Potential therapeutic applications of biosurfactants

Metal-Biosurfactant Complexes Characterization: Binding, Self-Assembly and Interaction with Bovine Serum Albumin

Studies on the specific and nonspecific interactions of biosurfactants with proteins are broadly relevant given the potential applications of biosurfactant/protein systems in pharmaceutics and cosmetics. The aim of this study was to evaluate the interactions of divalent counterions with the biomolecular anionic biosurfactant surfactin-C₁₅ through molecular modeling, surface tension and dynamic light scattering (DLS), with a specific focus on its effects on biotherapeutic formulations. The conformational analysis based on a semi-empirical approach revealed that Cu²⁺ ions can be coordinated by three amide nitrogens belonging to the surfactin-C₁₅ cycle and one oxygen atom of the aspartic acid from the side chain of the lipopeptide. Backbone oxygen atoms mainly involve Zn²⁺, Ca²⁺ and Mg²⁺. Subsequently, the interactions between metal-coordinated lipopeptide complexes and bovine serum albumin (BSA) were extensively investigated by fluorescence spectroscopy and molecular docking analysis. Fluorescence results showed that metal-lipopeptide complexes interact with BSA through a static quenching mechanism. Molecular docking results indicate that the metal-lipopeptide complexes are stabilized by hydrogen bonding and van der Waals forces. The biosurfactant-protein interaction properties herein described are of significance for metal-based drug discovery hypothesizing that the association of divalent metal ions with surfactin allows its interaction with bacteria, fungi and cancer cell membranes with effects that are similar to those of the cationic peptide antibiotics.

Microbial Surfactants: Alternative to Vegetable Oil Surfactants

Biosurfactants, surface active molecules synthesized by microorganisms, represent a promising alternative to the synthetic surfactants in many different applications. Among them, rhamnolipids have attracted considerable attention in the last years due to their extraordinary surface-active properties and biological activities. Rhamnolipids are usually synthesized by the gram-negative bacterium Pseudomonas aeruginosa as complex mixtures of different congeners. In this chapter, we describe the most common techniques that can be used for the production, recovery and purification of rhamnolipids, using two sequential chromatographic techniques to recover and separate the monorhamnolipid and dirhamnolipid congeners.

Exogenous addition of alkanoic acids enhanced production of antifungal lipopeptides in Bacillus amyloliquefaciens Pc3

The bacterium, Bacillus amyloliquefaciens Pc3, was previously isolated from Antarctic seawater and has been found to show antagonistic activity against the fungus, Rhizoctonia solani ACCC 36316, which causes a severe disease known as Sclerotinia sclerotiorum in rapeseed plants. Bacillus lipopeptides had been widely used as biocontrol agents for plant diseases. In this study, we isolated 11 lipopeptide compounds from B. amyloliquefaciens Pc3 culture broth via reversed-phase high-performance liquid chromatography (RP-HPLC) and used matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) to identify these as iturin A (C₁₄, C₁₅, C₁₆, C₁₇), fengycin B (C₁₄, C₁₅, C₁₆, C₁₇), and surfactin (C₁₄, C₁₅, C₁₆). We further found that the addition of exogenous alkanoic acids, including myristic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, octadecanoic acid, and nonadecanoic acid, to the bacterial growth media could promote lipopeptide production and enhance the antifungal activities of crude lipopeptide extracts from B. amyloliquefaciens Pc3. In addition, the transcriptional levels of three lipopeptide synthesis genes, ituD, fenA, and srfA-A, and two fatty acid metabolism-related genes, FabI, which encodes enoyl-ACP reductase, and FadB, which encodes enoyl-CoA hydratase, were found to be upregulated in cells grown with exogenous alkanoic acids. Among the six alkanoic acids tested, those with odd carbon chain lengths had a greater effect on lipopeptide production, antifungal activity, and target gene upregulation than those with even carbon chain lengths. These results provide a practical approach for the efficient production of lipopeptides in Bacillus amyloliquefaciens Pc3.

