Polymeric biosurfactants

Some enzymatically prepared glycolipids and polymeric biosurfactants, such as trehalolipids and emulsan [31b, 526], as well as acylated proteins (see Section 5) are mainly of nonoinic nature. 

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. 

In contrary to the other surface active molecules, polymeric biosurfactants are high-molecular weight compounds and generally exhibit high emulsifying activity. Among current polymeric biosurfactants, a more potent one is emulsan. 

Polymeric biosurfactants have begun to receive attention because of their renewable source and potential natural compatibility for use in medical and pharmaceutical applications. They may be produced and extracted from a number of microbiological sources and have indicated great potential utility in specific applications. Since they are generally produced as products of fermentation processes, their cost, for now, at least, may preclude their wide application in general industrial or commercial products. It has also been found that the exact structure of the amphiphilic material produced and the overall yield of useful product can be highly... 

Because blood is a multicomponeiit system containing a large number of ionized and molecular species differing in size, mass, cell structure, and coUoidal particles, several processes such as polymerization of blood proteins, reaction with biosurfactants, and other accompanying processes besides adsorption can take place on the surface of adsorbent carbon. These processes can influence the adsorptive removal of toxics and other harmful components from blood during hemoperfusion. Furthermore, experiments concerning destraction of thrombocytes and deposition of platelets and leucocytes on the adsorbent carbon surface can only be carried out on animal blood. 

Yeast and bacteria can produce biosurfactants, biological surfactants from various substrates including sugars, oils, alkanes and wastes [5]. Some types of biosurfactants are glycolipids, lipopeptides, phospholipids, fatty acids, neutral lipids, polymeric and particulate compounds [6]. Most are either anionic or neutral, while only a few with amine groups are cationic. The hydrophobic part of the molecule is based on long-chain fatty acids, hydroxy fatty acids or a-alkyl-jS-hydroxy fatty acids. The hydrophilic portion can be a carbohydrate, amino acid, cyclic peptide, phosphate, carboxylic acid or alcohol. 

Well-defined sophorolipid biosurfactant analogs were also prepared via enzymatic synthesis for the evaluation of the bioactivity and as building blocks for the preparation of glycolipid-based polymers [107]. The direct enzymatic ring-opening polymerization of lactone sophorolipids (SLs) was carried out with lipases. The reaction proceeded with the formation of mono-acylated lactone SLs and the subsequent conversion of the intermediates to oligomers and polymers (Scheme 12) [108]. 

Satpute SK, Banat IM, Dhakephalkar PK, Banpurkar AG, Chopade BA (2010) Biosurfactants, bioemulsifiers and exopolysaccharides from marine microorganisms. Biotechnol Adv 28 436-450 Sheng GP, Yu HQ, Yue ZB (2005) Production of extracellular polymeric substances from Rhodopseudomonas acidophila, in the presence of toxic substances. Appl Microbiol Biotechnol 69 216-222 Singh R, Paul D, Jain RK (2006) Biofilms implications in bioremediation. Trends Microbiol 14 389-397... 

Keywords Atom transfer radical polymerization, biomaterials, biosurfactants, plasma treatment, polymer brushes, polydimethylsiloxane, silicone rubber, surface modification, voice prostheses... 

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