Synthetic Surfactants Research Articles

Development of a ‘green’ nanoformulation of neem oil-based nanoemulsion for controlling mosquitoes in the sustainable ecosystem

Controlling vector borne disease insects control such as mosquitoes and reducing the use of synthetic insecticides is a major public health challenge. Green nanoinsecticides are suitable alternatives to synthetic insecticides, enabling effective and safer insect control. This study aimed to develop neem oil-based nanoemulsions using Tween 80 and/or gum arabic (GA) as a natural emulsifiers and to study their larvicidal, and adulticidal activity against Culex pipiens. The fatty acids in the oil were identified using gas chromatographs-mass spectrometry (GC-MS). We also studied the acute oral toxicity on male rats and its ecotoxicological effects using the Microtox® assay. We fabricated neem oil nanoemulsions with and without GA at different ratios and performed physicochemical, stability, and characterization studies. The results showed that the major fatty acids in neem oil were oleic acid (44.79%), linoleic acid (18.41%), palmitic acid (18%), and stearic acid (16.64%). We created two highly stable nanoemulsions, i.e., samples 2C and 6C with a droplet sizes of 87.4 and 146.7 nm by mixing neem oil, GA, and Tween 80 at a ratio of 1:0:1.5, and 1:1.5:0, respectively, followed by sonication for 10 min. The lethal concentration (LC50) of neem oil, 2C and 6C were 9.36, 6.45, and 8.01 μg/ml for the Culex pipiens larvae and 21.7, 8.8 and 17.2 μg/ml for the adults. The toxicity time (T50) was 40.7, 10.0, and 28.9 min for normal neem oil, samples 2C and 6C, respectively. The nanoemulsions altered the toxifying-detoxifying enzymes acetylcholinesterase (AChE) and glutathione S-transferase (GST) in Culex pipiens larvae without showing any toxicity in the male rats or the Microtox assay. The neem oil nanoformulations with Tween 80 or GA were highly stable and effective against larval and adult Culex pipiens. GA is a natural-surfactant and hence, is excellent emulsifier alternative to synthetic surfactants. The nanoemulsions did not display any toxic and eco-toxic effects. Therefore, these nanoemulsions can be considered potential alternatives to synthetic insecticides for controlling vector-borne disease insects.

Progress in Synthesis of Glycidol

The molecular structure of glycidol contains two highly active chemical functional groups, epoxy group and hydroxyl group, so it is very active and is a very useful chemical substance. It can be used as plastics, fiber modifiers, epoxy resin diluents, halogenated hydrocarbon stabilizers, food preservatives, fungicides, etc. In the pharmaceutical field, it can be used to synthesize a series of blockers for cardiovascular diseases, HIV protease inhibitor for AIDS, antiviral drug, many lactones and glycerophospholipid, it can also be used as an important intermediate of some photoelectric materials and functional polymer materials. The partial reactivity of glycidyl depends on its epoxy ring acting as an alkylating agent. In addition, it is used in the production of flavorings and sweeteners. Glycidyl can also be used as a stabilizer, used in the production of petroleum, vinyl polymers, demulsifiers, dyeing layered agents and gelata applied in surface coatings, chemical synthesis, fungicides, solid fuels. It's also an important monomer and semi-finished product for synthetic surfactant. And its derivatives are also a kind of chemical raw materials, which are used in many fields such as resins, plastics, medicines, pesticides and auxiliaries. Therefore, more and more attention are paid to the synthesis and application of glycidol. However, the application of glycerol in our country is limited, and the industrial production is also lagging behind. In this paper, the process of glycidol synthesis form propylene alcohol and glycerol as basic raw material was reviewed, and the preparation of glycidol was systematically summarized, so as to provide reference for the subsequent research of glycidol.

