Introduction: This study assesses the environmental impacts of mannosylerythritol lipids (MELs) production for process optimization using life cycle assessment (LCA). MELs are glycolipid-type microbial biosurfactants with many possible applications based on their surface-active properties. They are generally produced by fungi from the family of Ustilaginaceae via fermentation in aerated bioreactors. The aim of our work is to accompany the development of biotechnological products at an early stage to enable environmentally sustainable process optimization. Methods: This is done by identifying hotspots and potentials for improvement based on a reliable quantification of the environmental impacts. The production processes of MELs are evaluated in a cradle-to-gate approach using the Environmental Footprint (EF) 3.1 impact assessment method. The LCA model is based on upscaled experimental data for the fermentation and purification, assuming the production at a 10 m³ scale. In the case analyzed, MELs are produced from rapeseed oil and glucose, and purified by separation, solvent extraction, and chromatography. Results: The results of the LCA show that the provision of substrates is a major source of environmental impacts and accounts for 20% of the impacts on Climate Change and more than 70% in the categories Acidification and Eutrophication. Moreover, 33% of the impacts on Climate Change is caused by the energy requirements for aeration of the bioreactor, while purification accounts for 42% of the impacts respectively. For the purification, solvents are identified as the main contributors in most impact categories. Discussion: The results illustrate the potentials for process optimization to reduce the environmental impacts of substrate requirements, enhanced bioreactor aeration, and efficient solvent use in downstream processing. By a scenario analysis, considering both experimental adaptations and prospective variations of the process, the laboratory development can be supported with further findings and hence efficiently optimized towards environmental sustainability. Moreover, the presentation of kinetic LCA results over the fermentation duration shows a novel way of calculating and visualizing results that corresponds to the way of thinking of process engineers using established environmental indicators and a detailed system analysis. Altogether, this LCA study supports and demonstrates the potential for further improvements towards more environmentally friendly produced surfactants.

Remediation of environmental oil pollution with the usage of fungal organisms has proven to be a successful cleanup bioremediation method for organic contaminants. To investigate the breakdown of oil pollutants in water environments, biosurfactant-producing fungi have been isolated from oil-polluted soil samples. 16s rRNA sequencing technique was performed to identify the fungal organism and phylogenetic tree has been constructed. A variety of biosurfactant screening tests have demonstrated the better biosurfactant producing ability of fungi. The emulsion\'s stability, which is essential for the biodegradation process, was indicated by the emulsification index of 68.48% and emulsification activity of 1.3. In the isolated biosurfactant, important functional groups such as amino groups, lipids, and sugars were found according to thin layer chromatography analysis with a maximum retention value of 0.85. A maximum oil degradation of around 64% was observed with immobilized beads within 12 days. The half-life, and degradation removal rate constant of 20.21 days and 0.03 day-1, respectively, have been determined by the degradation kinetic analysis. GCMS analysis confirmed the highly degraded hydrocarbons such as nonanoic acid and pyrrolidine. The immobilized fungi exhibit better oil biodegradability in aqueous solutions.

The effluent produced in refineries is in the form of an oil/water emulsion that must be treated. These emulsions are often stable and a suitable method must be used to separate the oil from the emulsion. Recently, biosurfactants or biodemulsifiers have received much attention to reduce the interfacial tension between two liquids. Biodemulsifiers are produced by microorganisms and have several benefits over chemical demulsifiers such as low-toxic, biodegradability, eco-friendly and easy synthesis. They can eliminate two phases by changing the interfacial forces between the water and oil molecules. Biosurfactants are categorized based on the molecular weight of their compounds (low or high molecular weight). Sophorolipids, lipopeptides rhamnolipids, trehalolipids, glycolipid, lipoproteins, lichenysin, surfactin, and polymeric biosurfactants are several types of biosurfactants, which are produced by bacteria or fungi. This review study provides a deep evaluation of biosurfactants in the demulsification process. To this end, different types of biosurfactants, the synthesis method of various biosurfactants using various microorganisms, features of biosurfactants, and the role of biodemulsifiers in the demulsification process are thoroughly discussed. Also, the impact of various efficient factors like pH, microorganism type, temperature, the oil content in the emulsion, and gravity on biodemulsificaion was studied. Finally, the mechanism of the demulsification process was discussed. According to previous studies, rhamnolipid biodemulsifier showed the highest biodemulsification efficiency (100%) in the removal of oil from an emulsion.