Liposomes containing biosurfactants isolated from Lactobacillus gasseri exert antibiofilm activity against methicillin resistant Staphylococcus aureus strains

Staphylococcus aureus is the major causative agent of skin and soft tissue infections, whose prevention and treatment have become more difficult due to the emergence of antibiotic-resistant strains. In this regard, the development of an effective treatment represents a challenge that can be overcome by delivering new antibiofilm agents with appropriate nanocarriers. In this study, a biosurfactant (BS) isolated from Lactobacillus gasseri BC9 and subsequently loaded in liposomes (LP), was evaluated for its ability to prevent the development and to eradicate the biofilm of different methicillin resistant S. aureus (MRSA) strains. BS from L. gasseri BC9 was not cytotoxic and was able to prevent formation and to eradicate the biofilm of different MRSA strains. BS loaded liposomes (BS-LP) presented a mean diameter (lower than 200 nm) suitable for topical administration and a low polydispersity index (lower than 0.2) that were maintained over time for up 28 days. Notably, BS-LP showed higher ability than free BS to inhibit S. aureus biofilm formation and eradication. BS-LP were loaded in lyophilized matrices able to quickly dissolve (dissolution time lower than 5 s) upon contact with exudate, thus allowing vesicle reconstitution. In conclusion, in this work, we demonstrated the antibiofilm activity of Lactobacillus-derived BS and BS-LP against clinically relevant MRSA strains. Furthermore, the affordable production of lyophilized matrices containing BS-LP for local prevention of cutaneous infections was established.

Microbial biosurfactants: current trends and applications in agricultural and biomedical industries

Synthetic surfactants are becoming increasingly unpopular in many applications due to previously disregarded effects on biological systems and this has led to a new focus on replacing such products with biosurfactants that are biodegradable and produced from renewal resources. Microbially derived biosurfactants have been investigated in numerous studies in areas including: increasing feed digestibility in an agricultural context, improving seed protection and fertility, plant pathogen control, antimicrobial activity, antibiofilm activity, wound healing and dermatological care, improved oral cavity care, drug delivery systems and anticancer treatments. The development of the potential of biosurfactants has been hindered somewhat by the myriad of approaches taken in their investigations, the focus on pathogens as source species and the costs associated with large-scale production. Here, we focus on various microbial sources of biosurfactants and the current trends in terms of agricultural and biomedical applications.

Biosurfactant production by yeasts from different types of soil of the South Shetland Islands (Maritime Antarctica)

AIM

To screen and identify a potential biosurfactant-producing yeast strain isolated from Antarctic soil and to evaluate the fermentation process kinetics of the most promising strain on biosurfactant production using glycerol as carbon source.

METHODS AND RESULTS

From the 68 isolated yeast strains, 11 strains were able to produce biosurfactants after Emulsification Index (E.I.) and Drop Collapse tests, reaching an E.I. higher than 10%. Strain 1_4.0 was the best producer, identified as Candida glaebosa based on molecular analysis. Yeast was cultivated in a medium composed of glycerol supplemented with yeast extract for 120 h to determine the process kinetics. The increased C/N ratio affected yeast growth and biosurfactant production. Biosurfactant release was associated with the end of exponential and beginning of the stationary growth phases. Results indicated an E.I. of 30% at the end of the fermentation.

CONCLUSIONS

The feasiability of C. glaebosa to produce biosurfactant from a low-cost medium cultivation shows a great impact on the development of bioresource in the Antarctica terrestrial environment.

SIGNIFICANCE AND IMPACT OF THE STUDY

Although the diversity of psychrophilic/psychrotolerant micro-organisms from Antarctica has been the preferred subject of study by microbiologists, terrestrial microfungal communities are scarcely investigated and literature about the biotechnological potential of such micro-organisms should cover important biomolecules in addition to cold-adapted enzymes. In the present study, for the first time, the Maritime Antarctica environment was screened as a novel source of biosurfactants produced by micro-organisms.

Inhibition of pathogenic bacterial biofilms on PDMS based implants by L. acidophilus derived biosurfactant

Background

Lactobacillus spp. predominantly shows its presence as a normal mucosal flora of the mouth and intestine. Therefore, the objective of our research is to investigate the in-vitro conditions for the prospective of medically valuable biosurfactants (BSs) derived from Lactobacillus spp. Biosurfactant (BS) obtained from Lactobacillus spp. exhibit antibiofilm and antiadhesive activity against broad range of microbes. In the present study we investigated the production, purification and properties of key components of the cell-associated-biosurfactant (CABS) from Lactobacillus acidophilus NCIM 2903.

