This paper reviews the literature on various biosurfactant mixtures used to obtain foams. The interactions between different biosurfactants, biosurfactants, and synthetic surfactants, biosurfactants' ...interactions with various additives (as non-surface-active macromolecules or particles), and the impact of pH and ionic strength variations on adsorption processes, foamability, foam stability, and rheology are discussed. Biosurfactants are natural and synthetic compounds that can facilitate the process of foam formation and stabilisation; they are an alternative to classical surfactants. Research on such materials will allow the development of innovative foaming technologies that minimise the negative environmental effects of foaming compounds without losing the properties of the final product.
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Biosurfactants are economically most sought after biotechnological compounds of the 21st century. However, inefficient bioprocessing has mitigated the economical commercial production of these ...compounds. Although much work is being done on the use of low‐cost substrates for their production, a paucity of literature exists on the upcoming bioprocess optimization strategies and their successes and potential for economical biosurfactant production. This review discusses some of the latest developments and most promising strategies to enhance and economize the biosurfactant production process. Recent market analysis, developments in the field of optimally formulated cost credit substrates for enhanced product formation and subsequent process economization are few of the critical aspects highlighted here. Use of nanoparticles and coproduction of biosurfactant along with other commercially important compounds like enzymes, are other upcoming bioprocess intensification strategies. The recent developments discussed here would not only give an overview of pertinent parameters for economic biosurfactant production but would also bring to fore multiple strategies that would open up new avenues of research on biosurfactant production. This would go a long way in making biosurfactants a commercially successful compound of the current century.
Currently, the bioremediation of petroleum hydrocarbons employs microbial biosurfactants because of their public acceptability, biological safety, and low cost. These organisms can degrade or ...detoxify organic-contaminated areas, such as marine ecosystems. The current study aimed to test the oil-biodegradation ability of the fungus Drechslera spicifera, which was isolated from contaminated soil samples in Riyadh, Saudi Arabia. We used hydrocarbon tolerance, scanning electron microscopy, DCPIP, drop-collapse, emulsification activity, recovery of biosurfactants, and germination assays to assess the biodegradation characteristics of the D. spicifera against kerosene, crude, diesel, used, and mixed oils. The results of DCPIP show that the highest oxidation (0.736 a.u.) was induced by crude oil on the 15th day. In contrast, kerosene and used oil had the highest measurements in emulsification activity and drop-collapse assays, respectively. Meanwhile, crude and used oils produced the highest amounts of biosurfactants through acid precipitation and solvent extraction assays. Furthermore, the biosurfactants stimulated the germination of tomato seeds by more than 50% compared to the control. These findings highlight the biodegradation ability of D. spicifera, which has been proven in the use of petroleum oils as the sole source of carbon. That might encourage further research to demonstrate its application in the cleaning of large, contaminated areas.
Globally, the rapid increase in the human population has given rise to a variety of industries, which have produced a variety of wastes. Due to their detrimental effects on both human and ...environmental health, pollutants from industry have taken centre stage among the various types of waste produced. The amount of waste produced has therefore increased the demand for effective waste management. In order to create valuable chemicals for sustainable waste management, trash must be viewed as valuable addition. One of the most environmentally beneficial and sustainable choices is to use garbage to make biosurfactants. The utilization of waste in the production of biosurfactant provides lower processing costs, higher availability of feedstock and environmental friendly product along with its characteristics. The current review focuses on the use of industrial wastes in the creation of sustainable biosurfactants and discusses how biosurfactants are categorized. Waste generation in the fruit industry, agro-based industries, as well as sugar-industry and dairy-based industries is documented. Each waste and wastewater are listed along with its benefits and drawbacks. This review places a strong emphasis on waste management, which has important implications for the bioeconomy. It also offers the most recent scientific literature on industrial waste, including information on the role of renewable feedstock for the production of biosurfactants, as well as the difficulties and unmet research needs in this area.
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•Microbial biosurfactant production from wastes and wastewaters is sustainable process.•Biosurfactants are less toxic and biodegradable than chemical-based surfactants.•Wastes from food and agro industries were well studied to produce biosurfactants.•Biosurfactant classification and selection criteria were documented.
Heavy metal toxicity has become a pressing ecological problem that affects the ecosystems through bioaccumulation, representing a serious public health hazard. Many conventional strategies have been ...developed and applied to decontaminate and restore metal-contaminated areas. However, these conventional approaches are not very suitable and environmentally safe for heavy metal remediation because of their high operational costs, high energy requirements, post-waste disposal problems, and secondary pollutant generation. Thus, biosurfactant-based bioremediation of heavy metals is a sustainable and promising approach because of its biodegradation capability, economic effectiveness, and ecofriendly nature. Pseudomonas sp., Bacillus sp., Citrobacter freundii, and Candida tropicalis have been isolated as potential sources of biosurfactants and produce compounds such as surfactin, rhamnolipids, and sophorolipids. Owing to the severity of heavy metal pollution in certain parts of the environment, biosurfactants have garnered great interest and attention as an emerging multi-functional technology of the new century for successful removal of heavy metal pollutants. The present study describes the role of biosurfactants in the bioremediation of heavy metals from contaminated environments. Moreover, the interaction mechanism underlying biosurfactant–metal complexation and metal remediation are discussed. Based on the review of the literature, further research is warranted to elucidate the mechanistic roles and explore the structural characterization and gene regulation of biosurfactants to improve their productivity and expand their applicability in bioremediation.
