Natural roles of biosurfactants

Abstract

Microorganisms produce a variety of surface‐active agents (or surfactants). These can be divided into low‐molecular‐weight molecules that lower surface and interfacial tensions efficiently and high‐molecular‐weight polymers that bind tightly to surfaces. These surfactants, produced by a wide variety of microorganisms, have very different chemical structures and surface properties. It is therefore reasonable to assume that different groups of biosurfactants have different natural roles in the growth of the producing microorganisms. Moreover, as their chemical structures and surface properties are so different, each emulsifier probably provides advantages in a particular ecological niche. Several bioemulsifiers have antibacterial or antifungal activities. Other bioemulsifiers enhance the growth of bacteria on hydrophobic water‐insoluble substrates by increasing their bioavailability, presumably by increasing their surface area, desorbing them from surfaces and increasing their apparent solubility. Bioemulsifiers also play an important role in regulating the attachment–detachment of microorganisms to and from surfaces. In addition, emulsifiers are involved in bacterial pathogenesis, quorum sensing and biofilm formation. Recent experiments indicate that a high‐molecular‐weight bioemulsifier that coats the bacterial surface can be transferred horizontally to other bacteria, thereby changing their surface properties and interactions with the environment.

Produção de biossurfactante por levedura

“…29 Porém algumas espécies podem apresentar pequena produção durante a fase exponencial de crescimento. …”

“…29 Porém algumas espécies podem apresentar pequena produção durante a fase exponencial de crescimento. Exemplos de perfis de produção de bioemulsificante pelas leveduras C. lipolytica IA 1055 30 e Y. lipolyitica IMUFRJ 50682, 18 são apresentados na Figura 1.…”

The emulsifying effect of biosurfactants produced by food spoilage organisms in Nigeria

“…Biosurfactants or microbial surfactants are surface metabolites produced by bacteria, yeast and fungi having very different chemical structures and properties (Ron & Rosenberg, 2001). These biosurfactants are amphiphilic molecules of microbial origin whose hydrophobic and hydrophilic domains depend on the carbon substrate and the organism strain.…”

Screening, stability and antibacterial potential of rhamnolipids from Pseudomonas sp., isolated from hydrocarbon contaminated soil

“…In the past decades, much attention has been intended for biosurfactant owing to their advantages such as biodegra dability, low toxicity, lower critical micelle concentration, environmental compatibility, higher specificity and better activity at extreme conditions like high temperature, high pH and high salinity (Banat, 1995;Cameotra et al, 1998;Ron and Rosenberg, 2001; VanHamme et al, 2006;Singh et al, 2013).…”

“…The surfactin from Bacillus subtilis and rhamnolipid from Pseudomonas has a property of antimicrobial, antiadhesion, antibiofilm and detoxification of oil pollutant (Bechard et al, 1998;Mireles et al, 2001). Another most important application of biosurfactant is bioemlusifier, which stimulates oil production in marginal wells that have approached their economic limit (Banat, 1995;Ron and Rosenberg, 2001). Despite environmental application, biosurfactant have many biomedical application but only a very few work have been reported (Benincasa et al, 2004).…”