BIOPROSES PENGURAIAN LIMBAH CAIR BUANGAN INDUSTRI PANGAN DAN NON-PANGAN BERBASIS BIOSURFAKTAN

Biosurfactants are microbial metabolites that may be utilized to replace synthetic chemical surfactant in overcoming the problem of industrial wastewater pollution. Indications of the presence of biosurfactant activity may be determined through measurement of emulsification and enzymatic activity of the tested microorganisms on their growth media, which is indicated by decreasing the BOD and COD of the tested growth media containing wastewater material as an inducer added to the microbial growth medium. This research was conducted to examine several potential microbial isolates that produce biosurfactants on growth media containing mixed waste water. The results showed that some of the microbial cultures tested showed the potential to produce biosurfactants as indicated by the emulsification and enzymatic activity of the tested microbial culture. Trial on mixed industrial wastewater showed that the tested biosurfactants were able to reduce the levels of BOD (440-1300 mg/l) and COD (1240-1760 mg/l) of the wastewater samples up to low BOD levels (82 mg/l) and COD (116 mg/l), respectively, thus that it meets the requirements of the established wastewater quality standards according to the Indonesian Standard regarding with the respective BOD (50-100 mg/l, 06-6989.9-2004 SNI) and COD (100-250 mg /l, 06-6989.2-2004 SNI).Key words : biosurfactant, emulsification, microbial enzyme, wastewater, BOD, COD.

Multi-method biophysical analysis in discovery, identification, and in-depth characterization of surface‐active compounds

Synthetic surfactants are used in several industries, including manufacturing, pharmaceutical and cosmetic’s, food and feed, agriculture, petroleum and environmental remediation for their ability to adsorb to fluid and solid-water interfaces. However, their widespread use and their synthetic preparation through environmentally unfavorable processes counterbalances the value of this class of reagents. This fact has stimulated new efforts to exploit natural sources of surfactants, such as new classes of bacterial systems or manipulation of existing biological systems, that may produce, through an environmentally friendly process, new biodegradable surfactants and emulsifiers of high commercial value. A downside of microbial production of biobased chemicals such as these types of chemicals, is that their fermentation often yields crude materials consisting of several bioproducts with complex physical and chemical properties. Extraction, identification, and efficient characterization of biosurfactants from a crude mixture of biomolecules requires carefully designed, and detailed analytical processes using state-of-the-art methods. The purpose of this review article is to present the current state-of-the-art and future outlook on the various multidisciplinary biophysical methods applied in the discovery, extraction identification, and in-depth characterization of microbially-produced surface‐active compounds.

Ex-situ bioremediation of petroleum hydrocarbon contaminated soil using mixed stimulants: Response and dynamics of bacterial community and phytotoxicity

Pollution of agricultural soils by excessive petroleum hydrocarbons (PHs) has recently become a severe worldwide environmental issue. Various approaches have been recently employed to biodegrade PHs and detoxify soils. In the present study, an experimental mesocosm was developed in a bioslurry reactor. Six treatments were applied to degrade PHs-and detoxify contaminated soil by adding external stimulants such as nutrients, activated sludge, synthetic surfactant, and long-chain rhamnolipids. The comparative analysis revealed that the combination of activated sludge, nutrients, and biosurfactant showed a 79.4% reduction in TPHs after 10 days in the mesocosm experiment. The lowest reduction in total PHs (48.5 %) was attained in the nutrient-supplied mesocosms. The consortia’s kinetic analyses of PHs revealed the lowest half-life time (t1/2 = 4.1 days), the highest biodegradation rate constants (k = 0.17 day1), and the reaction rate data from each bioremediation method was fitted with a first-order reaction rate model. The 16S rRNA gene amplicon and sequencing revealed that Streptomyces, Nocardioides, Arthrobacter, Pseudomonas, and Bacillus were the main oxidative species as PHs degraders. The highest relative abundances were in Arthrobacter, Pseudomonas, and Bacillus. The phytotoxicity studies proved that there was a significant decrease in the toxicity of soil after the biotreatment. According to the findings of this study, adding external stimulants such as activated sludge, nutrients, and biosurfactants enhanced the degradation of PHs in the soil in bioslurry enhancement as a promising approach to pilot scale.

