Biobased surfactants

Esters represent an important class of chemical compounds with applications as solvents, plasticizers, flavors and fragrances, pesticides, medicinals, surfactants, chemical intermediates, and monomers for resins. Recently, esters of amino acids have attracted attention regarding their use as biobased surfactants with excellent adsorption and aggregation properties, low toxicity, and broad biological activity. 

Balachandran, V.S., Jadhav, S.R., Pradhan, P Carlo, S.D. and John, G. (2010) Adhesive vesicles through adaptive response of a biobased surfactant. Angewandte Chemie International Edition, 49 (49), 9509-9512. 

Biobased surfactants are surface-active compounds, which are produced extra-cellularly by microorganisms from carbon sources such as hydrocarbons, crude oil, glucose, sucrose, glycerin, olive oil or fructose. Biobased surfactants have special advantages over their chemically manufactured counterparts because of lower toxicity, biodegradability, and effectiveness at extreme conditions. In addition, they possess surface-active properties differing in many cases from synthetic surfactants. 

Several biobased surfactants have been reported to have manifold biological activities covering antibiotics, fungicidal, insecticide, antiviral and antitumoral agents, immunomodulators or specific toxins, and enzyme inhibitors [30]. 

Biobased surfactants are typically divided into glycolipids, lipopeptides, phospholipids, functionalized fatty acids, and polymeric biosurfactants. Typical representatives of these groups are rhamnoUpids, trehaloselipids, sophoroselipids, cellobioselipids, surfactin, liposan, and emulsan. 

Although the interest in biobased surfactants has globally increased considerably in recent years, they still compete with difficulty against the chemically synthesized compounds on the surfactant market, due to their high production costs. 

Hayes DG. Biobased-surfactants overview and industrial state-of-the-art. In Hayes DG, Kitamoto D, Solaiman DKY, Ashby RD, editors. Biobased surfactants and detergents. Urbana AOCS Press 2009. p. 3-25. 

Though with lower impact on the main physicochemical properties, the regiochemistry can also influence the behaviour of the products (Fig. 2). In keeping with the interesting example of sucrose esters, which are historical biobased surfactants developed in the middle of the 20 century and used as food or cosmetic emulsifiers, it was found that... 

During the past few decades a substantial amount of effort has been devoted to the development of renewable products that are readily biodegradable, such as bioplastics for solid disposable articles, packaging applications, biobased surfactants, co-builders and bleaching activators for detergency applications and starch and sugar based products for the cosmetics industry. ... 

Since 2008, the price for crude petroleum has decreased due to the economic recessions in many countries worldwide, which has led to decreased demand, leading to a wane in the interest for bio-based surfactants. However, petroleum prices are expected to iuCTease again in the near future as economic recovery progresses. Therefore, it is anticipated that biobased surfactants will be economically viable in the near future. 

Figure 10.1 Process flow diagram of a possible oleochemical biorefinery to produce targeted chemicals, materials, and fuels (underlined), indicating potential chemical intermediates useful for synthesis of biobased surfactants (italicized).

Figure 10.3 Molecular structure of biobased surfactants that can be produced via bioprocessing.

Table 10.1 Enzymes used for bioprocessing of biobased surfactants, and the reactions and products they catalyze. 

Pinzon NM, Zhang Q, Koganti S Ju L-K. 2009. Advrmces in bioprocess development of rhamnoUpid and sophoroUpid production. In Hayes, D.G., Kitamoto, D., Solmman, D.K.Y. Ashby, R.D. (editors). Biobased Surfactants and Detergents. Champaign, IL American Oil Chemists Society Press, pp. 77-105. 

In all the above examples, there is no question about the bio-based origin of the surfactant, its biocompatibility and its ability to quickly biodegrade. However, all these attributes are necessary but not sufficient to answer the question of sustainability. Currently there are questions being raised about the sustainability of growing crops of palm oil in southeast Asia which are currently used as feedstock for soaps and other biobased surfactants. Some of the issues being considered are reduction in biodiversity, deforestation, impact of fertilizers and pesticides, and reduction in the natural habitat for numerous species [1], With respect to the production of biosurfactants by microorganisms (e.g. rhanmoUpids and sophorolipids), valuable carbon sources such as glucose are often used. These carbon sources are expensive, and are also a food source for animals and humans. 

Quadri, G., Chen, X., Jawitz, J. W. et al. (2008) Biobased surfactant-like molecules from organic wastes the effect of waste composition and composting process on surfactant properties and on the ability to solubilize tetrachloroethene (PCE). Environ. Sci. Technol., 42 (7), 2618-2623. 

Group, and a member of the AOCS Books and Speeial Publications Committee. Doug has published over 65 articles in peer-reviewed publications, 15 book chapters, and one edited book. Doug s research interests include applied biocatalysis, biobased surfactants and polymers, soft matter colloidal systems, and small-angle scattering methods. 

By ethoxylation of natural fatty alcohols from vegetable oils with biobased ethylene oxide fiolly biobased nonionic fatty alcohol polyglycol ether surfactants can be manufaaured... 

In an alternative strategy starting from isomaltulose, new carbohydrate containing acrylates were recently prepared by aqueous Baylis-Hillman reaction of a-D-glucosylo>grmethylfurfural 36 with various acrylates was reported (Scheme 14). This new approach towards totally biobased functional compounds (potential monomers, surfactants) appears very attractive when considering that the reaction can take place in water or other media such as water - dimethylisosorbide (DMI) mixtures. 

The polarity of carbohydrates is a prime resource in chemistry. It can be exploited for designing water-soluble substrates which can be used in hydrophobic effect-driven selective reactions or amphiphilic molecules of industrial interest. Though envisioned several decades ago, these strategies find nowadays an immense scope of applications in the context of sustainable chemistry and biobased chemicals, notably in the fields of surfactants and polymers. 

If a fatty acid soap/surfactant is chosen for the biobased grease thickener, there are three components to consider, as shown in fig. 15.2 the hydrophobe, the hydrophile, and the metal cation. The hydrophobe has to make the surfactant compatible with the lubrication fluid. Low-temperature properties are also controlled to a large extent by... 

A new type of biobased material was synthesized from cellulose nano whiskers (CW) and furfuryl alcohol by employing in-situ polymerization method to produce polyfur-furyl alcohol (PFA)/cellulose nanocomposites without the use of solvents or surfactants. Furfuryl alcohol (FA) played a dual role, serving both as an effective dispersant for the cellulose whisker (CW) and as the matrix precursor for the in-situ polymerization. The filler, CW also served multiple functions, by first catalyzing the polymerization of FA, and then acting as an effective matrix modifier, increasing the thermal stability of the consolidated PFA nanocomposite. The polymerization was catalyzed by sulfonic acid residues at the CW surface left over from the whisker preparation [67]. 

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