Results

Extracted, purified, freeze-dried CABS shows reduction in surface tension (SFT) of phosphate buffer saline (PBS @pH 7.0) from 71 to 26 mN/m and had a critical micelle concentration (CMC) of 23.6 mg/mL. The CABS showed reduction in interfacial tension (IFT) against various hydrocarbons and had effective spreading capability as reflected through the decrease in contact angle (CA) on different surfaces (polydimethylsiloxane - PDMS, Teflon tape, glass surface, polystyrene film and OHP sheet). The anionic nature of CABS displayed stability at different pH and temperatures and formed stable emulsions. Thin layer chromatography (TLC) and Fourier transform infrared spectroscopy (FTIR) revealed CABS as glycolipoprotein type. The Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS-PAGE) showed presence of multiple bands in a molecular range of 14.4 to 60 kDa, with prominent bands of 45 kDa. The CABS has significant antiadhesion and antibiofilm activity against tested bacterial strains.

Conclusion

The current challenging situation is to develop methods or search for the molecules that will prevent the formations of biofilm on medical bioimplants of PDMS based materials. These findings are supportive for the use of Lactobacilli derived BS as potential antiadhesive agent on various surfaces of biomedical devices.

Interfacial Activity of Phasin PhaF from Pseudomonas putida KT2440 at Hydrophobic-Hydrophilic Biointerfaces

Phasins, the major proteins coating polyhydroxyalkanoate (PHA) granules, have been proposed as suitable biosurfactants for multiple applications because of their amphiphilic nature. In this work, we analyzed the interfacial activity of the amphiphilic α-helical phasin PhaF from Pseudomonas putida KT2440 at different hydrophobic-hydrophilic interfacial environments. The binding of PhaF to surfaces containing PHA or phospholipids, postulated as structural components of PHA granules, was confirmed in vitro using supported lipid bilayers and confocal microscopy, with polyhydroxyoctanoate- co-hexanoate P(HO- co-HHx) and Escherichia coli lipid extract as model systems. The surfactant-like capabilities of PhaF were determined by measuring changes in surface pressure in Langmuir devices. PhaF spontaneously adsorbed at the air-water interface, reducing the surface tension from 72 mN/m (water surface tension at 25 °C) to 50 mN/m. The differences in the adsorption of the protein in the presence of different phospholipid films showed a marked preference for phosphatidylglycerol species, such as 1-palmitoyl-2-oleoyl- sn-glycero-3-phosphoglycerol. The PHA-binding domain of PhaF (BioF) conserved a similar surface activity to PhaF, suggesting that it is responsible for the surfactant properties of the whole protein. These new findings not only increase our knowledge about the role of phasins in the PHA machinery but also open new outlooks for the application of these proteins as biosurfactants.

The effect of the presence of biosurfactant on the permeation of pharmaceutical compounds through silicone membrane

The permeation of ten model drugs through silicone membrane was analysed to investigate the effect of the presence of a biosurfactant obtained from corn steep liquor. The ten selected pharmaceutical compounds were chosen to include a diverse range of physicochemical properties, such as variable hydrophobicities, pKa's, molecular masses and degrees of ionisation. When compared with compound permeation alone, the additional inclusion of biosurfactant in the donor phase altered the rate and extent of permeation. It significantly enhanced permeation for five of the compounds, whereas it decreased permeation for four of the compounds and remained approximately the same for the tenth compound. These effects were observed at both biosurfactant concentrations considered, namely 0.005 mg/mL, i.e. below the critical micellar concentration (CMC) and 0.500 mg/mL, i.e. above the CMC of the biosurfactant. Upon analysing permeation change with respect to physicochemical properties of the compounds, it was determined that compounds with a relative molecular mass below 200 resulted in an increase in permeation with biosurfactant present, and those above 200 resulted in a decrease in permeation with biosurfactant present. This effect was therefore attributed to the formation of a drug-biosurfactant interaction that enhanced permeation of smaller compounds, yet retarded permeation for those with a higher molecular mass. These in vitro findings can be considered an indication of potential novel formulation options that incorporate biosurfactant to create transdermal products that have bespoke permeation profiles.