Remediation of Heavy Metal-Contaminated Soils with Soil Washing: A Review

Soil with heavy metals’ contamination has caused worldwide concern, and there is an increasing interest in the application of washing agents for the remediation of soils with heavy metals’ contamination. The review summarizes the recent findings about soil washing with different washing agents. For soil washing technologies, the solubilizing capability, toxicity, and biocompatibility of agents are essential concerns. Washing agents can enhance heavy metals’ desorption and removal from soil. Inorganic acids/bases/salts, synthetic surfactants, and synthetic chelators are often limited due to their adverse effects on soil. Biosurfactants, HAs (humic acids), and LMWOA (low-molecular-weight organic acids) are suggested washing agents, but the limitation of their low production needs to be conquered. Moreover, both washing with a mixture agent and sequential washing have often been adopted to improve the overall capacity of the washing agent for decontamination. Mixture washing can obtain the synergetic effect for soil washing and increase washing efficiency. Sequential washing can apply an agent with a high heavy metals removal rate. However, this may cause environmental risks in the early stage, and then remove the washing agent injected in the early stage by the secondary washing stage. Overall, the already known cases reveal the good prospect of soil washing for soil remediation.

Hydrophobisation of Silica Nanoparticles Using Lauroyl Ethyl Arginate and Chitosan Mixtures to Induce the Foaming Process.

We studied silica suspensions with chitosan and biodegradable synthetic surfactant lauroyl ethyl arginate (LAE). Hydrophilic and negatively charged silica nanoparticles were neutralised due to the coating with chitosan. That presence of LAE led to the partial hydrophobisation of their surface, which favoured their attachment to the surface of a thin foam film. It was found that the presence of small and medium-sized (6–9 nm) hydrophobic particles in the interfacial layer of lamella foam film inhibited the coalescence and coarsening processes, which prolonged the life of the foam. Furthermore, hydrophobising of 30 nm particles allowed the formation of large aggregates precipitating from the mixture under steady-state conditions. These aggregates, however, under the conditions of the dynamic froth flotation process in the foam column, were floated into the foam layer. As a result, they were trapped in the foam film and Plateau borders, effectively preventing liquid leakage out of the foam. These results demonstrate the efficiency of using chitosan-LAE mixtures to remove silica nanoparticles from aqueous phase by foaming and flotation.

Approaches for increasing the electrocatalitic efficiency of cytochrome P450 3A4

The electrochemically driven cytochrome P450 reactions have great promise as drug sensing device, new drug searching tool and bioreactor with broad synthetic application. In the present work, we proposed approaches for the increasing the efficiency of cytochrome P450 3A4 electrocatalysis, based on fine regulation and reproduction of nature hemeprotein catalytic cycle and electron transfer pathways on electrode. To analyze the comparative electrochemical and electrocatalytic activity, cytochrome P450 3A4 was immobilized on electrodes modified with a membrane-like synthetic surfactant, didodecyldimethylammonium bromide (DDAB). We used riboflavin, FMN and FAD as low molecular models of NADPH-dependent cytochrome P450 reductase for the improving and enhancement properties of catalytically responsible cytochrome P450 3A4-electrode. The efficiencies of electrocatalysis of erythromycin N-demethylation as well-known cytochrome P450 3A4 substrate in the case of riboflavin, FAD and FMN as electron transfer mediators were 135 ± 6, 171 ± 15 and 203 ± 10 %, respectively (in comparison with 100 ± 18 % erythromycin N-demethylation in the case of cytochrome P450 3A4-electrode as catalyst). Molecular modeling of cytochrome P450 3A4 complexes with riboflavin, FMN and FAD confirms possibility of binding isoalloxazine ring of riboflavin to the protein on the proximal side of hemeprotein, which is the place for binding of redox partners of the cytochrome P450.

Effect of natural surfactant on the performance of reduced graphene oxide conductive ink

