Use Of Biosurfactants Research Articles

Effects of alkyl polyglycoside (APG) on composting of agricultural wastes

Composting is the biological degradation and transformation of organic materials under controlled conditions to promote aerobic decomposition. To find effective ways to accelerate composting and improve compost quality, numerous methods including additive addition, inoculation of microorganisms, and the use of biosurfactants have been explored. Studies have shown that biosurfactant addition provides more favorable conditions for microorganism growth, thereby accelerating the composting process. However, biosurfactants have limited applications because they are expensive and their use in composting and microbial fertilizers is prohibited. Meanwhile, alkyl polyglycoside (APG) is considered a “green” surfactant. This study aims to determine whether APG addition into a compost reaction vessel during 28-day composting can enhance the organic matter degradation and composting process of dairy manure. Samples were periodically taken from different reactor depths at 0, 3, 5, 7, 14, 21, and 28 days. pH levels, electrical conductivity (EC), ammonium and nitrate nitrogen, seed germination indices, and microbial population were determined. Organic matter and total nitrogen were also measured. Compared with the untreated control, the sample with APG exhibited slightly increased microbial populations, such as bacteria, fungi, and actinomycetes. APG addition increased temperatures without substantially affecting compost pH and EC throughout the process. After 28 days, APG addition increased nitrate nitrogen concentrations, promoted matter degradation, and increased seed germination indices. The results of this study suggest that the addition of APG provides more favorable conditions for microorganism growth, slightly enhancing organic matter decomposition and accelerating the composting process, improving the compost quality to a certain extent.

Characterization and Emulsification Properties of Rhamnolipid and Sophorolipid Biosurfactants and Their Applications

Due to their non-toxic nature, biodegradability and production from renewable resources, research has shown an increasing interest in the use of biosurfactants in a wide variety of applications. This paper reviews the characterization of rhamnolipid and sophorolipid biosurfactants based on their hydrophilicity/hydrophobicity and their ability to form microemulsions with a range of oils without additives. The use of the biosurfactants in applications such as detergency and vegetable oil extraction for biodiesel application is also discussed. Rhamnolipid was found to be a hydrophilic surfactant while sophorolipid was found to be very hydrophobic. Therefore, rhamnolipid and sophorolipid biosurfactants in mixtures showed robust performance in these applications.

Environmental Applications of Biosurfactants: Recent Advances

Increasing public awareness of environmental pollution influences the search and development of technologies that help in clean up of organic and inorganic contaminants such as hydrocarbons and metals. An alternative and eco-friendly method of remediation technology of environments contaminated with these pollutants is the use of biosurfactants and biosurfactant-producing microorganisms. The diversity of biosurfactants makes them an attractive group of compounds for potential use in a wide variety of industrial and biotechnological applications. The purpose of this review is to provide a comprehensive overview of advances in the applications of biosurfactants and biosurfactant-producing microorganisms in hydrocarbon and metal remediation technologies.

Oil Recovery From Fuel Oil Storage Tank Sludge Using Biosurfactants

The petroleum industry generates large amounts of solid and semisolid wastes known as oily sludges. The composition of oily sludge varies due to the large diversity in the quality of crude oils, differences in the processes used for oil–water separation, leakages during industrial processes, and also mixing with the existing oily sludge. Usually, the oily sludge contains water, sand, oils, grease, organic compounds, chemical elements, and metals. Those sludges can be generated in several steps of the petroleum production and refining, such as in oil/water separation steps and in the bottom of tanks. The accumulation of oily residues in petroleum industry poses a serious environmental problem. The purpose of this work was evaluate an alternative process to removal of oily sludges through the use of biosurfactants to reduce the viscosity and promote formation of oil/water emulsions making sludge pumping easier and permitting crude oil recovery after breaking the emulsion. Five bacterial isolates were selected for their biosurfactant production potential after screening microorganisms recovered from oil-contaminated sites. Supernatants obtained from autoclave cell suspensions (hereby referred to as autoclaved-supernatant) were mixed with oily sludge collected from fuel oil storage tanks to a final concentration of 0.01%, in order to separate the oil from the inert material. The process proved to be highly efficient for oil recovery, and resulted in up to 95% reduction in sludge volume. The use of cell-free supernatant medium obtained from biosurfactant-producing bacterial strains to treat oily sludges may be an economically and environmentally viable technology, considering the small volume of microbial culture required for the treatment.