An Efficient Bioemulsifier-Producing Bacillus subtilis UCP 0146 Isolated from Mangrove Sediments

In this work, we investigated the potential of Bacillus subtilis UCP 0146 in the bioconversion of a medium containing 100% cassava flour wastewater to obtain a bioemulsifier. The evaluation of the production was carried out by the emulsification index (IE24) and the surface tension (ST). The ionic charge, stability (temperature, salinity, and pH measured by IE24 and viscosity), and ability to remove and disperse oil and textile dye were investigated. B. subtilis produced an anionic bioemulsifier in the medium containing 100% cassava wastewater under Condition 4 of the factorial design (inoculum 9% at a temperature of 35 °C and shaken at 100 rpm), and showed a surface tension of 39 mN/m, an IE24 of 95.2%, and a yield of 2.69 g·L−1. The bioemulsifier showed stability at different pH (2–8), temperatures (0–120 °C), and NaCl concentrations, a dispersion oil displacement area (ODA) test of 55.83 cm2, and a reduction of the viscosity of the burned engine oil (90.5 Cp). The bioemulsifier was able to remove petroleum (94.4%) and methylene blue azo dye (62.2%). The bioemulsifier and its synthesis from bacteria also emphasizes the role of surfactants in oil remediation.

Trehalose Lipid Biosurfactant Reduces Adhesion of Microbial Pathogens to Polystyrene and Silicone Surfaces: An Experimental and Computational Approach

Rhodococcus fascians BD8, isolated from Arctic soil, was found to produce biosurfactant when grown on n-hexadecane as the sole carbon source. The glycolipid product was identified as the trehalose lipid with a molecular mass of 848 g mol^-1. The purified biosurfactant reduced the surface tension of water from 72 to 34 mN m^-1. The critical micelle concentration of trehalose lipid was 0.140 mg mL^-1. To examine its potential for biomedical applications, the antimicrobial and antiadhesive activity of the biosurfactant was evaluated against several pathogenic microorganisms. Trehalose lipid showed antimicrobial activity against resistant pathogens. The largest antimicrobial activities of trehalose lipid were observed against Vibrio harveyi and Proteus vulgaris. The highest concentration tested (0.5 mg mL^-1) caused a partial (11-34%) inhibition of other Gram-positive and Gram-negative bacteria and 30% inhibition of Candida albicans growth. The trehalose lipid also showed significant antiadhesive properties against all of the tested microorganisms to polystyrene surface and silicone urethral catheters. The biosurfactant showed 95 and 70% antiadhesive activity against C. albicans and Escherichia coli, respectively. Finally, the role and application of trehalose lipid as an antiadhesive compound was investigated by the modification of the polystyrene and silicone surfaces. The intermolecular interaction energy calculations were performed for investigated complexes at the density functional level of theory. The results indicate that the presence of aromatic moieties can be substantial in the stabilization of trehalose lipid-surface complexes. The antimicrobial and antiadhesive activities of trehalose lipid make them promising alternatives to synthetic surfactants in a wide range of medical applications. Based on our findings, we propose that, because of its ability to inhibit microbial colonization of polystyrene and silicone surfaces, trehalose lipid can be used as a surface coating agent.

Saponins and microbial biosurfactants: Potential raw materials for the formulation of cosmetics

The cosmetic industry is currently one of the fasting growing sections of the economy in many countries. The recent tendency toward the use of cosmetics of a natural origin has driven the industry to seek alternatives to synthetic components in the formulation of products. Biosurfactants are natural compounds that have considerable potential for application in the formulation of safe, effective cosmetics as a replacement for commonly used chemical tensioactive agents. The present review provides essential information on the physicochemical and biological properties of saponins and microbial biosurfactants employed in cosmetic products, with a focus on the use of these natural compounds in shampoos, addressing the current state of research and patents involving biosurfactants for this purpose. The challenges and prospects of this cosmetic application are also discussed. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:1482-1493, 2018.