OBJECTIVE: Pseudomonas aeruginosa dirhamnolipid (diRL) has been shown to form aggregates of different size and structure, under various conditions. Due to the presence of a carboxyl group in the molecule, it is expected that pH would strongly affect this aggregation behaviour. In addition, preliminary observations of temperature-induced changes in the states of aggregation of diRL supported the need of further investigation.
METHODS: A systematic experimental study, using differential scanning calorimetry (DSC), small-angle Xray diffraction (SAXD), and Fourier-transform infrared spectroscopy (FTIR), has been carried out to characterize pH and temperature driven changes in the aggregation behavior of diRL biosurfactant. Molecular dynamics (MD) simulations, supported by the experimental results, allowed depicting molecular details on formation of diRL membranes and other aggregated structures under various physicochemical conditions.
RESULTS: DiRL could adopt fairly organized multilayered structures (membranes) at low pH and temperature, which became highly disordered upon increasing either of these parameters. The effect of pH on the gauche/all-trans conformer ratio of the diRL acyl chains was not of significance, whereas temperature-induced effects were observed. For the first time it is described that diRL underwent an endothermic thermotropic transition with Tc = 34 °C as observed by DSC, at pH 4.5 (protonated diRL), but not at pH 7.4 (unprotonated diRL). FTIR confirmed these findings, showing a significant additional disordering of the all-trans acyl chains upon increasing temperature around that same value in the protonated form, an effect not observed for the dissociated form of the biosurfactant. In addition, at pH 7.4, changing temperature did not modify the hydration state of the polar moiety of diRL, whereas at pH 4.5 a significant decrease in the hydration state around 34 °C took place. SAXD data showed that protonated diRL formed multilayered structures at 20 °C, which converted into poorly correlated layers at 50 °C. MD simulations supported these findings, showing that the membrane-like structures formed by protonated diRL at 20 °C became unstable at higher temperatures, tending to form other structures, which could be micelles or other type of layered structures, whereas the negatively charged form of diRL organized in micelle-type aggregates in the whole range of temperature under study.

Peri-implant mucositis and peri-implantitis are biofilm-related diseases causing major concern in oral implantology, requiring complex anti-infective procedures or implant removal. Microbial biosurfactants emerged as new anti-biofilm agents for coating implantable devices preserving biocompatibility. This study aimed to assess the efficacy of rhamnolipid biosurfactant R89 (R89BS) to reduce Staphylococcus aureus and Staphylococcus epidermidis biofilm formation on titanium.
R89BS was physically adsorbed on titanium discs (TDs). Cytotoxicity of coated TDs was evaluated on normal lung fibroblasts (MRC5) using a lactate dehydrogenase assay. The ability of coated TDs to inhibit biofilm formation was evaluated by quantifying biofilm biomass and cell metabolic activity, at different time-points, with respect to uncoated controls. A qualitative analysis of sessile bacteria was also performed by scanning electron microscopy.
R89BS-coated discs showed no cytotoxic effects. TDs coated with 4 mg/mL R89BS inhibited the biofilm biomass of S. aureus by 99%, 47% and 7% and of S. epidermidis by 54%, 29%, and 10% at 24, 48 and 72 h respectively. A significant reduction of the biofilm metabolic activity was also documented. The same coating applied on three commercial implant surfaces resulted in a biomass inhibition higher than 90% for S. aureus, and up to 78% for S. epidermidis at 24 h.
R89BS-coating was effective in reducing Staphylococcus biofilm formation at the titanium implant surface. The anti-biofilm action can be obtained on several different commercially available implant surfaces, independently of their surface morphology.

The present study evaluated the surfactin production by Bacillus subtilis UFPEDA 438 using sugarcane molasses as a substrate. The effects of the cultivation conditions (temperature, agitation and aeration ratio) on the biosurfactant production and kinetic parameters were investigated. Characteristics of the biosurfactant were obtained after analyses of the emulsification index (EI) and critical micellar concentration (CMC) of the fermentation broth. The results showed that in relation to the product its formation kinetics is strongly affected by operational conditions. It was also observed that surfactin production can be partially dependent or fully independent on microbial growth. The maximum values of surfactin concentration (199.45 ± 0.13 mg/L) and productivity (8,187 mg/L.h) were obtained in the culture under cultivation time of 24 h, temperature of 36 °C, agitation of 100 rpm and aeration ratio of 0.4. Under optimal conditions, the fermentation broth achieved good emulsification capacity (EI >40%) and CMC value of 20.73 mg/L. The results revealed that Bacillus subtilis UFPEDA 438 is a good producer of biosurfactant and that sugarcane molasses is a viable substrate for the production of surfactin.