Conductive ink with stable dispersion and excellent printing properties can be produced using graphene-based nanomaterials and suitable solvents for flexible printed electronics applications. Eco-friendly water-based inks can be used as an alternative to organic solvents-based inks to minimize environmental impacts. Graphene oxide (GO) nanofillers can form stable aqueous dispersions and can be produced in bulk quantities using chemical exfoliation methods. Hence GO nanofillers can be used as a filler to produce water-based conductive ink for printed electronics applications. However, the higher surface tension and lower stability are major drawbacks which limit its printing properties. Natural surfactants can minimize these issues to ensure smooth printing with a higher shelf life as compared to harmful synthetic surfactants. This study aimed to investigate the role of natural-based surfactants such as gum arabic, cellulose nanocrystals and alkali lignin in producing stable and high performing water-based GO ink. The prepared ink samples were characterized for their wetting properties, printability, and storage time. The ink was also investigated for structural, functional groups, and stability. The printed patterns were investigated for morphological and electrical properties. The results from study indicate that the GO with alkali lignin surfactant gives long-term stability and better printing properties compared to other samples. The printed pattern after thermal reduction was found to have a conductivity of 833 S/m, which was reduced by only 2.6% after 100 bending cycles, whereas the electrical conductivity was reduced by only 0.6% after 10 rolling cycles indicating a great potential to be used in flexible electronic devices.

Synergistic effect and performance characterization of an efficient environmental-friendly Camellia oleifera saponins based foamed cleaning agents

Foamed cleaning agents mainly consist of synthetic surfactants. However, the widespread use of petroleum-based surfactants not only consumes non-renewable resources but also causes harm to the environment. It is necessary to develop surfactants with higher biodegradability and lower toxicity to obtain a recipe for an environment friendly foamed cleaning agent. Camellia oleifera saponins (TS) was prepared and mixed with a zwitterionic surfactant (dodecyl dimethyl sulfopropyl betaine, SB12-3). The equilibrium surface tension of single surfactants and their binary mixtures in the air/water system was measured using Wilhelmy method. The interaction and thermodynamic parameters of different mixtures were calculated via the regular solution model. The parameters showed that the mixtures displayed a synergistic effect, and the optimum molar ratio of TS/SB12-3 was determined to be 5/95. The mixture had the shortest wetting time (13 s), the smallest contact angle (32.4°), and the lowest surface tension (32.2 mN/m). Furthermore, the addition of TS significantly improved the emulsifying and foam properties. Cleaning experiments were completed by applying foamed surfactant solutions with different liquid fractions (ε) prepared by the double syringe technique on oil-contaminated glass substrates. The foamed surfactant solutions of the mixture were cleaner than those of TS or SB12-3 at all ε. The maximum oil area removal efficiency of the mixture was 94.9% at ε = 15%. The mixture exhibits a better cleaning efficiency than that of single surfactants. This study provides a new way for the utilization of Camellia oleifera cake.

Rhamnolipid Micellization and Adsorption Properties.

Biosurfactants are naturally occurring amphiphiles that are being actively pursued as alternatives to synthetic surfactants in cleaning, personal care, and cosmetic products. On the basis of their ability to mobilize and disperse hydrocarbons, biosurfactants are also involved in the bioremediation of oil spills. Rhamnolipids are low molecular weight glycolipid biosurfactants that consist of a mono- or di-rhamnose head group and a hydrocarbon fatty acid chain. We examine here the micellization of purified mono-rhamnolipids and di-rhamnolipids in aqueous solutions and their adsorption on model solid surfaces. Rhamnolipid micellization in water is endothermic; the CMC (critical micellization concentration) of di-rhamnolipid is lower than that of mono-rhamnolipid, and both CMCs decrease upon NaCl addition. Rhamnolipid adsorption on gold surface is mostly reversible and the adsorbed layer is rigid. A better understanding of biosurfactant self-assembly and adsorption properties is important for their utilization in consumer products and environmental applications.

Synthetic and biological surfactant effects on freshwater biofilm community composition and metabolic activity

