There has been postulated that sequences conserved in some promoters regions of RhlR and LasR-regulated genes are responsible by these regulation [ 75 ]. Van Hamme, and O. Purified rhamnolipid biosurfactants were applied in the removal of oil from contaminated sandy soil [ 22 ]. The obtained supernatant was stored at room temperature. A one-way analysis of variance ANOVA was used to study the significant difference between mean values, at a significance level of.
The results obtained in this study are in accordance with the data previously reported for other lactobacilli. This class of biosurfactant has been implied in several potential applications such as in bioremediation, food industry, cosmetics and as an antimicrobial agent. Biosurfactants have the potential to replace the use of chemical de-emulsifiers in situ, saving on transport of the oil emulsion and providing a more environmentally-friendly solution. SDS was more effective for aliphatic than aromatic hydrocarbons, whereas biosurfactants removed more aromatics. Biosurfactant yield reached its maximum 2.
From Table 5whatever the substrate used, the yeast strain Candida albicans LV1 was more resistant to the antimicrobial activity of all supernatants.
The possibility of biosurfactant production using cheaper carbon sources was already reported by earlier workers; Mercade et al. An improved strategy to surfactant-enhanced remediation SER is to apply mixture of surfactants at reduced thessis of individual surfactants, which reduces the cost while maintaining the efficiency of remediation [ 17 ]. Bacterial biosurfactants were initially proposed to function as productiin of biodegradable hydrocarbons [ 8 ].
Enhancement of Bacillus subtilis lipopeptide biosurfactants production through optimization of medium composition and adequate control of aeration.
Nature London ; The drop diameters obtained for all the supernatants were significantly higher than those obtained with distilled water. Characterization of the biosurfactant revealed that, it is a lipopeptide with chemical composition of protein According to Henkel et al [ 3 ], use of tyesis substrates in the production processes is likely to increase its influence on the field of microorganism-based production, since they are usually cheaper, maximize the utilization efficiency regarding the overall production process and makes the process more environmentally friendly.
Biosurfactants are organic compounds belonging to various classes including glycolipids, lipopeptides, fatty acids, phospholipids, neutral lipids and lipopolysaccharides [ 1 ]. BSW biosurfactant production using waste motor lubricant oil, BSP biosurfactant production using peanut oil cake, BMW biomass concentration with waste motor lubricant oil, BMP biomass concentration with peanut oil cake.
These yields are very low compared to those obtained in this study with the same strains while using molasses or glycerol as substrate. The antimicrobial activities observed could also be an outcome of the adhesion property of these surface-active agents to the cell surfaces instigating thesus of cell membrane integrity and leading to subsequent collapse of the nutrition cycle [ 56 ].
The strain which showed the lowest surface tension value biowurfactant selected for a further study according to methods described by Bodour and MaierYoussef et al. The results showed that biosurfactants present in the different supernatants caused a significant reduction of surface tensions.
Although biosurfactants have promising use in bioremediation processes, their industrial scale production is currently difficult due to high raw-material costs, high processing costs and low manufacturing output [ 3 ].
Biosurfactant Production by Pseudomonas aeruginosa from Renewable Resources
Surfactants in removal of hydrophobic pollutants Highly hydrophobic contaminants can bind very tightly to soil, therefore inaccessible to biodegradation.
Reuse of waste frying oil for production of rhamnolipids using Pseudomonas aeruginosa Zju. Continuous aeration was provided at the rate 1. Chemically, biosurfactants produced with waste motor lubricant oil and peanut oil cake are similar.
Application of a modified drop-collapse technique for surfactant quantitation giosurfactant screening of biosurfactant-producing microorganisms.
Oil-contaminated soil is especially difficult for bioremediation since oil excess forms droplets or films on soil particles, which is a powerful barrier against microbial degradation [ 41 ]. This clearly indicates the interconnection between produdtion and PQS synthesis.
Also, limiting concentration of multivalent ions such as Mg, Ca, K, Na, and trace element salts increase rhamnolipid yield [ ]. The production in stationary phase is related to factors which contribute to the production in this phase and with other factors that inhibit the production in the exponential phase. Pacheco et al [ ] treated P.
This could be due to the wide variability of biosurfactants metabolism with strain and carbon source used [ 68 ]. To determine the surface activities of the obtained supernatants, drop collapse test and surface tension porduction were carried out. Rhamnolipids are usually precipitated by acidification and extracted using ethyl acetate; extraction of sophorolipids is normally carried out with n-hexane, while for trehalolipids, the preferred solvent is a mixture of chloroform and methanol.
Biosurfactants: Production and Applications
Rhamnolipids have potential microbial activity. Among the isolated bacteria, KSA-T was selected for further studies based on the primary abilities of the selected bacterial strain to hemolytic activity, oil displacement, blue agar test, drop collapse and Emulsion activity. While some Bacillus isolates did not utilize ammonium sulfate for biosurfactant production or microbial growth, however they can utilize sodium nitrate, ammonium nitrate or potassium nitrate Makkar and Cameotra, However, Busscher et al.
This permits reducing Ostwald repining and coalescence which are responsible for an irreversible increase of drops size leading to emulsions prodyction. Correspondence should be addressed to Tene Hippolyte Mouafo ; moc.