Surfactants play a very important role in laundry and household cleaning products ingredients. In this research, the application of lipopeptide biosurfactants, produced by Bacillus subtilis SPB1, in the formulation of a washing powder was investigated. The SPB1 biosurfactant was mixed with sodium tripolyphosphate as a builder and sodium sulfate as filler. The efficiency of the formulated detergent composition with different washing conditions to remove a stain from cotton fabric was examined. The results showed that the formulated detergent was effective in oil removal, with optimal washing conditions of pH, temperature, striate and time of washing system of 7, 65°C, 1000 RPM and 60 min, respectively. A comparative study of different detergent compositions (biosurfactant-based detergent, combined biosurfactant-commercial detergent, and a commercial detergent) for the removal of oil and tea stains, proved that the bio-scouring was more effective (>75%) in terms of the stain removal than the commercial powders (<60%). Moreover, the results demonstrated that the biosurfactant acts additively with a commercial detergent and enhances their performance from 33 to 45% in removing oil stain and from 57 to 64% in removing tea stain. As a conclusion, in addition to the low toxicity and the high biodegradability of the microbial biosurfactants, the results of this study have shown that the future use of this lipopeptide biosurfactant as laundry detergent additive is highly promising.

OBJECTIVE: The main objective of this paper is to understand the rheological impact of rhamnolipids biosurfactant (mono/dirhamnolipids mixture, CCB) on a common personal care mixed surfactants system: anionic sodium laureth sulfate (SLES) and zwitterionic cocamidopropyl betaine (CAPB). The ternary biosurfactant/surfactants mixtures were evaluated at three different formulation conditions. The experimental results can provide a formulation guideline when applying rhamnolipids in cosmetics and personal care products.
METHODS: Traditional mechanical rheometer was used to measure bulk viscosity and lower frequency rheological behaviour of ternary surfactant mixtures. Diffusing wave spectroscopy (DWS) was utilized to access rheological responses at high frequency regime. Structural parameters such as contour length, entanglement length and persistence length of wormlike micelles in the anionic/zwitterionic/biosurfactant mixtures can be extracted from the rheological data gathered by DWS.
RESULTS: Maxwellian type response was present in SLES/CAPB/CCB system which indicated the formation of wormlike micelle. Contour length of wormlike micelle formed by SLES/CAPB reduced from 445.8 to 88.37 nm with only 2 wt% addition of CCB. In the same system, viscosity decreased and shorter relaxation time were observed. Addition of sodium chloride built the viscosity of SLES/CAPB/CCB to an extent by screening charges between surfactant head groups. Highest viscosity of SLES/CAPB/CCB (10 wt%, 2wt% and 4wt% respectfully) was observed when sodium chloride concentration was at 4 wt%. In the same SLES/CAPB/CCB system, pH impacted the system\'s rheological response significantly. Due to the zwitterionic nature of CAPB, it became more cationic at lower pH while rhamnolipids became more nonionic. SLES still maintained its anionic nature at low pH and this promoted the interaction between CAPB and SLES. At lower pH, overall loss and storage modulus exhibited higher values while longer relaxation times were observed. Increase in micelles contour length under lower pH conditions were shown by the DWS data.
CONCLUSIONS: This preliminary rheological and microstructure study of the complex biosurfactant/surfactants ternary systems revealed the effect of formulation conditions on the mixtures rheological responses.
OBJÉCTIF: L\'objectif principal de cet article est de comprendre l\'impact rhéologique du biosurfactant rhamnolipides (mixture de mono/dirhamnolipides, CCB) sur une crème de soin utilisant un système de surfactant mixtes: anionique (Sodium Laureth Sulfate, SLES) et zwitterionic (Cocamidopropyl bétaïne, CAPB). Les mélanges ternaires de biosurfactants et de tensioactifs ont été évalués dans trois conditions de formulation différentes. Les résultats expérimentaux peuvent prévoir des règles de formulation lors de l\'application de rhamnolipides dans des produits cosmétiques et des produits de soins personnels. MÉTHODÉS: Un rhéomètre mécanique traditionnel a été utilisé pour mesurer la viscosité apparente et le comportement rhéologique à basse fréquence du mélange tensioactif ternaire. La spectroscopie à ondes diffuses (DWS) a été utilisée pour l\'accès à des réponses rhéologiques en régime hautes fréquences. Les paramètres structurels tels que la longueur du contour, la longueur de l\'enchevêtrement et la longueur de la persistance des micelles de type ver dans les mixtures de anionique/zwitterionique/biosurfactant peuvent être calculés à l\'aide des données recueillies par DWS. RÉSULTATS: La réponse de type maxwellienne était présentée dans le système SLES / CAPB / CCB et indiquait la formation de micelles de type ver. La longueur de contour de la micelle formée par SLES/CAPB a été réduite de 445,8 à 88,37 nm avec seulement 2 wt% d\'ajout de CCB. Dans ce système, la viscosité a diminué et un temps de relaxation plus court a été observé. L\'ajout de chlorure de sodium a permis d\'augmenter la viscosité de SLES/CAPB/CCB en filtrant les charges entre les groupes de tête de tensioactif. La viscosité la plus élevée de SLES/CAPB/CCB (10 wt%, 2 wt% et 4 wt%, respectivement) a été observée lorsque la concentration de chlorure de sodium était à 4 wt%. Dans le même système SLES/CAPB/CCB, le pH a eu un impact significatif sur la réponse rhéologique du système. En raison de la nature zwitterionique du CAPB, il est devenu plus cationique à un pH plus bas tandis que les rhamnolipides sont devenus plus non ioniques. Le SLES conservait toujours sa nature anionique à un pH faible, ce qui favorisait l\'interaction entre le CAPB et le SLES. À un pH inférieur, la perte totale et le module de conservation affichaient des valeurs plus élevées, tandis que des temps de relaxation plus longs étaient observés. Les données du DWS montrent une augmentation de la longueur du contour des micelles dans des conditions de pH plus bas. CONCLUSION: Cette étude rhéologique et microstructurale préliminaire du système ternaire complexe biosurfactant/tensioactif a révélé l\'effet des conditions de formulation sur les réponses rhéologiques du mélange.