Rhamnolipid and surfactin inhibit Listeria monocytogenes adhesion

The aim of this study was to assess the potential use of biosurfactants in inhibiting the Listeria monocytogenes strains adhesion to polystyrene surfaces. Surfactin and rhamnolipids were used. The adhesion profiles of 15 strains showed that most of these bacteria can be classified as moderate to strongly adherent. Both biosurfactants were able to reduce bacterial adhesion, and the effect was more pronounced against the strongly adherent strains. The most promising result was obtained for ATCC7644 strain, which showed an adhesion reduction of 84% for surfactin (30-h growth period). Rhamnolipids decreased the ATCC15313 adhesion by 82%. ATCC19112 adhesion was reduced by 53% for surfactin and purified rhamnolipid. Sodium dodecyl-sulphate was less effective than the biosurfactants, showing maximal adhesion reduction of 23% for 19112 and 7644. The purified rhamnolipid inhibited 100% of the growth of strongly adherent, suggesting that this surfactant can be exploited as a potential agent to control L. monocytogenes.

Electrokinetic remediation of gasoil contaminated soil enhanced by rhamnolipid

Electrokinetic remediation (EKR) has been investigated as one of the best technologies in soil remediation but its applications for organic contaminants have been limited due to low solubility of organics in water and their non-ionic nature. The use of biosurfactants may increase the remediation efficiency by increasing the solubility of organics. The purpose of the introduction of complexing substances is to enhance the EKR process forming complexes and/or increasing the electro-osmotic flow. In this study, the removal of gasoil from a soil using electrokinetic method was investigated in the presence of Rhamnolipid at various concentrations. EKR experiments were undertaken on a gasoil contaminated soil (20,000 ppm). Graphite carbon electrodes were used to provide an electrical direct current (ddp 30–60 V). Results showed that increasing the dose of Rhamnolipid, the efficiency of gasoil removal increased up to 86.7%. Moreover, the lower concentration of the gasoil observed in the liquid phase at the higher concentration of the biosurfactant clearly indicated that the Rhamnolipid addition can enhance gasoil biodegradation.

New Technologies for Toxic Metals Removal from Contaminated Sites

The pollution of soils by toxic metals like lead, arsenic, chromium, copper, nickel and zinc has significant economic, environmental and social impacts in industrialized countries. In the last decade, different physical, chemical, biological and electrochemical technologies have been developed to solve this problem. The physical separation technologies for metal-polluted soil remediation are mainly screening, hydrodynamic classification, gravity concentration, froth flotation, magnetic separation, electrostatic separation, and attrition scrubbing. The chemical soil treatments use different extractants like acids or bases, surfactants, salts and redox agents to extract metallic pollutants from soils. The metal-polluted soils can also be rehabilitated using biological means like phytoextraction techniques, the use of biosurfactants and bioleaching processes. Finally, much research has been undertaken in recent years concerning the application of electrotechnologies for soil decontamination, including electrokinetic and chelator-enhanced electrokinetic extraction techniques. This paper covers recent developments in the field of technological options to remove toxic metals from polluted sites based on 16 patents analyzed. Keywords: Soil, metal, leaching, electrokinetic, phytoremediation, phytoextraction, surfactant, biosurfactant, flotation, solvent

English

Industrial waste and sewage pollute more than 2/3 of India's water resources. Stream pollution is a serious and growing problem in most developing countries where there is little waste water treatment. Increasing contamination of aquatic resources with pollution including heavy metals (like chromium, lead, cadmium, zinc, nickel etc.) endangers aquatic biota and declines water quality. Bioremediation is a process that uses microorganisms or their enzymes to return the environment altered by contaminants to its original condition. Biological methods for the removal of heavy metals from industrial waste may provide an attractive alternative to the physico-chemical process; biosurfactants are one of the compounds that aid in alleviating the heavy metals. Microorganisms while trying to utilize substrates like hydrocarbon as carbon source facilitate the diffusion into cell by producing a variety of substances called biosurfactants. Several microbes such as Bacillus sp., Pseudomonas sp., Acinetiobacter sp. and Arthobacter sp. are reported to produce biosufactants. Compared to synthetic compounds, biosurfactants offer the advantages of little or no environmental impact and the possibility of in situ production. Studies in recent past have demonstrated the successful use of biosurfactants for facilitating the degradation of organic pollutants in soil and water. In the light of above the present study is aimed to carry out the assessment of efficiency of biosurfactants (Rhamnolipid) producing microorganisms (Pseudomonas sp .) isolated from heavy metal contaminated site. Keywords - Bioremediation, Biosurfactants, Pseudomonas, Bacillus, Acinetiobacter , Arthobacter, Rhamnolipid, Heavy metals

