In subsequent steps the isolates have to be characterized in order to identify the strains which are interesting for a further investigation. The microplate assay, the penetration assay and the drop collapse assay can be performed in microplates.
They found that the surfactin are able to reduce the surface tension and interfacial tension of water. Plaza et al 36 applied this method and conclude that it is not recommendable due to the large variability they obtained in their results.
Some other microorganisms are able to change the structure of their cell wall which are achieved by them by producing nonionic or lipopolysaccharides surfactants in their cell wall. Therefore, most methods for a general screening of biosurfactant producing strains are based on the physical effects of surfactants.
The mixture is vortexed at high speed for 2 minutes. Biosurfactant free supernatant will turn cloudy but stay red. Chen et al 4 demonstrated the efficiency of the microplate method for high throughput screening purposes.
Therefore, the second aim in screening is the discovery of good production strains with high yields. This is the basic requirement for high throughput screening.
According to Chen et al, 4 a screening method for the isolation of biosurfactant producing microbes must fulfill three requirements: Hydrophobic Interaction Chromatography HIC A method which allows the simultaneous isolation and screening of microbes Thesis on biosurfactants developed by Smyth et al.
Positive strains will cause lysis of the blood cells and exhibit a colorless, transparent ring around the colonies see Fig. Denger K, Schink B. This assay relies on the destabilization of liquid droplets by surfactants. Sampling and isolation of bacteria are the basis for screening of biosurfactant producing microbes.
As enrichment medium, they used mineral media with C and Cn-alkanes and also agar plates with an alkane-soaked filter in the lid. They also found to be enhancing the nutrient transport across membranes and affect in various host-microbe interactions.
It can be measured with an automated tensiometer which is available from many manufacturers. The cells are precipitated by increasing salt concentrations. There are lipopolysaccharides, such as emulsan, produced by Acinetobacter spp. By using these rapid screening methods and by screening many isolates or large culture collections, in the near future various new production strains or new biosurfactants may be found.
Some screening methods can be automated and used for HTS. The three major functions played by biosurfactants including Rosenberg and Ron, A broad application of such methods could eventually lead to the desired upsurge of new commercially interesting strains.
Surface and interface activity: Hydrocarbon-contaminated sites are the most promising for the isolation of biosurfactant producing microbes, but many strains have also been isolated from undisturbed sites. Yakimov and coworkers 17 isolated a biosurfactant producing bacterium of a new genus by using the same enrichment technique.
Thus, a decolorization of the culture shows degradation of hydrocarbons. A positive aggregation reaction shows a clear solution and white aggregates with a diameter of appr.Microbial production of biosurfactants and their importance N.
G. K. Karanth, P. G. Deo and N. K. Veenanadig* Pesticide Residue Abatement Lab, Food Protectants and Infestation Control Department, Central Food Technological Research Institute.
View Biosurfactants Research Papers on ultimedescente.com for free. UNESCO – EOLSS SAMPLE CHAPTERS BIOTECHNOLOGY - Vol. V – Production of Biosurfactants - F.
Siñeriz, R. K. Hommel, H–P. Kleber ©Encyclopedia of Life Support Systems (EOLSS) PRODUCTION OF BIOSURFACTANTS.
This review gives an overview of current methods for the isolation of biosurfactant producing microbes. The common screening methods for biosurfactants are presented. Biosurfactants have shown their potential for remediation of contaminated soil and water. Both organic and inorganic contaminants can be treated through desorption or biodegradation processes.
M.S. thesis. Virginia Polytechnic Institute and State University, Blackburg, VA.
Fava, F. FavaNatural surfactants enhance PCB bioremediation. Biosurfactants-Types, Sources and Applications. The use of biosurfactants for this purpose was found to be an eco-friendly approach and also an alternate to conventional complex remediation systems.
Due to their diversity, biosurfactants are considered as a potential candidate for the environmental cleanup of pollutants. Ph.D. Thesis.Download