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A mixture of the environmentally friendly biosurfactants rhamnolipids and sophorolipids was used as a source of micelles in this study. The Box-Behnken design and response surface methodology was used to investigate the influence of factors on micellar-enhanced ultrafiltration (MEUF). Simulated Cd-containing wastewater was used for testing. Based o...
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... Moreover, the occurrence of secondary contamination is a serious concern, because the surfactant monomers (i.e., non-micellar surfactant molecules) inevitably escape through UF membrane (Castro-Muñoz et al. 2021;Moreno et al. 2022;Xiang et al. 2022). To address this issue, some researchers have employed biosurfactants such as saponins (Samal et al. 2017a;Samal et al. 2017b), rhamnolipids (Verma and Sarkar 2017;Verma and Sarkar 2018), and sophorolipids (Binte Rafiq Era and Mulligan 2023), either alone or in combination (Chai et al. 2019). However, these approaches do not offer a fundamental solution to the problem of surfactant monomer leakage. ...
Micellar-enhanced ultrafiltration (MEUF) technology is an effective method to treat low-concentration heavy metal wastewater. However, the leakage of surfactants in the ultrafiltration (UF) process will inevitably cause secondary pollution. In this study, a biosurfactant of conjugated linoleic acid (CLA) with conjugated double bonds was selected to bind its micelles by simple thermal crosslinking to obtain morphologically stable stearic acid (SA) nanoparticles. The pure SA nanoparticles were obtained by repeated dialysis. The stability of the SA nanoparticles was verified by comparing the particle size distribution and solubility of the materials before and after crosslinking at different pH levels. The effectiveness of SA nanoparticle-enhanced UF in removing heavy metals was verified by exploring the adsorption performance of SA nanoparticles. The dialysis device was used to simplify the UF device, wherein SA nanoparticles were assessed as adsorbents for the elimination of Cu²⁺, Pb²⁺, and Cd²⁺ ions from aqueous solutions under diverse process parameters, including pH, contact time, metal ion concentration, and coexisting ions. The findings indicate that the SA nanoparticles have no evidence of secondary contamination in UF and exhibit compatibility with a broad pH range and coexisting ions. The maximum adsorption capacities for Cu²⁺, Pb²⁺, and Cd²⁺ were determined to be 152.77, 403.56, and 271.46 mg/g, respectively.
... BBD are extensively used for second-order models in absolutesplit-plot experiments,randomized experiments and in robustfactor design settings [46]. It requires three levels for each processing factor, and experimental runs are executed depending on the combination of the factors [47]. ...
Biosurfactants are bio-based amphiphilic molecules with extensive applications in various industries. These eco-friendly alternatives possess numerous advantages over chemical surfactants. However, high production costs hinder market competitiveness of biosurfactants. Production costs of synthetic surfactants range between $1-3/kg, while biosurfactants cost between $20-25/kg. Principal challenges hindering commercialization of biosurfactants are high costs of media constituents and downstream processing, accounting for 30% and 60-80% of production costs, respectively. Thus, cost-effective biosurfactant production would depend on the utilization of environment-friendly low-cost substrates and efficient product recovery. To this end, statistical tools such as Factorial Designs (FD) and Response Surface Methodology (RSM), are employed to optimize the production processes. FD as effective screening models comprise Plackett-Burman Design (PBD) and Taguchi design; and involves quantification of various significant factor effects including the main effect and level of dependency of one factor on the level of one or more factors. RSM predicts appropriate proportions of media constituents and optimal culture conditions; and is reportedly effective in reducing production cost and consequently, market price. Central Composite Design (CCD) and Box-Behnken Design (BBD) are common RSM for optimizing biosurfactants production. CCD assesses the relationship between one factor or more and a set of experimental variables. BBD is considered more proficient than CCD as it requires fewer experimental runs. Most recently, Artificial Neural Network which uses artificial intelligence-based tools to predict biosurfactant production using dependent variables of the process is gaining attention.
... Alternatively, the biosurfactants have low toxicity, high biodegradability and their properties barely change with temperature and salinity [89]. Some promising studies researched high pollutant retention using biosurfactant as saponin [23,35], rhamnolipid [73,89,119], a mixture of rhamnolipids and sophorolipids [120] and a conjugated linoleic acid [72]. A vast gap in literature could be supplied if new MEUF studies use biosurfactants with low CMC. ...
Micellar-enhanced ultrafiltration (MEUF) is a surfactant-based method used to remove low concentrations of contaminants from water and wastewater streams. The process consists of adding surfactant above the critical micelle concentration (CMC) in the contaminated water to solubilize the contaminant in micelles or to retain ionic contaminants via electro-static interaction with ionic micelles. The micelles size should be enough to be retained in a membrane with larger pore size than the one needed for the retention of the contaminant only. This approach allows the increase of the permeate flux. The parameters that influence MEUF, such as surfactant types, membranes, transmembrane pressure, pH, temperature and ionic strength, are summarized in this work. The literature review is focused on the different uses of MEUF in function of the compound to be removed and a comparison of the different methodologies was elaborated. The recent patents linked to MEUF are also presented. A critical analysis of the reviewed data indicated the most frequent gaps in MEUF studies such as the lack of information regarding important parameters including pH, temperature and permeate flux. It was also observed that inaccurate conclusions are commonly associated with imprecise measurements of CMC. The main challenge for future industrial-scale applications of MEUF is to develop studies from the present simple synthetic wastewater in laboratory-scale to industrial wastewater on a MEUF pilot scale. However, this review article shows the versatility of MEUF as a promising method to remove different types of contaminants from water and wastewater streams, and the future challenges to overcome.