Suppression of disease in tomato infected by Pythium ultimum with a biosurfactant produced by Pseudomonas koreensis

The use of biosurfactants is a promising alternative in biological control of zoospore-producing oomycetes, which are a major plant pathogen world-wide in a wide variety of crops. Oomycetes are of particular concern in closed hydroponic cultivation systems. The present study investigated the efficacy of a biosurfactant produced by Pseudomonas koreensis and added as a crude extract against the oomycete Pythium ultimum in hydroponic tomato cultivation. A significant reduction in disease was observed. Biosurfactant addition did not affect the indigenous root microflora when evaluated as sole carbon source utilisation. Chemical analysis, using electrospray hybrid mass spectrometry (ESI-MSMS), of the biosurfactant indicated it to be lokisin, a cyclic lipopeptide. These results confirm that biosurfactants are important in developing sustainable biological control strategies for oomycetes.

Enhanced bioremediation of crude oil utilizing lipophilic fertilizers combined with biosurfactants and molasses

Many research studies have demonstrated the feasibility and efficacy of fertilization with nitrogen and phosphorus to combat oil spills in marine environments. Rapid dilution of water-soluble nutrients can be overcome by oleophilic formulations that retain optimal nutrient concentrations at the oil–water interface where biodegradation occurs. Previous work has demonstrated that biodegradation processes are enhanced by the addition of lipophilic fertilizers of natural origin (uric acid and lecithin). In this work, we examined the effectiveness of these nutrients in combination with biosurfactants (rhamnolipids) and molasses (source of C and vitamins) to enhance the biodegradation by naturally occurring microorganisms. It was found that the use of biosurfactants resulted in an increased removal of petroleum hydrocarbons (96% removal of C19–C34 n-alkanes within a period of 18 days) as well as in a reduction of the lag phase (almost 80% removal was achieved within the first week of biosurfactant application).

Characterization of biosurfactant-producing strains of fluorescent pseudomonads in a soilless cultivation system

The use of biosurfactants is a promising alternative in biological control of zoospore-producing plant pathogens. In the present study, biosurfactant production by the indigenous population of fluorescent pseudomonads in a soilless plant cultivation system was studied during the growing season. A total of 600 strains was screened and of these 18.5% were observed to produce biosurfactants. Production of both antibiotics and biosurfactant was uncommon among the isolated strains. A selective effect of the cultivation system filter was observed on the biosurfactant-producing strains and these strains were only occasionally observed after the filter, despite having a significantly higher motility than the nonbiosurfactant-producing strains. The majority of biosurfactant-producing strains were isolated from the filter skin, which suggests that this is a suitable surface for inoculation with biocontrol strains.

Use of biosurfactants from urban wastes compost in textile dyeing and soil remediation