Screening, isolation and characterization of biosurfactant producing Bacillus subtilis strain ANSKLAB03

Biosurfactants are surface-active compounds produced by a wide range of microorganisms. They have both hydrophobic and hydrophilic domains and can decrease the surface tension and the interfacial tension of growth medium. Biosurfactants have different chemical structures like-lipopeptides, glycolipids, neutral lipids and fatty acids. They are biodegradable non-toxic biomolecules that show strong emulsification of hydrophobic compounds. They have the ability to form stable emulsions. The low water-solubility of these compounds restricts their availability to microorganisms. Surfactants secreted by microbes enhance the bioavailability of such hydrophobic compounds for bioremediation. Therefore, biosurfactant-enhanced solubility of pollutants has prospective applications in bioremediation. Biosurfactants are useful in a variety of industrial processes, and are also of vital importance to the microbes in adhesion, emulsification, and bioavailability, desorption and defense strategy. Therefore, it is of interest to identify biosurfuctantproducing strain of bacteria from brackish water. The microbial samples were isolated from the Chilika Lake, odisha, India and were tested for its biosurfactant property by various biochemical methods. 16S rRNA was sequenced using Sanger dideoxy sequencing method to characterize the biosurfuctant producing strain. The new Bacillus subtilis strain ANSKLAB03 isolated from 40 samples was deposited in GenBank with accession number KU523257.

Simple glycolipids of microbes: Chemistry, biological activity and metabolic engineering

Glycosylated lipids (GLs) are added-value lipid derivatives of great potential. Besides their interesting surface activities that qualify many of them to act as excellent ecological detergents, they have diverse biological activities with promising biomedical and cosmeceutical applications. Glycolipids, especially those of microbial origin, have interesting antimicrobial, anticancer, antiparasitic as well as immunomodulatory activities. Nonetheless, GLs are hardly accessing the market because of their high cost of production. We believe that experience of metabolic engineering (ME) of microbial lipids for biofuel production can now be harnessed towards a successful synthesis of microbial GLs for biomedical and other applications. This review presents chemical groups of bacterial and fungal GLs, their biological activities, their general biosynthetic pathways and an insight on ME strategies for their production.

Effect of Different Carbon Sources on Biosurfactants' Production by Three Strains of Lactobacillus spp

The potential of three indigenous bacterial strains (Lactobacillus delbrueckii N2, Lactobacillus cellobiosus TM1, and Lactobacillus plantarum G88) for the production of biosurfactants using sugar cane molasses or glycerol as substrates was investigated through emulsifying, surface tension, and antimicrobial activities. The different biosurfactants produced with molasses as substrate exhibited high surface tension reduction from 72 mN/m to values ranged from 47.50 ± 1.78 to 41.90 ± 0.79 mN/m and high emulsification index ranging from 49.89 ± 5.28 to 81.00 ± 1.14%. Whatever the Lactobacillus strain or the substrate used, the biosurfactants produced showed antimicrobial activities against Candida albicans LV1, some pathogenic and/or spoilage Gram-positive and Gram-negative bacteria. The yields of biosurfactants with molasses (2.43 ± 0.09 to 3.03 ± 0.09 g/L) or glycerol (2.32 ± 0.19 to 2.82 ± 0.05 g/L) were significantly (p < 0.05) high compared to those obtained with MRS broth as substrate (0.30 ± 0.02 to 0.51 ± 0.09 g/L). Preliminary characterization of crude biosurfactants reveals that they are mainly glycoproteins and glycolipids with molasses and glycerol as substrate, respectively. Therefore, sugar cane molasses or glycerol can effectively be used by Lactobacillus strains as low-cost substrates to increase their biosurfactants production.

Optimization and characterization of biosurfactant from Streptomyces griseoplanus NRRL-ISP5009 (MS1)

AIMS

This work aimed to study, isolate, characterize and stabilize the biosurfactant isolated from actinomycetes found in petroleum contaminated soil.

METHODS AND RESULTS

Optimized production of the biosurfactant from Streptomyces griseoplanus NRRL-ISP5009, SM1 was obtained on day 6 at 30°C, pH 7, 150 rev min^-1 , in glycerol yeast extract broth medium supplemented with cellulose, yeast extract and 1% NaCl. The stability of the biosurfactant produced was studied at different temperatures, pH and different concentrations of NaCl. The produced biosurfactant was extracted and purified.

