Utilization of Oil Industry Residues for the Production of Rhamnolipids by Pseudomonas indica

In the present work, a new strain Pseudomonas indica MTCC 3714 was studied for the production of biosurfactants using various rice‐bran oil industry residues viz. rice‐bran, de‐oiled rice‐bran, fatty acids and waxes. Among all the carbon sources, a maximum reduction in surface tension (26.4 mN/m) was observed when the media were supplemented with rice‐bran and the biosurfactant was recovered using the ultrasonication technique as one of the steps in the extraction process. Biosurfactants were obtained in yields of about 9.6 g/L using rice‐bran as the carbon source. The structure of the biosurfactants as characterized by FT‐IR, NMR (¹H and ¹³C) and LC–MS analysis revealed that the majority of the biosurfactants were di‐rhamnolipids. The biosurfactants produced were able to emulsify various hydrocarbons and showed excellent potential in microbial enhanced oil recovery, as it was able to recover kerosene up to 70 % in a sandpack test.     

Characterization of aescin as a biosurfactant for environmental remediation

Surface-tension-lowering capacity and emulsion-forming ability of aescin biosurfactant in pure water, seawater, 3 M urea, and 3 M glucose were investigated. Oils used in the emulsification tests were liquid paraffin, ethylbenzene, kerosene, 1-decene, and heavy oils A and C. Volumetric ratios of oil phase to aqueous (water) phase (O/W) were 0.5∶4.5, 2.5∶2.5, 3.0∶2.0, and 4.5∶0.5. Concentration of aescin was changed from 0.16 to 27.3 mM. The critical micelle concentration of eascin in water and its surface tension effectiveness were shown to be 0.78 mM and 28.5 mN/m, respectively. Surface-tension effectiveness of aescin was found to be highest in sea-water (33.5 mN/m). The emulsifying action of aescin was compared with that of decaglyceryl-monolaurylester (DGML). The performance of aescin was found to be as good as that of DGML and, depending on the O/W ratio and the concentration, aescin could yield emulsification efficiencies as high as 100%. These results indicated that aescin could be classified as a mild surfactant safe for living organisms. Because the surface activity of aqueous aescin solution was not satisfactorily good, attempts were made to improve the situation by addition of alcohols as cosurfactants. Ethanol, isoamyl alcohol, 2-ethylhexanol, n-hexanol, and n-octanol were used. They were added to the solutions at a concentration equimolar to aescin. These cosurfactants improved surface-tension effectiveness of aescin by as much as 53% and its emulsification efficiency by 67%.     

Biosurfactants Production Using Permeate from Whey Ultrafiltration and Bioproduct Recovery by Membrane Separation Process

The management of whey is a challenge for dairy products where the volume produced is remarkable. This problem is minimized through membrane separation processes (MSP) to obtain whey protein concentrate, which has high added value. However, a permeate effluent stream is still generated that is composed of lactose, vitamins, and minerals, which can serve as raw material for the production of biotechnological compounds. Thus, this study aimed to produce biosurfactants using the permeate from whey ultrafiltration as part of the culture media of the bioprocess, to recover the biosurfactant produced using MSP, and to identify the biocompound. The production was carried out using Bacillus methylotrophicus and Bacillus pumilus. The variables nitrogen source (urea or ammonium sulfate), nitrogen source concentration (0.5% or 1.0%), inducer (soybean oil or biodiesel), inducer concentration (1% or 2%), and the addition of micronutrients (with our without) were studied using a fractional factorial experimental design 2^5-1_IV. In the fermentation processes, it was possible to verify the biosurfactant production through the reduction of surface tension, obtaining a minimum value of 35.07 mN/m for B. methylotrophicus and 26.02 mN/m for B. pumilus. Recovery via MSP was an efficient strategy for biosurfactant purification, which was concentrated in the fraction of the retentate. We produced a high-value-added biocompound identified as surfactin, valuing the permeate residue from whey ultrafiltration.     

Utilization of molasses for biosurfactant production by two Bacillus strains at thermophilic conditions

Traditionally, biosurfactants have been produced from hydrocarbons. Some possible substitutes for microbial growth and biosurfactant production include urban wastes, peat hydrolysate, and agro-industrial by-products. Molasses, a nonconventional substrate (agro-industrial by-product) can also be used for biosurfactant production. It has been utilized by two strains of Bacillus subtilis (MTCC 2423 and MTCC1427) for biosurfactant production and growth at 45°C. As a result of biosurfactant accumulation, the surface tension of the medium was lowered to 29 and 31 dynes/cm by the two strains, respectively. This is the first report of biosurfactant production by strains of B. subtilis at 45°C. Potential application of the biosurfactant in microbial enhanced oil recovery is also presented.     