One of the most important challenges for pharmaceutical and cosmetic industries is solubilization and preservation of their active ingredients. Therefore, most of these formulations contain irritant chemical additives to improve their shelf-life and the solubility of hydrophobic ingredients. An interesting alternative to chemical surfactants and preservatives is the use of biosurfactants; thus, their surfactant properties and composition make them more biocompatible than their chemical counterparts. Moreover, some biosurfactants have shown antimicrobial activity in addition to their detergent capacity. In this work, the antimicrobial and irritant effect of 2 biosurfactant extracts was studied: one produced in a controlled fermentation process with Lactobacillus pentosus and the other produced from corn stream by spontaneous fermentation. The results showed a strong antimicrobial activity of the biosurfactant extract obtained from corn stream on pathogenic bacteria, in comparison with the L. pentosus biosurfactant extract. Moreover, both biosurfactants did not produce any irritant effect on the chorioallantoic membrane of hen\'s egg assay contrary to sodium dodecyl sulfate. This is the first study dealing with the application of biosurfactant extracts on sensitive biological membranes, and this is the first time that the preservative capacity of a biosurfactant extract obtained in spontaneous fermentation is being evaluated, achieving promising results.

OBJECTIVE: Vitamin E has interesting biological functions for the cosmetic and pharmaceutical industry because it can act as a fat-soluble antioxidant, as well as peroxyl radical scavenger. However, this vitamin is formed by a group of compounds that include tocopherols (γ-tocopherols, α-tocopherol) characterized by their poor solubility in water, what implies the need of using stabilizing agents such as biosurfactants or minerals, in order to make them soluble or stable in formulations composed by water and oil.
METHODS: In this work, it has been evaluated the synergic effect between a mining silicate mineral (mica) and a biosurfactant extract, obtained from corn steep liquor, to stabilize emulsions containing water and a non-aqueous soluble antioxidant consisting of Vitamin E, through the use of a triangular design.
RESULTS: The results show that the presence of biosurfactant extract improves the emulsion volume up to 70% after 22 days, for an emulsion composed of Vitamin E and biosurfactant, whereas the mica component was able to increase the emulsion stability until values of 80% after 30 days of experiment, for those emulsions containing 10% of mica. Hence, both novel ingredients produce a synergistic effect on the Pickering emulsions carried out in the study.