CONCLUSION

Streptomyces griseoplanus NRRL-ISP5009, SM1 isolated from oil contaminated soil produced a biosurfactant exhibiting emulsification activity. The produced biosurfactant is a mixture of carbohydrate, lipid and protein. It has promising characteristics, including a higher stability at alkaline pH than at acidic pH, a salinity of 1-3% and stable in the temperature range from 0 and 100°C. Also, the potential antimicrobial activity of the purified biosurfactant was recorded.

SIGNIFICANCE AND IMPACT OF THE STUDY

The research was focused on the isolation of a novel source of biosurfactants that have great importance in the manufacture of food, detergent, pharmaceutical and cosmetics.

Advances in applications of rhamnolipids biosurfactant in environmental remediation: A review

The objective of this review is to provide a comprehensive overview of the advances in the applications of rhamnolipids biosurfactants in soil and ground water remediation for removal of petroleum hydrocarbon and heavy metal contaminants. The properties of rhamnolipids associated with the contaminant removal, that is, solubilization, emulsification, dispersion, foaming, wetting, complexation, and the ability to modify bacterial cell surface properties, were reviewed in the first place. Then current remediation technologies with integration of rhamnolipid were summarized, and the effects and mechanisms for rhamnolipid to facilitate contaminant removal for these technologies were discussed. Finally rhamnolipid-based methods for remediation of the sites co-contaminated by petroleum hydrocarbons and heavy metals were presented and discussed. The review is expected to enhance our understanding on environmental aspects of rhamnolipid and provide some important information to guide the extending use of this fascinating chemical in remediation applications.

Variants of lipopeptides and glycolipids produced by Bacillus amyloliquefaciens and Pseudomonas aeruginosa cultured in different carbon substrates

The quantitative and qualitative effect of water immiscible and miscible carbon-rich substrates on the production of biosurfactants, surfactin and rhamnolipids, by Bacillus amyloliquefaciens ST34 and Pseudomonas aeruginosa ST5, respectively, was analysed. A small-scale high throughput 96 deep-well micro-culture method was utilised to cultivate the two strains in mineral salt medium (MSM) supplemented with the water miscible (glucose, glycerol, fructose and sucrose) and water immiscible carbon sources (diesel, kerosene and sunflower oil) under the same growth conditions. The biosurfactants produced by the two strains were isolated by acid precipitation followed by an organic solvent extraction. Ultra-performance liquid chromatography coupled to electrospray ionisation mass spectrometry was utilised to analyse yields and characterise the biosurfactant variants. For B. amyloliquefaciens ST34, maximum surfactin production was observed in the MSM supplemented with fructose (28 mg L⁻¹). In addition, four surfactin analogues were produced by ST34 using the different substrates, however, the C₁₃–C₁₅ surfactins were dominant in all extracts. For P. aeruginosa ST5, maximum rhamnolipid production was observed in the MSM supplemented with glucose (307 mg L⁻¹). In addition, six rhamnolipid congeners were produced by ST5 using different substrates, however, Rha–Rha–C₁₀–C₁₀ and Rha–C₁₀–C₁₀ were the most abundant in all extracts. This study highlights that the carbon sources utilised influences the yield and analogues/congeners of surfactin and rhamnolipids produced by B. amyloliquefaciens and P. aeruginosa, respectively. Additionally, glucose and fructose were suitable substrates for rhamnolipid and surfactin, produced by P. aeruginosa ST5 and B. amyloliquefaciens ST34, which can be exploited for bioremediation or as antimicrobial agents.

Bioactivity of glycolipopeptide cell-bound biosurfactants against skin pathogens

The antimicrobial and anti-adhesive activities of the cell-bound biosurfactants, produced by Lactobacillus pentosus (PEB), characterized as glycolipopeptide macromolecules, were evaluated against several microorganisms present in the skin microflora, envisaging its potential use as a "natural" ingredient in cosmetic and personal care formulations. Their performance was compared with another cell-bound biosurfactants also characterized as glycolipopeptides produced by Lactobacillus paracasei (PAB). At concentrations of 50mg/mL, the PEB showed an important antimicrobial activity against Pseudomonas aeruginosa (85% when extracted with phosphate buffer (PB) and 100% when extracted with phosphate buffer saline (PBS)), Streptococcus agalactiae (100% for both extracts), Staphylococcus aureus (67% when extracted with PBS and 100% when extracted with PB), Escherichia coli (72% when extracted with PB and 89% when extracted with PBS), Streptococcus pyogenes (about 85% for both extracts) and Candida albicans (around 70% for both extracts), comparable with that obtained for the PAB. However, at lower concentrations the PAB exhibited in general higher antimicrobial activities. Biosurfactants produced by both microorganisms also showed significant anti-adhesive properties against all the microorganisms under study, except for E. coli and C. albicans (less than 30%). Overall, these cell-bound biosurfactants could be used as potential antimicrobial and anti-adhesive agents in cosmetic and pharmaceutical formulations.