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•Soil contamination with toxic heavy metals is a serious global concern.•Biosurfactant-based bioremediation of heavy metals is a promising approach.•Here, the interaction between biosurfactants and heavy metals is described.•The mechanism through which biosurfactants remove soil heavy metals is elucidated.•Biosurfactant-enhanced soil recovery and remediation methods are discussed.
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•Stable crude oil/water nanoemulsions stabilized by biosurfactant are formulated.•The formulated nanoemulsions possess favorable characteristics for EOR applications.•At low shear ...rates, the emulsions showed shearing-thinning behavior.•At high shear rates, the emulsions showed shearing-thickening behavior,•Crude oil is completely recovered from the emulsion in < 1 h upon HCl addition.
The successful utilization of nanoemulsions in several applications would require the formulation of emulsions with excellent characteristics. Ideally, the nanoemulsions should be stabilized using bioemulsifiers, which do not negatively impact the environment throughout their cradle-to-grave lifetime. Thus, crude oil-in-water (O/W) nanoemulsions with exceptional properties were prepared in this study using rhamnolipid biosurfactant as a bioemulsifier. The obtained results reveal that rhamnolipid can produce O/W nanoemulsions with an average droplet size as low as 35.0 ± 6.6 nm. The nanoemulsions also have highly negative zeta potential, low interfacial tension, and long-term kinetic stability. Interestingly, almost all the formulated O/W nanoemulsions using different rhamnolipid dosages and oil/water ratios showed three different flow behaviors (i.e., shear-thinning, Newtonian, and shear-thickening at low, medium, and high shear rates, respectively). Additionally, the nanoemulsion formulated using 50/50 crude oil/water volumetric ratio displayed higher apparent viscosity than the crude oil at elevated temperatures (greater than 63 ⁰C). Furthermore, despite that all the formulated nanoemulsions were extremely stable, they can be easily, completely, and quickly (within ≤ 1 h) switched-off if needed via pH-switching. The results presented herein demonstrate the potential of biosurfactants for enhanced oil recovery (EOR) and other oilfield applications.
This paper reviews the literature on various natural and synthetic biosurfactants, which can facilitate the process of foam formation and stabilisation. Biosurfactants are an alternative to classical ...surfactants. For example, proteins, through their stabilising properties, can be used both in the food industry and in cosmetics, and this confirms their versatile properties and application in many areas of industry. Sugar-based foaming agents, on the other hand, are characterised by their ability to maintain high foam stability, and their natural origin and biodegradability are attractive substitutes for classical compounds of this type. This review aims to compare the effects of various compounds on the properties and stability of foams. Research on such materials will allow the development of innovative foaming technologies that minimise the negative environmental impacts of foaming compounds without losing the properties of the final product.
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•Residues of vine-trimming shoots can be used as carbon sources for BS production.•The halotolerant ZSB10 strain produced BS using hydrolyzed vine-trimming shoots.•BS production was enhanced when MSM ...medium was added to HC and CH hydrolyzates.•A higher yield of extracellular BS than cell-bond BS was obtained by B. tequilensis.•Extracellular BS had better surfactant and emulsifying properties than cell-bond BS.
The strain Bacillus tequilensis ZSB10, isolated from Mexican brines, was able to grow and produce extracellular and cell-bound biosurfactants using nine culture broths formulated from hydrolyzates obtained from the cellulosic and hemicellulosic fractions of vine-trimming wastes. The results confirm its halotolerance since it managed to grow both in the presence and absence of salts. It also was able to consume sugars such as glucose and xylose. The process was then scaled up into a 2-L bioreactor using the mixture of hemicellulosic (50%) and cellulosic hydrolyzate (50%) supplemented with mineral salt medium as culture medium at different biomass concentrations. Crude extracellular biosurfactant yielded 1.52g/L and lowered the surface tension to 38.6mN/m with a critical micelle concentration of 177.14mg/L. Furthermore, it was able to emulsify with kerosene after 24h (E24=47%). Crude cell-bound biosurfactant only yielded 0.0783g/L and showed lower emulsifying characteristics than extracellular biosurfactant (E24=41% with kerosene).
Nowadays, the worldwide search regarding renewable products from natural resources is increasing due to the toxicity of chemical counterparts. Biosurfactants are surface-active compounds that contain ...several physiological functions that are used in industries like food, pharmaceutical, petroleum and agriculture. Microbial lipopeptides have gained more attention among the researchers for their low toxicity, efficient action and good biodegradability when compared with other surfactants. Because of their versatile properties, lipopeptide compounds are utilized in the remediation of organic and inorganic pollutants. This review presented a depth evaluation of lipopeptide surfactants in the bioremediation process and their properties to maintain a sustainable environment. Lipopeptide can acts as a replacement to chemical surfactants only if they meet industrial-scale production and low-cost substrates. This review also demonstrated the production of a lipopeptide biosurfactant from a low-cost substrate and depicted plausible techniques to manage the substrate residues to determine its ability in the different applications particularly in the bioremediation process.
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•The different types of lipopeptides were described based on their structure and isoforms containing amino acids.•The substrates and microbes explained in this study exhibited a better yield of lipopeptide biosurfactants.•The lipopeptide would overcome the downsides of chemical surfactants in environmental applications.•Lipopeptide surfactant is one of the best eco-friendly techniques to remediate industrial pollutants.
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