Effect of nutrients on optimal production of biosurfactants by <Emphasis Type="Italic">Pseudomonas putida</Emphasis>—A gujarat oil field isolate

Nutritional requirements for maximal production of biosurfactant by an oil field bacterium Pseudomonas putida were determined. The optimal concentrations of nitrogen, phosphate, sulfur, magnesium, iron, potassium, sodium, calcium, and trace elements for maximal production of biosurfactants were ascertained, and a new “Pruthi and Cameotra” salt medium was formulated. Data show that maximal biomass (2.4 g L⁻¹) and biosurfactant production (6.28 g L⁻¹) takes place after 72 h of growth on 2% hexadecane. The biosurfactant was produced optimally over pH and temperature ranges of 6.4–7.2 and 30–40°C, respectively. That the highest biosurfactant yield was obtained during late log phase of growth indicates that the biosurfactant is a secondary metabolite.     

Salt‐Free Aqueous Extraction of a Cell‐Bound Biosurfactant: a Kinetic Study

A cell‐bound biosurfactant produced by Lactobacillus pentosus was obtained under eco‐friendly conditions and used directly as an emulsifying agent in order to stabilize fluorene/water emulsions. The biosurfactant was extracted from L. pentosus cells with an aqueous phosphate buffer solution in the absence of NaCl. This is important because most the cell‐bound biosurfactants are extracted in the presence of NaCl, which is considered highly phytotoxic. A pseudo‐second order kinetic model best described the batch extraction of the biosurfactant from cells. As expected, the initial extraction rate of the biosurfactant increased with the temperature. Calculation of the activation energy with the Arrhenius equation yielded a positive value, indicating that the process is endothermic. The aqueous solution containing the biosurfactant was able to stabilize fluorene/water emulsions, with relative emulsion values of 62.2 % after 7 days of emulsion formation.     

十八烷基己基甲基羧基甜菜碱的合成及性能

以硬脂酸和己酸为原料合成了不对称双长链烷基羧基甜菜碱——十八烷基己基甲基羧基甜菜碱(C18+6B),测定了C18+6B的表面活性,并与总碳原子数相等的对称型双十二烷基甲基羧基甜菜碱(di C12B)进行比较,以了解表面活性剂分子结构对性能的影响。结果表明,C18+6B的表面活性与di C12B基本相当,但水溶性远好于di C12B。作为无碱驱油用表面活性剂,C18+6B对大庆原油来说HLB值略偏高,45℃下单独使用能将大庆原油/地层水界面张力降至10-2m N/m数量级,在大庆油砂上的饱和吸附量比di C12B低30%。C18+6B单独能将C7~C9正构烷烃/大庆地层水界面张力降至10-3m N/m数量级,而通过与亲油性更强的di C12B以及亲水性甜菜碱复配后,能将大庆原油/地层水界面张力降至10-3m N/m数量级,并能显著改善配方的水溶性。     

十八烷基己基甲基羧基甜菜碱的合成及性能

以硬脂酸和己酸为原料合成了不对称双长链烷基羧基甜菜碱——十八烷基己基甲基羧基甜菜碱(C18+6B),测定了C18+6B的表面活性,并与总碳原子数相等的对称型双十二烷基甲基羧基甜菜碱(diC12B)进行比较,以了解表面活性剂分子结构对性能的影响。结果表明,C18+6B的表面活性与diC12B基本相当,但水溶性远好于diC12B。作为无碱驱油用表面活性剂,C18+6B对大庆原油来说HLB值略偏高,45 ℃ 下单独使用能将大庆原油/地层水界面张力降至10-2mN/m数量级,在大庆油砂上的饱和吸附量比diC12B低30%。C18+6B单独能将C7~C9正构烷烃/大庆地层水界面张力降至10-3mN/m数量级,而通过与亲油性更强的diC12B以及亲水性甜菜碱复配后,能将大庆原油/地层水界面张力降至10-3mN/m数量级,并能显著改善配方的水溶性。     

Novel surfactants for ultralow interfacial tension in a wide range of surfactant concentration and temperature