Surfactants are used to control microbial biofilms in industrial and medical settings. Their known toxicity on aquatic biota, and their longevity in the environment, has encouraged research on biodegradable alternatives such as rhamnolipids. While previous research has investigated the effects of biological surfactants on single species biofilms, there remains a lack of information regarding the effects of synthetic and biological surfactants in freshwater ecosystems. We conducted a mesocosm experiment to test how the surfactant sodium dodecyl sulfate (SDS) and the biological surfactant rhamnolipid altered community composition and metabolic activity of freshwater biofilms. Biofilms were cultured in the flumes using lake water from Lake Lunz in Austria, under high (300 ppm) and low (150 ppm) concentrations of either surfactant over a four-week period. Our results show that both surfactants significantly affected microbial diversity. Up to 36% of microbial operational taxonomic units were lost after surfactant exposure. Rhamnolipid exposure also increased the production of the extracellular enzymes, leucine aminopeptidase, and glucosidase, while SDS exposure reduced leucine aminopeptidase and glucosidase. This study demonstrates that exposure of freshwater biofilms to chemical and biological surfactants caused a reduction of microbial diversity and changes in biofilm metabolism, exemplified by shifts in extracellular enzyme activities.Key points• Microbial biofilm diversity decreased significantly after surfactant exposure.• Exposure to either surfactant altered extracellular enzyme activity.• Overall metabolic activity was not altered, suggesting functional redundancy.

Effect of linking groups and hydrophobic groups on properties of sulfate Gemini surfactants

From the perspective of molecular design, a series of sulfate Gemini surfactants with different hydrophobic chains and linking groups were synthesized by etherification, ring opening and sulfation. The structures of the products were characterized by IR and 1H NMR. The synthesized sulfate Gemini surfactants had good heat resistance, especially the surfactants with rigid linking groups, measured by thermogravimetric analysis. The synthetic surfactants had low Krafft points, wherein the Krafft points of the surfactants with a carbon chain of 12 were <0 °C. With increasing hydrophobic carbon chain length or decreasing methylene number of linker, their CMC and γcmc first decreased and then increased. The γcmc of surfactants with rigid linking groups were higher and their CMCs were lower. It is analyzed by the calculated surface activity parameters (pC20, Γmax, Amin) that with increasing hydrophobic chain length, the surface activity of synthetic surfactants increased first and then decreased, and the surfactant with hydrophobic carbon chain C14 had the best surface activity. The influences of the length of the linking group and the hydrophobic group on the emulsifying capacity, wetting property, calcium soap dispersion and foam property of the surfactants were also analyzed. It was an attempt to explore and design excellent Gemini surfactants.

Biosurfactants in the sustainable eradication of SARS COV-2 from the environmental surfaces.

The COVID-19 outbreak has brought the world, at least, to one consensus that cleanliness is unavoidable under all circumstances. Hands are the main body part to interact with the environment and thus are prone to receive, initiate and propagate the chain of infection. Hand hygiene has, therefore, been most emphasized by experts to interrupt the spread of infection. Various harsh chemicals like synthetic surfactants and alcoholic preparations have been in practice to eradicate and disinfect the germs. This choice may be unsafe and cause a subsequent chain of adversities. Thereby, biosurfactants have been proposed as sustainable, non-toxic and safe surface cleaners cum disinfectants under a wide range of physiological and environmental conditions. The amphiphilic micellar behavior of biosurfactants makes them promising candidates as hygienic surface cleaners and therapeutic carriers. We overview the possibilities of using biosurfactants in different ways against microbial pathogens, in general, and the SARS COV-2, in specific.

Plant-derived saponin enhances biodegradation of petroleum hydrocarbons in the rhizosphere of native wild plants

Plant-derived saponins are bioactive surfactant compounds that can solubilize organic pollutants in environmental matrices, thereby facilitating pollutant remediation. Externally applied saponin has potential to enhance total petroleum hydrocarbon (TPH) biodegradation in the root zone (rhizosphere) of wild plants, but the associated mechanisms are not well understood. For the first time, this study evaluated a triterpenoid saponin (from red ash leaves, Alphitonia excelsa) in comparison to a synthetic surfactant (Triton X-100) for their effects on plant growth and biodegradation of TPH in the rhizosphere of two native wild species (a grass, Chloris truncata, and a shrub, Hakea prostrata). The addition of Triton X-100 at the highest level (1000 mg/kg) in the polluted soil significantly hindered the plant growth (reduced plant biomass and photosynthesis) and associated rhizosphere microbial activity in both the studied plants. Therefore, TPH removal in the rhizosphere of both plant species treated with the synthetic surfactant was not enhanced (at the lower level, 500 mg/kg soil) and even slightly decreased (at the highest level) compared to that in the surfactant-free (control) treatment. By contrast, TPH removal was significantly increased with saponin application (up to 60% in C. truncata at 1000 mg/kg due to enhanced plant growth and associated rhizosphere microbial activity). No significant difference was observed between the two saponin application levels. Dehydrogenase activity positively correlated with TPH removal (p < 0.001) and thus this parameter could be used as an indicator to predict the rhizoremediation efficiency. This work indicates that saponin-amended rhizoremediation could be an environmentally friendly and effective biological approach to remediate TPH-polluted soils. It was clear that the enhanced plant growth and rhizosphere microbial activity played a crucial role in TPH rhizoremediation efficiency. The saponin-induced molecular processes that promoted plant growth and soil microbial activity in the rhizosphere warrant further studies.