A compost isolated humic acid-like (cHAL) material was pointed out in previous work for its potential as auxiliary in chemical technology. Its potential is based on its relatively low 0.4gL(-1) critical micellar concentration (cmc) in water, which enables cHAL to enhance the water solubility of hydrophobic substances, like phenanthrene, when used at higher concentrations than 0.4gL(-1). This material could be obtained from a 1:1 v/v mixture of municipal solid and lignocellulosic wastes composted for 15 days. The compost, containing 69.3% volatile solids, 39.6% total organic C and 21C/N ratio, was extracted for 24h at 65 degrees C under N2 with aqueous 0.1molL(-1) NaOH and 0.1molL(-1) Na4P2O7, and the solution was acidified to separate the precipitated cHAL in 12% yield from soluble carbohydrates and other humic and non-humic substances. In this work two typical applications of surfactants, i.e., textile dyeing (TD) and soil remediation by washing (SW), were chosen as grounds for testing the performance of the cHAL biosurfactant against the one of sodium dodecylsulfate (SDS), which is a well established commercial synthetic surfactant. The TD trials were carried out with nylon 6 microfiber and a water insoluble dye, while the SW tests were performed with two soils contaminated by polycyclic aromatic hydrocarbons (PAH) for several decades. Performances were rated in the TD experiments based on the fabric colour intensity (DeltaE) and uniformity (sigmaDeltaE), and in the SW experiments based on the total hydrocarbons concentration (CWPAH) and on the residual surfactant (Cre) concentrations in the washing solution equilibrated with the contaminated soils. The results show that both cHAL and SDS exhibit enhanced performance when applied above their cmc values. However, while in the TD case a significant performance effect was observed at the surfactants cmc value, in the SW case the required surfactants concentration values were equivalent to 25-125xcmc for cHAL and to 4-22xcmc for SDS. The vis-a-vis comparison of the two surfactants gave the following results: in the TD case the cHAL biosurfactant at 0.4gL(-1) yields good colour intensity and equal colour uniformity as SDS at 5gL(-1), in the SW case cHAL was found to enhance CWPAH by a factor of 2-4 relative to SDS with one soil, whereas with the other soil the two surfactants behaved similarly. The Cre data, however, showed that both soils absorbed by far more SDS (68-95%) than cHAL (12-54%). The results point out intriguing technological and environmental perspectives deriving from the use of compost isolated biosurfactants in the place of synthetic surfactants.

Combination of natural gums and synthetic surfactants for washing of a soil highly contaminated with crude

Surfactant-enhanced washing has become a very important option for the remediation of soils contaminated with a variety of compounds and elements, i.e., petroleum hydrocarbons, pesticides, dense nonaqueous-phase liquids, metals, and others. The use of biosurfactants has merged as an interesting solution. Many authors have published the use of soil-washing processes by means of biosurfactants produced by different bacteria to clean soils contaminated mainly with petroleum hydrocarbons, metals, and pesticides. The use of natural products produced by plants has been less explored. There are two basic aims of this study: first, to compare the performance of two natural gums (guar and locust bean gum [LBG]) with a synthetic surfactant sodium dodecyl sulfate (SDS), in terms of their total petroleum hydrocarbon (TPH) removal capabilities; second, to evaluate the behavior of these natural products (guar and LBG) combined separately with two synthetic surfactants (SDS or polyethoxylated sorbitan monooleate [TW80]), with respect to both TPH removal and removal efficiencies. When a soil highly contaminated with Mexican crude (about 98,000 mg/kg) was cleaned with guar and LBG, TPH removal values as high as 49.6 and 47.7% were obtained, using gums at concentrations of 0.5%, in comparison with 36.3% of TPH removal, reached by SDS at the same surfactant concentration. Importantly, note that the soil contained TPH-diesel; TPH-gasoline and heavier fractions including benzene, toluene, ethyl benzene and xylene, polyaromatic hydrocarbons; and metals, including high amounts of calcium and magnesium.

Oil removal from used sorbents using a biosurfactant

Oil spills impose serious damage on the environment. Mechanical recovery by the help of oil sorbents is one of the most important countermeasures in oil spill response. Most sorbents, however, end up in landfills or in incineration after a single use. These options either produce another source of pollution or increase the oil recovery cost. In this study a biosurfactant was used to clean used oil sorbents. This use of biosurfactants is new. Washing parameters tested included sorbent type, washing time, surfactant dosage and temperature. It was found that with biosurfactant washing more than 95% removal of the oil from sorbents was achieved, depending on the washing conditions. Biosurfactants were found to have considerable potential for recycling the used sorbents.

A biosurfactant-enhanced soil flushing for the removal of phenanthrene and diesel in sand.