... Biosurfactants form part of the reverse micelle extraction of antibiotics and proteins using their surfactant properties [17,179,209] Leather Biodispersan Degreasing: used as skin detergent, emulsifier; tanning and dyeing: wetting and penetration, and promoter [175] Textile Trehaosetetraester Unspecified cHAL2 ...
Surfactants are a broad category of tensio-active biomolecules with multifunctional properties applications in diverse industrial sectors and processes. Surfactants are produced synthetically and biologically. The biologically derived surfactants (biosurfactants) are produced from microorganisms, with Pseudomonas aeruginosa, Bacillus subtilis Candida albicans, and Acinetobacter calcoaceticus as dominant species. Rhamnolipids, sophorolipids, mannosylerithritol lipids, surfactin, and emulsan are well known in terms of their biotechnological applications. Biosurfactants can compete with synthetic surfactants in terms of performance, with established advantages over synthetic ones, including eco-friendliness, biodegradability, low toxicity, and stability over a wide variability of environmental factors. However, at present, synthetic surfactants are a preferred option in different industrial applications because of their availability in commercial quantities, unlike biosurfactants. The usage of synthetic surfactants introduces new species of recalcitrant pollutants into the environment and leads to undesired results when a wrong selection of surfactants is made. Substituting synthetic surfactants with biosurfactants resolves these drawbacks, thus interest has been intensified in biosurfactant applications in a wide range of industries hitherto considered as experimental fields. This review, therefore, intends to offer an overview of diverse applications in which biosurfactants have been found to be useful, with emphases on petroleum biotechnology, environmental remediation, and the agriculture sector. The application of biosurfactants in these settings would lead to industrial growth and environmental sustainability.
... Modification of the rheological characteristics of the food to a desired consistency and texture using emulsification properties [17,179,209] [175] ...
Surfactants are a broad category of tensio-active biomolecules with multifunctional properties applications in diverse industrial sectors and processes. Surfactants are produced synthetically and biologically. The biologically derived surfactants (biosurfactants) are produced from microorganisms with Pseudomonas aeruginosa, Bacillus subtilis Candida albicans and Acinetobacter calcoaceticus as dominant species. Rhamnolipids, sophorolipids, mannosylerithritol lipids, surfactin, and emulsan are well known in terms of their biotechnological applications. Biosurfactants can compete with the synthetic surfactants in terms of performance with established advantages over the synthetic ones including eco-friendliness, biodegradability, low toxicity, and stability over a wide variability of environmental factors. However, at present, the synthetic surfactants are a preferred option in different industrial applications, because of their availability in commercial quantities, unlike the biosurfactants. Usage of synthetic surfactants introduce new species of recalcitrant pollutants to the environment and lead to undesired results where a wrong selection of surfactants is made. Substituting synthetic surfactants with biosurfactants resolves these drawbacks, thus, interest has been intensified in biosurfactant applications in a wide range of industries hitherto considered as experimental fields. This review, therefore, intends to offer an overview of diverse applications where biosurfactants have found useful, with emphases in petroleum biotechnology, environmental remediation and in the agriculture sector. Application of biosurfactant in these settings would lead to industrial growth and environmental sustainability.
Due to the increased use of crude oil and other oil-related products, a large amount of waste is produced and discharged into the environment. These wastes contain toxic heavy metals and petroleum hydrocarbon and lead to further deterioration of the terrestrial and aquatic ecosystems. Their increasing amounts and residual leachates are considered the main obstacle to restoring contaminated environments. Biosurfactants are compounds having high emulsification properties, wetting performance, de-emulsification, detergent formulation, foam formation, and surface activity enhancement to minimize the interfacial tension between liquids, a liquid and a gas or a liquid and a solid. Such features make biosurfactants of high potential applications in diverse industrial set-ups. This field attracts attention from scientists (and policymakers) to develop novel, cost-effective and renewable biosurfactants using molecular engineering and emerging downstream processing. This review comprehensively discusses recent applications of biosurfactants, their preparation, characterization, and potential environmental and other industrial applications. The recent advances in biosurfactants using recombinant DNA technology, mutants and hyper-active microbes were also reviewed. We highlighted the use of sophisticated and highlyaccurate characterization techniques such as high performance-liquid chromatography (HPLC), nuclear magnetic resonance (NMR), thin-layer chromatography (TLC), and gas chromatography-mass spectrometry (GC-MS). Strategies to enhance the efficiency and biosurfactants productivity at a large scale is also discussed.