Formation and physical stability of hazelnut oil nanoemulsions: Comparison of a synthetic surfactant and a natural emulsifier

AbstractHazelnut oil is a significant edible oil with positive effects on human health. This study aimed to integrate hazelnut oil, which is known for its cardiovascular benefits, into nanoemulsion technology for the first time as an innovative conception, to maintain its stability against environmental conditions, and to benefit more by making it more bioaccessible. Polysorbate 80 and whey protein isolate (WPI) were used to stabilize the nanoemulsions. In this way, we aimed to show that WPI, a natural emulsifier, could be an alternative to the synthetic Polysorbate 80 emulsifier known for its high emulsification ability to stabilize hazelnut oil emulsions. The emulsions, formed by using a 2% (wt/wt) emulsifier and passed through a microfluidizer five times at 96.5 MPa pressure provided the small particle size (d32) as 296 ± 7.76 nm and 216 ± 1.78 nm for the WPI and Polysorbate 80‐stabilized samples, respectively. Polysorbate 80‐stabilized nanoemulsions were more physically stable under different pH, temperature, and ionic strength conditions compared with WPI‐stabilized nanoemulsions. Finally, the fates of the emulsions were investigated under a simulated in vitro digestion system. The increase in droplet sizes during the gastric phase was to a higher extent for the WPI‐stabilized nanoemulsions (d32 = 5.500 ± 0.60 μm) compared with Polysorbate 80‐stabilized emulsions (d32 = 1.069 ± 0.09 μm). Although hazelnut nanoemulsions stabilized with Polysorbate 80 showed higher physical stability, it was determined that WPI would also be successful in producing stable hazelnut oil‐in‐water emulsions, exhibiting FFA (%) values of 88%–90.5% in the small intestine.

Fluorescence and molecular signatures of dissolved organic matter to monitor and assess its multiple sources from a polluted river in the farming-pastoral ecotone of northern China.

The sources and composition of dissolved organic matter (DOM) in rivers are critical to water quality and aquatic ecosystems. Studies on detailed composition of organic matter in rivers in the farming-pastoral ecotone are relatively limited in the research community. To better understand the characteristics and dynamics of DOM, Yang River in North China was selected as the study area because of its profound influences on the farming-pastoral ecotone nearby. A combination of fluorescence spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) techniques revealed that the DOM composition of Yang River is driven by land use. DOM in Yang River is predominantly imported from allochthonous inputs, together with agricultural runoff, pastureland, and urban sewage, causing a comprehensive impact on DOM. In detail, DOM associated with cropland inputs was dominated by lignin-like species, with higher nitrogen content. In comparison, DOM related to grassland is more diverse and susceptible to degradation. An increase in urban areas led to an increase in sulfur-containing compounds, while their oxygen, nitrogen, and aromaticity contents were significantly lower than those in cropland. Interestingly, urban-influenced lignin-like compounds may be associated with the effluents from the pulp and paper mill. Additionally, synthetic surfactants from the lower section of the river were also structurally identified by tandem mass spectrometry. Overall, this study could provide valuable insights into the DOM sources and their transformation dynamics at a molecular level, which could be an indicator for riverine water quality management and be applied to other farming-pastoral ecotones straightforward.

