Bio-surfactants

Bioavailability is also influenced by certain, albeit poorly understood, characteristics of bacteria. To degrade soil-sorbed molecules, bacteria must either use sorbed molecule directly or facilitate desorption in some manner. Mechanisms underlying the apparent availability of sorbed chemicals are complex due to the divergent properties of chemicals considered, the resultant sorption/desorption mechanisms, the metabolic diversity of microorganisms, and the heterogeneity of soils. Several microbial-based mechanisms have been proposed for the access of soil-sorbed organic chemicals (i) production of bio surfactants (Desai and Banat 1997 Alexander 1999) ... 

At concentrations above their aqueous solubility, the so-called c.m.c., low-molar-mass biosurfactants form micelles in the aqueous phase. Micelles are spherical or lamellar aggregates with a hydrophobic core and a hydrophilic outer surface. They are capable of solubilising nonpolar chemicals in their hydrophobic interior, and can thereby mobilise separate phase (liquid, solid or sorbed) hydrophobic organic compounds. The characteristics for the efficiency of (bio)surfactants are the extent of the reduction of the surface or interfacial tension, the c.m.c. as a measure of the concentration needed to bring about this reduction, and the molar solubilisation ratio MSR, which is the number of moles of a chemical solubilised per mole of surfactant in the form of micelles [96]. 

For the large-scale production of new bio-surfactants [45] and, more recently, of sugar-containing self-assembled organogels with nanostructured morphologies [46]. 

Kiran, S.G., Sabu, A., Selvin, J., 2010. Synthesis of silver nanoparticles by glycolipid bio surfactant produced from marine Brevibacterium casei MSA19. J. Biotechnol. 148, 221-222. 

Anionic surfactants also comprise most of the so-called bio-surfactants. These fulfil important physiological functions in nature. To a lesser degree, they also have commercial applications. 

Banat, I. M., Franzetti, A., Gandolfi, I., Bestett, G., Martinotti, M. G., Fracchia, L., Smyth, T. J., Marchant, R. Microbial bio surfactants production, applications and future potential. Appl Microbiol Biotechnol. 2010, 87, 427-444. 

Desai, J. D., Banat, 1. M. Microbial production of bio surfactants and their commercial potential. Microbiol. Mol. Biol. Rev. 1997, 61, 47-64. 

Makkar, R. S., Rockne, K. J. Comparison of synthetic surfactants and bio surfactants in enhancing biodegradation of polycyclic aromatic hydrocarbons. Environ Toxic Chem. 2003,22(10), 2280-2292. 

Table 10 Major Types of Bio surfactants Produced by Microorganisms... 

---