In order to examine the potential of biosurfactants in soil remediation, and to investigate the effects of several operating conditions, such as flow rate, biosurfactant concentration and surfactant type, biosurfactant-enhanced soil flushing was conducted. In the biosurfactant-enhanced soil flushing process, the removal efficiency increased as the flow rate decreased. Rhamnolipid showed no effect on the removal efficiency of phenanthrene and diesel from sand in the concentration range 0.3-0.5%. However, rhamnolipid showed higher efficiencies for the removal of phenanthrene and diesel from sand than Tween 80. Based on total recovery, following an equivalent pore volume flush, it was more difficult to remove diesel than phenanthrene. In order to obtain the specific removal efficiency, more pore volumes of surfactant solution may be required in field applications. Under optimum conditions, the biosurfactant removed as much as 70% of the phenanthrene and 60% of the diesel in the sand. These results indicate that the use of biosurfactants in the flushing process is favorable, not only with respect to the environment, but also on removal efficiencies.

The use of biosurfactants in flotation: application for the removal of metal ions

The removal of zinc and chromium ions from aqueous solutions was investigated in the present study by the application of a two-stage separation process, termed sorptive flotation. The first stage consists of the metal ions sorption onto an appropriate sorbent material, followed by successive flotation as the second stage. The sorbent material was either laboratory prepared goethite, or in situ generated ferric hydroxide. The biologically produced surface active agents Surfactin-105 and Lichenysin-A, were applied as flotation collectors for the separation of the metal-loaded sorbents. The main studied parameters were the concentrations of sorbent materials, as well as of biosurfactants. Under the application of optimised conditions better floatabilities of metal-laden sorbents were obtained, when using the biosurfactants in comparison with the application of conventional (chemically produced) surfactants (sodium dodecyl sulphate or dodecylamine) examined under similar conditions.

Biosurfactant- and biodegradation-enhanced partitioning of polycyclic aromatic hydrocarbons from nonaqueous-phase liquids.

A study was conducted on the effect of two different biological factors, microbial surfactants and biodegradation, on the kinetics of partitioning of polycyclic aromatic hydrocarbons (PAHs) from nonaqueous-phase liquids (NAPLs). The effect of rhamnolipid biosurfactants on partitioning into the aqueous phase of naphthalene, fluorene, phenanthrene, and pyrene, initially dissolved in di-2-ethylhexyl phthalate (DEHP) or 2,2,4,4,6,8,8-heptamethylnonane (HMN), was determined in multiple-solute experiments. Biosurfactants at a concentration above the CMC enhanced the partitioning rate of fluorene, phenanthrene, and pyrene but were ineffective with naphthalene. Enhancement of partitioning was also observed in the presence of suspended humic acid-clay complexes, which simulated the solids often present in the subsurface. Biosurfactants sorbed to the complexes modified PAH partitioning between the NAPL and these solids, increasing the fraction of solid-phase PAH. Biodegradation-driven partitioning was estimated in mineralization experiments with phenanthrene initially present in HMN and three representative soil bacterial strains, differing in their potential adherence to the NAPL. In the three cases, the rates of mineralization were very similar and significantly higher than the abiotic rate of partitioning. Our study suggests that in NAPL-polluted sites, partitioning of PAH may be efficiently enhanced by in situ treatments involving the use of biosurfactants and biodegradation.

Comparative Evaluation of Aerobic and Anaerobic Treatment of High Oil and Grease Rendering Wastewater

Comparative Evaluation of Aerobic and Anaerobic Treatment of High Oil and Grease Rendering WastewaterThis study evaluated and compared the performance of a conventional activated sludge system to a batch anaerobic digestion system dealing with high oil and grease (O& 50,000-66,000 mg/L) wastewater with COD and BOD levels as high as 100,000 mg/L and 80,000 mg/L respectively. The use of biosurfactants for treatment was also examined. Batch laboratory experimental results and pilot-scale data...Author(s)Lei LiuG. NakhlaA. BassiMustafa Al-SabawiSourceProceedings of the Water Environment FederationSubjectSession 22 Industrial Issues and Treatment Technology: Food Processing WastewatersDocument typeConference PaperPublisherWater Environment FederationPrint publication date Jan, 2003ISSN1938-6478SICI1938-6478(20030101)2003:10L.157;1-DOI10.2175/193864703784679134Volume / Issue2003 / 10Content sourceWEFTECFirst / last page(s)157 - 169Copyright2003Word count192

