamine and diethanolamine has been studied, although the possibilities of acyl migration are not investigated. However, it was found that the selectivity of the reaction depended on the solubility of the product in the solvent used, and that the choice of solvent was critical to obtain an efficient process [17]. 

Among the aldonolactone-based surfactants are aldonolactone-linked fatty esters which have been prepared by selective acylation of unprotected aldono-1,4-lac-tones or aldono-1,5-lactones, One of the first reported examples of this type of surfactant was applied to the enzymatic synthesis of 6-0-aUcanoylgluconolactones [35], Thus, 6-0-decanoyl- and 6-0-dodecanoyl- derivatives (21a and 21b, respectively, Scheme 8) were obtained in 26-27% yield by esterification of glucono-1,5-lactone (1) at C-6 with the corresponding 2,2,2-trichloroethyl carboxylate in the presence of porcine pancreatic lipase (PPL) as catalyst. Compounds 21a,b are soluble in water at 90-96°C but precipitate when cooled to 30-37°C, NMR and GC-MS analysis after dissolution and precipitation indicated the presence in the mixture of compound 21b, the glucono-1,4-lactone-derived ester 22, and the... 

Figure 10.3 Enzymatic synthesis of poly(adenylic acid) in self-reproducing oleate liposomes (redrawn from Walde et al., 1994a). (a) The ADP penetrates (sluggishly) the liposome bilayer, (b) in the presence of polynucleotide phosphorylase, ADP is converted in poly(A), which remains entrapped in the liposome, (c) Polycondensation of ADP goes on simultaneously with the self-reproduction of liposomes (A is the membrane precursor, oleic anhydride, which, once added, induces the self-reproduction of liposomes S, surfactant, in this case oleate, which is the hydrolysis product of A on the bilayer E is polynucleotide phosphorylase).

E.N. Vulson, Enzymatic Synthesis of Surfactants, in Surfactants in Lipid Chemistry, ed., J.H.P. Tyman, Royal Society of chemistry, Cambridge, 1992. 

The enzymatic synthesis of polyphenols was carried out not only in the monophasic solvents but in interfacial systems such as micelles, reverse micelles, and biphasic and Langmuir trough systems, p-Phenylphenol was polymerized in an aqueous surfactant solution to give the polymer with a narrower molecular weight distribution in comparison with that obtained in the aqueous 1,4-dioxane.20... 

VuHson, E., Enzymatic synthesis of surfactants, in Novel Surfactants Preparation, Applications, and Biodegradability, Hohnberg, K., Ed., Surfactant Science Series, Vol. 74, Marcel Dekker, New York, 1998, 279-300. 

Besides polyanions such as SPS, anionic surfactants were able to provide the negative charges needed to template the formation of electrically conductive PANI. Indeed, micelles of sodium dodecylbenzensulfonate (SDBS) were used successfully as templates to induce the formation of linear and electrically conductive PANI [38]. On the other hand, cationic and non-ionic surfactants did not provide the negative charges and low pH environment needed for the synthesis of conducting PANI, as expected. Using a similar approach, dodecyl dipheny-loxide disulfonate (DODD) was used as a bifunctional template for the enzymatic synthesis of PANI [39]. UV-Vis and electrical conductivity studies showed that the electrically-conducting form of PANI was only obtained above the critical micellar concentration (CMC) of DODD. The bifunctional nature of the DODD provided... 

Maugard T, Remaud-Simeon M., Petre D., Monsan P., Enzymatic synthesis of glycamide surfactants by amidification reaction, Tetrahedron, 53(14), 1997, 5185-5194. 

In the pharmaceutieal area, the reaction of oleic acid catalyzed by lipase is used for the production of monoolein and carbohydrate fatty aeid esters, compounds with emulsifiers and surfactant properties (Wang et al., 2013 Abdulmalek et al., 2012). Another important surfactant produced is the fatty acid ester of vitamin C (Stojanovic et al., 2013). Enzymatic synthesis of aseorbyloleate is very attractive, as well as surfactants, which have high antioxidant potential (Viklrmd Alander Hult, 2003). Due to biological... 

Immobilized lipase showing high catalytic activity toward the enzymatic synthesis of polyesters was demonstrated (178). Only a small amoimt of immobilized lipase PF adsorbed on a Celite was effective for the polymerization of lactones. The catalytic activity was further enhanced by the presence of a sugar or PEG at the immobilization. Surfactant-coated lipase efficiently catalyzed the ring-opening polymerization of lactones in organic solvents, in which the modified enz5mie was soluble (179). 

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. 

However, the above does not answer the main question how can one employ isolated enzymes for the preparation of surfactants In fact, the answer is simple Use hydrolytic enzymes in nonaqueous media. Indeed, many hydrolytic enzymes, such as lipases, proteases, and glycosidases, available in large quantities, are very robust and inexpensive, and do not require any cofactors to manifest their catalytic activity. As any other catalyst, enzymes cannot influence the equilibrium of a chemical reaction and therefore the removal of water from the reaction medium forces them to work in reverse, i.e., to synthesize a chemical bond rather than to break it. Consequently, there is a principal difference between microbial and enzymatic synthesis of surfactants regarding the type of enzymes involved and the reaction medium. The former is a biosynthetic process catalyzed by living microorganisms and as such dependent solely on their viability, whereas the latter is an organic synthesis whereby enzymes are used as substitutes for chemical catalysts. The two approaches are complementary not only in terms of the production methods but because the surfactant structures amenable to both methodologies are quite different. 

Otero C. 2009. Selective enzymatic synthesis of N-acylated alkanolamine emulstfiers. In Hayes, D.G., Kitamoto, D., Solaiman, D.K.Y. Ashby, R.D. (editors). Bio-based Surfactants and Detergents Synthesis, Properties, and Applications. Cheunpaign, IL American Oil Chemists Society Press, pp. 299-322. 

Boyat, C., Rolland-Fulcrand, V., Roumestant, M.-L. et al. (2000) Chemo-enzymatic synthesis of new nonionic surfactants from unprotected carbohydrates. Prep. Biochem. Biotechnol., 30,... 

Clapes, P., Moran, M. C. and Infante, M. R. (1999) Enzymatic synthesis of arginine-based cationic surfactants. Biotechnol. Bioengng, 63, 333-343. 

The enzymatic synthesis of surfactants, on the other hand, is in essence a chemical reaction in which an enzyme (in a form isolated from its source or even as whole cells) replaces a conventional chemical catalyst. In contrast to the microbial surfactants mentioned above, the surfactants obtained by the use of single enzymes are simpler in structure but can be designed to have the desired physicochemical features. The scope of this chapter is limited to production of surfactants using enzymes and will not include microbial surfactants. 

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