DETERMINATION OF PHYSICAL STABILITY OF OMEGA-3 FATTY ACID NANOEMULSIONS AT DIFFERENT CONDITIONS

Bu çalışmada, omega-3 yağ asitlerince zengin balık yağı (%5) ve Tween 80 (T80), Quillaja Saponin (QS), Gam Arabik (GA) sürfaktanları (%1) kullanılarak mikroakışkanlaştırıcı yardımı ile su içinde yağ (Y/S) nanoemülsiyonları hazırlanmıştır. Nanoemülsiyonların fiziksel stabiliteleri; pH (4-7), sıcaklık (40-80oC) ve iyonik şiddet (0-500 mM NaCl) etkisi ile belirlenmiştir. Nanoemülsiyonların partikül boyutlarının 125±0.40 ile 542±0.45 nm ve partikül yüklerinin −12.80±0.63 ile −69.1±0.14 mV aralığında olduğu tespit edilmiştir. T80 ve QS ile stabilize edilen nanoemülsiyonların farklı pH, sıcaklık ve iyonik şiddet koşullarında fiziksel stabilitelerinin değişmediği görülmüştür. GA ile stabilize edilmiş nanoemülsiyonların ise pH, sıcaklık ve iyonik şiddet etkisine nispeten hassas olduğu ancak fiziksel stabilitesinde önemli bir değişiklik olmadığı görülmüştür. Sonuç olarak, omega-3 ile zenginleştirilmiş fiziksel olarak stabil nanoemülsiyonlar hem sentetik (T80) hem de doğal (QS ve GA) sürfaktanlar kullanılarak üretilmiştir. Elde edilen bu sonuçların omega-3 yağ asidi ile zenginleştirilmiş gıda üretimi ile ilgili çalışmalara katkı sağlayacağı düşünülmektedir.

Surface Properties and Biological Activities on Bacteria Cells by Biobased Surfactants for Antifouling Applications

Microfouling is the deposition of inorganic and organic material on surfaces and can cause economic losses. This deposition affects the performance of vessels, causes corrosion, clogging of equipment and contaminates the surfaces of medical items and the surface of machinery that handles food; it is controlled by cleaning products that contain synthetic surfactants in their formulations. Biobased products provide a promising basis to produce sustainable chemicals such as surfactants. In the present study, the biobased surfactants glyceryl laurate and hydroxystearic acid were synthesized and evaluated for stability at different pH values, salinity and temperatures. In addition, bioactivity tests against Pseudomonas aeruginosa (UCP 0992) and Bacillus cereus (UCP 1516) were also performed. Biobased surfactants glyceryl laurate and hydroxystearic acid showed excellent stability against temperature, pH, salinity and emulsifying activities for different kinds of oils; prevented bacterial adhesion by almost 100%; and affected the production of EPS by both bacteria and their consortium when compared to a synthetic surfactant SDS. The results showed the potential of these substances for application as an alternative antifouling non-biocide.

Micellar and sub-micellar chromatography with a cocamidopropyl betaine surfactant

We have coated a typical C18 column with the pH cationic charge controllable zwitterionic synthetic surfactant, cocamidopropyl betaine (CAPB), in order to generate a mixed mode reversed phase weak ion exchange column. As determined by the Thomas model, the column has an adsorbed surfactant capacity of 0.557 mmoles. The addition of 8.8 × 10–4 M CAPB to the totally aqueous mobile phase ensured stability of the surfactant on the column and permitted separation of the four component sulfonamide mixture with micellar liquid chromatography (MLC) in under 11 min. Comparatively, with a dilute H2SO4 mobile phase with no CAPB, the separation time for the sulfonamide mixture reached an excessive run time of an hour on the bare C18 chains. With CAPB in the mobile phase (no organic solvent present), a seven component sulfonamide mixture could be separated in less than 45 min. A five component short chain carboxylic acid mixture, separated in 20 min, was used to examine the ion exchange character of the column in pH environments of 2.3 and 4.6. Three phase MLC equilibrium analysis was also done in these pH environments with the sulfa drug and carboxylic acid mixtures to determine partition coefficients. Finally, a quite high molecular weight (70,000) anionic polystyrene sulfonate polymer was characterized by MLC with only CAPB and variable pH mobile phases; the optimal pH was determined to be 5.6. A totally aqueous mobile phase without CAPB was not suitable for profiling this polymer.