Surfactant-enhanced remediation of contaminated soil: a review

Extracting aqueous solutions with or without additives are employed to solubilize contaminants in soil. Since water solubility is the controlling removing mechanism, additives are used to enhance efficiencies. These additives can reduce the time to treat a site compared to the use of water alone. Additives must be of low toxicity and biodegradable. The research in this area has focussed mainly on halogenated volatile organic compounds (VOCs) and is still quite limited for metal removal. Additives include surfactants, organic and inorganic acids, sodium hydroxide, which can dissolve organic soil matter, water-soluble solvents such as methanol, displacement of cations with nontoxic ones, complexing agents such as EDTA, acids in combination with complexing agents or oxidizing/reducing agents. Cationic, anionic and nonionic surfactants are particularly used for soil washing or flushing. They contain both hydrophobic and hydrophilic portions, making them ideal for solubilization of hydrophobic compounds. Numerous studies have indicated that surfactants enhance recoveries of non-aqueous phase liquids (NAPLs). There have also been indications that pretreatment of soil with surfactant washing to solubilize hydrophobic compounds such as PAHs enhances biodegradation of these contaminants. A few in situ field studies have been performed with surfactants. Large-scale treatment has been done mostly for organic removal. Soil pH, soil type, cation exchange capacity (CEC), particle size, permeabilities and contaminants all affect removal efficiencies. High clay and organic matter contents are particularly detrimental. Understanding the chemistry of the binding of the contaminant and the hydrogeology of the site are very important. Once the water is pumped from the soil, it must be extracted and then treated to remove the hydrocarbons and metals. Several technologies exist such as sodium hydroxide or sodium sulfide precipitation, ion exchange, activated carbon adsorption, ultrafiltration, reverse osmosis, electrodialysis and biological processes. Recycling of the surfactants is desired to decrease treatment costs. This paper will provide an overview of the laboratory research, field demonstration and full-scale application of surfactants for the remediation of contaminated soil. The majority of pilot scale in situ flushing tests, particularly in the United States, have involved the use of surfactants and co-solvents. There are only a few full-scale projects however. Recent laboratory scale efforts by the authors concerning the use of biosurfactants, biologically produced surfactants, to enhance the removal of copper, cadmium and zinc from contaminated soils and sediments are discussed. Three types of biosurfactants were evaluated for their effectiveness. They included a lipopeptide called surfactin from Bacillus subtilis, a rhamnolipid from Pseudomonas aeruginosa and a sophorolipid from Torulopsis bombicola. The results indicated the feasibility of removing the metals with the anionic biosurfactants even though the exchangeable fractions were not significant.

Rhamnolipid-induced removal of lipopolysaccharide from Pseudomonas aeruginosa: effect on cell surface properties and interaction with hydrophobic substrates.

Little is known about the interaction of biosurfactants with bacterial cells. Recent work in the area of biodegradation suggests that there are two mechanisms by which biosurfactants enhance the biodegradation of slightly soluble organic compounds. First, biosurfactants can solubilize hydrophobic compounds within micelle structures, effectively increasing the apparent aqueous solubility of the organic compound and its availability for uptake by a cell. Second, biosurfactants can cause the cell surface to become more hydrophobic, thereby increasing the association of the cell with the slightly soluble substrate. Since the second mechanism requires very low levels of added biosurfactant, it is the more intriguing of the two mechanisms from the perspective of enhancing the biodegradation process. This is because, in practical terms, addition of low levels of biosurfactants will be more cost-effective for bioremediation. To successfully optimize the use of biosurfactants in the bioremediation process, their effect on cell surfaces must be understood. We report here that rhamnolipid biosurfactant causes the cell surface of Pseudomonas spp. to become hydrophobic through release of lipopolysaccharide (LPS). In this study, two Pseudomonas aeruginosa strains were grown on glucose and hexadecane to investigate the chemical and structural changes that occur in the presence of a rhamnolipid biosurfactant. Results showed that rhamnolipids caused an overall loss in cellular fatty acid content. Loss of fatty acids was due to release of LPS from the outer membrane, as demonstrated by 2-keto-3-deoxyoctonic acid and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis and further confirmed by scanning electron microscopy. The amount of LPS loss was found to be dependent on rhamnolipid concentration, but significant loss occurred even at concentrations less than the critical micelle concentration. We conclude that rhamnolipid-induced LPS release is the probable mechanism of enhanced cell surface hydrophobicity.