Biosurfactants produced by Scheffersomyces stipitis cultured in sugarcane bagasse hydrolysate as new green larvicides for the control of Aedes aegypti, a vector of neglected tropical diseases

Biosurfactants are microbial metabolites with possible applications in various industrial sectors that are considered ecofriendly molecules. In recent years, some studies identified these compounds as alternatives for the elimination of vectors of tropical diseases, such as Aedes aegypti. The major bottlenecks of biosurfactant industrial production have been the use of conventional raw materials that increase production costs as well as opportunistic or pathogenic bacteria, which restrict the application of these biomolecules. The present study shows the potential of hemicellulosic sugarcane bagasse hydrolysate as a raw material for the production of a crystalline glycolipidic BS by Scheffersomyces stipitis NRRL Y-7124, which resulted in an emulsifying index (EI24) of 70 ± 3.4% and a superficial tension of 52 ± 2.9 mN.m-1. Additionally, a possible new application of these compounds as biolarvicides, mainly against A. aegypti, was evaluated. At a concentration of 800 mg.L-1, the produced biosurfactant caused destruction to the larval exoskeletons 12 h after application and presented an letal concentration (LC50) of 660 mg.L-1. Thus, a new alternative for biosurfactant production using vegetal biomass as raw material within the concept of biorefineries was proposed, and the potential of the crystalline glycolipidic biosurfactant in larvicidal formulations against neglected tropical disease vectors was demonstrated.

Anticancer Activities of Surfactin and Potential Application of Nanotechnology Assisted Surfactin Delivery

Surfactin, a cyclic lipopeptide biosurfactant produced by various strains of Bacillus genus, has been shown to induce cytotoxicity against many cancer types, such as Ehrlich ascites, breast and colon cancers, leukemia and hepatoma. Surfactin treatment can inhibit cancer progression by growth inhibition, cell cycle arrest, apoptosis, and metastasis arrest. Owing to the potent effect of surfactin on cancer cells, numerous studies have recently investigated the mechanisms that underlie its anticancer activity. The amphiphilic nature of surfactin allows its easy incorporation nano-formulations, such as polymeric nanoparticles, micelles, microemulsions, liposomes, to name a few. The use of nano-formulations offers the advantage of optimizing surfactin delivery for an improved anticancer therapy. This review focuses on the current knowledge of surfactin properties and biosynthesis; anticancer activity against different cancer models and the underlying mechanisms involved; as well as the potential application of nano-formulations for optimal surfactin delivery.

Lipase and biosurfactant from Ochrobactrum intermedium strain MZV101 isolated by washing powder for detergent application

Background

Alkaline thermostable lipase and biosurfactant producing bacteria are very interested at detergent applications, not only because of their eco-friendly characterize, but alsoproduction lipase and biosurfactant by using cheap materials. Ochrobactrum intermedium strain MZV101 was isolated as washing powder resistant, alkaline thermostable lipase and biosurfactant producing bacterium in order to use at detergent applications.

Methods

O. intermedium strain MZV101 produces was lipase and biosurfactant in the same media with pH 10 and temperature of 60 °C. Washing test and some detergent compatibility character of lipase enzyme and biosurfactant were assayed. The antimicrobial activity evaluated against various bacteria and fungi.