This work investigates the possibility of injecting dilute aqueous solutions of novel surfactants into the Yibal field (Sultanate of Oman). This was accomplished through an experimental protocol based on the following criteria: (i) compatibility of the surfactants with the high-saline reservoir water (∼200 g/L); (ii) low interfacial tension (IFT) between crude oil and reservoir water (less than 10⁻² mN m⁻¹); and (iii) maintaining the low IFT behaviour during the entire surfactant flooding. Novel surfactants selected in this study consist of a series of ether sulfonates (AES-205, AES-128, AES-506, and 7–58) and an amphoteric surfactant (6–105). These surfactants were found to be compatible with reservoir water up to 0.1% surfactant concentration, whereas 6–105 and 7–58 showed compatibility within the full range of surfactant concentration investigated (0.001–0.5%). All surfactant systems displayed dynamic IFT behavior, in which ultralow transient minima were observed in the range 10⁻⁴–10⁻³ mN m⁻¹, followed by an increase in the IFT to equilibrium values in the range 10⁻³–10⁻¹ mN m⁻¹. The results also showed that with respect to concentration (0.05–0.5%) and temperature (45–80°C), AES-205 and 7–58 surfactants exhibit a wide range of applicability, with the IFT remaining below 10⁻² mN m⁻¹, as required for substantial residual oil recovery. In addition, ultralow IFT were obtained at surfactant concentrations as low as 0.001%, making the use of these surfactants in enhanced oil recovery extremely cost-effective.     

一株脂肽类生物表面活性剂产生菌的性能及其影响因素研究

通过对实验筛选出一株产脂肽类生物表面活性剂的菌株BW-23,进行性能及其影响因素研究.结果表明:脂肽表面活性剂的CMC浓度为70 mg/L时,表面张力为31.0 mN/m;发酵液稀释10倍后,乳化指数仍为24.72％;在10～60℃间菌株BW-23所产的生物表面活性剂的耐热性较好;菌株BW-23在pH值为5.0～8.0时表面活性最好;当NaCl浓度小于15％时,菌株BW-23水溶液的表面张力变化幅度最小;当Ca2+浓度达到5000 mg/L时,菌株BW-23水溶液的表面张力为30.5 mN/m.     

Biodegradability Study of the Biosurfactant Contained in a Crude Extract from Corn Steep Water

Over the last few years, the global biosurfactant market has raised due to the increasing awareness among consumers, for the use of biological or bio-based products. Because of their composition, it can be speculated that these are more biocompatible and more biodegradable than their chemical homologous. However, at the moment, no studies exist in the literature about the biodegradability of biosurfactants. In this work, a biosurfactant contained in a crude extract, obtained from a corn wet-milling industry stream that ferments spontaneously in the presence of lactic acid bacteria, was subjected to a biodegradation study, without addition of external microbial biomass, under different conditions of temperature (5–45 °C), biodegradation time (15–55 days), and pH (5–7). For that, a Box–Behnken factorial design was applied, which allowed to predict the percentage of biodegradation for the biosurfactant contained in the crude extract, between the range of the independent variables selected in the study, obtaining biodegradation values between 3 and 80%. The percentage of biodegradation for the biosurfactant was calculated based on the increase in the surface tension of samples of the crude extract. Furthermore, it was also possible to predict the variation in t_1/2 for the biosurfactant (time to achieve the 50% of biodegradation) under different conditions.     

Synthesis,characterization, and surface properties of phenylalanine-glycerol ether surfactants

A novel homologous series of 1-N-l-phenylalanine-glycerol ether surfactants was synthesized in satisfactory yields via reaction of epichlorohydrin with aliphatic alcohols with alkyl chains of 10–15 carbon atoms. Structural assignment of the new compounds was made on the basis of elemental analysis and spectroscopic data. Critical micelle concentration (CMC), surface tension at the CMC (γ_CMC), surfactant concentration required to reduce the surface tension of the solvent by 20 mN/m (pC₂₀), and the interfacial area occupied by the surfactant molecules (A_min) were determined from aqueous surface tension measurements using the Wilhelmy plate technique.     

Coal flotation using a biosurfactant from <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> as a frother

A biosurfactant-producing bacterial species (Pseudomonas aeruginosa) was grown in a mineral solution with gas oil as the source of carbon and energy. The biosurfactant was recovered from the solution by collecting the foam on the surface and drying. It had critical micelle concentration of 100 ppm. Froth characterization showed that the biosurfactant was superior to methyl isobutyl carbinol (MIBC) in terms of froth height and stability. The biosurfactant was examined in coal flotation as a frother. The combustible matter recovery of 72–79% with 10–15.5% ash content supporting 55–57.5% separation efficiency seemed promising enough to introduce the biosurfactant from Pseudomonas aeruginosa as a new frother.     

Chemical characterization and physicochemical behavior of biosurfactants

Microbes have been isolated from soil and water samples after an enrichment culture process with kerosene and tested for biosurfactant production by measuring the surface and interfacial tensions and emulsification power of culture broths. The isolation and characterization of extracellular surface-active agents from the culture broth of Pseudomonas aeruginosa 44T1 strain have been made. Preliminary structure identification with specific TLC reagents of the CHCl₃MeOH (2:1) extracts showed two spots with a glycolipidic structure and Rf values of 0.70 and 0.45, respectively, using the solvent system CHCl₃:MeOH:H₂O (65:25:4). Separation of surface active agents by Chromatographic absorption column in Florisil or silica gel and further spectroscopic study (IR, 1H-NMR, 13C-NMR) and chemical degradation techniques (acid and alkaline hydrolysis) gave a structure of β[β(2-0-α-L-rhamnopyranosyloxy)decanoyl] decanoic acid and β[β (2-0-α-L-rhamnopyranosyl-α-L-rhamnopyranosyloxy) decanoyloxy] decanoic acid (glycolipid A and glycolipid B, respectively) for the two glycolipids detected. A new method of mass spectrometry, fast atom bombardment mass spectrometry (FABMS), was used to probe molecular structure. The mass spectra obtained contain molecular weight recognition and sequence information signals, and they are in agreement with the proposed structures. Physicochemical evaluations of the two isolated glycolipids were made. The minimum surface tension obtained was 25 mN/m in water solutions. At pH 7 the CMC value was 11 ppm. In both cases, at pH 3 the CMC was displaced to lower and at pH 9 it was displaced to higher concentration values. Glycolipid B showed a lower value of interfacial tension (0.2 mN/m) than glycolipid A (1.0 mN/m). Glycolipid A showed a lower CMC value at alkaline pH, whereas glycolipid B had a lower CMC at acidic pH than at alkaline pH.     

Surface activity of mixtures of oxyethylated methyl dodecanoate and sodium dodecylbenzenesulfonate

Surface and interfacial tension and detergency of mixtures containing oxyethylated methyl dodecanoate and sodium dodecylbenzenesulfonate were determined. Synergism in the surface tension reduction was not observed. The competition for adsorption at the air/water interface between oxyethylated methyl dodecanoate and sodium dodecylbenzenesulfonate depended on the considered surface tension, the weight ratio of surfactants in the aqueous phase, and the hydrophile-lipophile balance of the nonionic surfactant. Generally, coverage of the interface with oxyethylated methyl dodecanoate increased when surface tension decreased. Nonionics were the dominant species at the interface in the important region of surface activity, i.e., for surface tensions below 40 mN m⁻¹. The mole fraction of the hydrophobic nonionic at the interface was higher than the contribution of hydrophilic oxyethylates. An increase of the surfactant ratio in the bulk phase affects the interfacial ratio of surfactants in the same way. The lowest interfacial tension (1.5 mN m⁻¹) at the hexadecane/water interface was observed for oxyethylated methyl dodecanoate having an average degree of oxyethylation equal to 8 and 10. Nearly 5 min was needed to achieve equilibrium value. Mixtures with sodium dodecylbenzenesulfonate decreased the interfacial tension somewhat less efficiently but the equilibrium was rapidly established. The standard washing powders containing oxyethylated methyl dodecanoates exhibited washing ability similar to that obtained for the powder with traditional alcohol oxyethylate.     

Ionic Behavior Assessment of Surface-Active Compounds from Corn Steep Liquor by Exchange Resins

Depending on their ionic nature, biosurfactants can be classified as nonionic, anionic, cationic, or amphoteric. The ionic behavior of biosurfactants is an important characteristic that dictates their use in industrial applications. In this work, a biosurfactant extract obtained from corn steep liquor was subjected to anionic or cationic resins, in order to study the ionic behavior under different operational conditions using response surface methodology. The independent variables included in the study are the dilution of biosurfactant solution, the amount of cationic or anionic resin, and the extraction time, whereas the dependent variables studied consisted of the surface tension of biosurfactant aqueous solution, after contacting with anionic or cationic resin. The results showed that biosurfactant extracted from corn steep liquor is amphoteric, since both resins were able to entrap this biosurfactant, making it particularly suited for use in personal care preparations for sensitive skin.     

沥青质模型油/MD膜驱剂溶液的界面张力

从MD膜驱剂与原油界面活性组分沥青质模型油的界面张力出发,考察了作用时间、水相pH、MD膜驱剂质量浓度、盐浓度、沥青质含量、芳香度、温度等对模型油/水界面张力的影响,并根据扩散控制机理解释了动态界面张力初期过程,进一步揭示了MD膜驱油技术的机理。结果表明,沥青质模型油/MD膜驱剂溶液的界面张力先随时间增加而降低,约15min后达到平衡,达到平衡之前的过程基本上符合扩散控制过程;MD膜驱剂的加入并不能改变pH对模型油/水界面张力的影响趋势;在所考察的条件范围内,沥青质模型油/水溶液的界面张力不随MD膜驱剂质量浓度增加而改变,其值约为19 65mN/m;NaCl对界面张力的影响不明显;沥青质质量浓度从0增加到1000mg/L时,模型油/水和模型油/MD膜驱剂溶液的界面张力分别从23 4mN/m和22 0mN/m逐渐下降至20 0mN/m和18 8mN/m;温度从25℃升高到45℃时,模型油/水溶液的界面张力降低;但芳香度从0增加到100%时,其界面张力均从21 0mN/m增加至31 5mN/m。MD膜驱剂是表面非活性物质,在驱油时不存在低界面张力提高采收率的机理。     

Synthesis, characterization and surface properties of 1-N-l-tryptophan-glycerol-ether surfactants

A novel homologous series of 1-N-l-tryptophanglycerol-ether surfactants was synthesized and characterized. The precursor compounds, 3-alkyloxy-1-chloropropan-2-ols, were prepared from epichlorohydrin and aliphatic alcohols with alkyl chain lengths of 9–16 carbon atoms. Tryptophan was then attached to the monosubstituted glycerol backbone from its α-amino group through an α-NH-C bond. Structural assignment of the new compounds was made on the basis of elemental analysis and spectroscopic data. Critical micelle concentrations of the new surfactants, as well as the negative logs of the surfactant concentrations required to reduce the surface tension of the solvent by 20 mN/m (pC ₂₀) and the interfacial areas occupied by the surfactant molecules, were calculated from aqueous surface tension measurements using the Wilhelmy plate technique.     

Characterizations of surfactant synthesized from Jatropha oil and its application in enhanced oil recovery

Surfactants are frequently used in chemical enhanced oil recovery (EOR) as it reduces the interfacial tension (IFT) to an ultra‐low value and also alter the wettability of oil‐wet rock, which are important mechanisms for EOR. However, most of the commercial surfactants used in chemical EOR are very expensive. In view of that an attempt has been made to synthesis an anionic surfactant from non‐edible Jatropha oil for its application in EOR. Synthesized surfactant was characterized by FTIR, NMR, dynamic light scattering, thermogravimeter analyser, FESEM, and EDX analysis. Thermal degradability study of the surfactant shows no significant loss till the conventional reservoir temperature. The ability of the surfactant for its use in chemical EOR has been tested by measuring its physicochemical properties, viz., reduction of surface tension, IFT and wettability alteration. The surfactant solution shows a surface tension value of 31.6 mN/m at its critical micelle concentration (CMC). An ultra‐low IFT of 0.0917 mN/m is obtained at CMC of surfactant solution, which is further reduced to 0.00108 mN/m at optimum salinity. The synthesized surfactant alters the oil‐wet quartz surface to water‐wet which favors enhanced recovery of oil. Flooding experiments were conducted with surfactant slugs with different concentrations. Encouraging results with additional recovery more than 25% of original oil in place above the conventional water flooding have been observed. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2731–2741, 2017     

Glucamine-based gemini surfactants I: Gemini surfactants from long-chain <Emphasis Type="Italic">N</Emphasis>-alkyl glucamines and α,ω-diepoxides

N-Alkyl glucamines can be reacted with α,ω-diepoxides to yield gemini (dimeric) surfactants similarly to the reaction of glucamine with terminal epoxides. Under the conditions chosen for this work, epoxides were quantitatively converted in the presence of an equimolar amount of amine to gemini surfactants. Reactions could be carried out under mild conditions (70°C) in methanol, and products were obtained quantitatively by removing the solvent. The combination of N-octyl glucamine, N-decyl glucamine, or N-dodecyl glucamine with diepoxides of α,ω-diolefins having chain lengths of C₈, C₉, C₁₀, or C₁₄ resulted in gemini surfactants differing in spacer length and length of hydrophobic alkyl chains. Surface-active properties were studied by measuring surface tension and evaluating foaming properties. Tensiometric studies showed the reduction of surface tension down to 29–33 mN/m and critical micelle concentrations often in the range of 3–150 mg/L. Comparison of a selected gemini surfactant [1,8-bis(N-dodecyl glucamino-2,7-octane diol] with its corresponding “single surfactant” demonstrated the enhancement of surface-active properties afforded by the gemini structure.