Results

Lipase and biosurfactant produced by O. intermedium strain MZV101 exhibited high stability at pH 10–13 and temperature of 70–90 °C, biosurfactant exhibits good stability at pH 9–13 and thermostability in all range. Both lipase and biosurfactant were found to be stable in the presence of different metal ions, detergents and organic solvents. The lipase enzyme extracted using isopropanol with yield of 69.2% and biosurfactant with ethanol emulsification index value of 70.99% and yield of 9.32 (g/l). The single band protein after through from G-50 Sephadex column on SDS-PAGE was calculated to be 99.42 kDa. Biosurfactant O. intermedium strain MZV101 exhibited good antimicrobial activity against Gram-negative bacteria and against various bacterial pathogens. Based upon washing test biosurfactant and lipase O. intermedium strain MZV101considered being strong oil removal.

Conclusion

The results of this study indicate that isolated lipase and biosurfactant with strong oil removal, antimicrobial activity and good stability could be useful for detergent applications.

Graphical abstract

Statistical Methodologies for the Optimization of Lipase and Biosurfactant by Ochrobactrum intermedium Strain MZV101 in an Identical Medium for Detergent Applications

The Plackett-Burman design and the Box-Behnken design, statistical methodologies, were employed for the optimization lipase and biosurfactant production by Ochrobactrum intermedium strain MZV101 in an identical broth medium for detergent applications. Environmental factor pH determined to be most mutual significant variables on production. A high concentration of molasses at high temperature and pH has a negative effect on lipase and biosurfactant production by O. intermedium strain MZV101. The chosen mathematical method of medium optimization was sufficient for improving the industrial production of lipase and biosurfactant by bacteria, which were respectively increased 3.46- and 1.89-fold. The duration of maximum production became 24 h shorter, so it was fast and cost-saving. In conclusion, lipase and biosurfactant production by O. intermedium strain MZV101 in an identical culture medium at pH 10.5-11 and 50-60 °C, with 1 g/L of molasses, seemed to be economical, fast, and effective for the enhancement of yield percentage for use in detergent applications.

Biosurfactants during in situ bioremediation: factors that influence the production and challenges in evalution

Research on the influence of biosurfactants on the efficiency of in situ bioremediation of contaminated soil is continuously growing. Despite the constant progress in understanding the mechanisms involved in the effects of biosurfactants, there are still many factors that are not sufficiently elucidated. There is a lack of research on autochthonous or exogenous microbial metabolism when biostimulation or bioaugmentation is carried out to produce biosurfactants at contaminated sites. In addition, studies on the application of techniques that measure the biosurfactants produced in situ are needed. This is important because, although the positive influence of biosurfactants is often reported, there are also studies where no effect or negative effects have been observed. This review aimed to examine some studies on factors that can improve the production of biosurfactants in soils during in situ bioremediation. Moreover, this work reviews the methodologies that can be used for measuring the production of these biocomposts. We reviewed studies on the potential of biosurfactants to improve the bioremediation of hydrocarbons, as well as the limitations of methods for the production of these biomolecules by microorganisms in soil.

The yeast-like fungus Aureobasidium thailandense LB01 produces a new biosurfactant using olive oil mill wastewater as an inducer

In this study, the biosurfactant production by an Aureobasidium thailandense LB01 was reported for the first time. Different agro-industrial by-products (corn steep liquor, sugarcane molasses, and olive oil mill wastewater) were evaluated as alternative low-cost substrates. The composition of the culture medium was optimized through response surface methodology. The highest biosurfactant production (139±16mg/L) was achieved using a culture medium containing yeast extract (2g/L); olive oil mill wastewater (1.5%, w/w); glucose (6g/L) and KH₂PO₄ (1g/L) after 48h of fermentation. The partially purified biosurfactant exhibited a critical micelle concentration of 550mg/L, reducing the surface tension of water up to 31.2mN/m. Its molecular structure was found to be similar to a lauric acid ester. The biosurfactant exhibited a better performance than the chemical surfactant sodium dodecyl sulfate (SDS) in oil dispersion assays, thus suggesting its potential application in bioremediation.

Biological activity of lipopeptides from Bacillus

The lipopeptides of Bacillus are small metabolites that contain a cyclic structure formed by 7-10 amino acids (including 2-4 D-amino acids) and a beta-hydroxy fatty acid with 13-19 C atoms. These lipopeptides exhibit a variety of biological activities, including interactions with biofilms, and anti-fungal, anti-inflammatory, anti-tumor, anti-virus, and anti-platelet properties. The multiple activities of lipopeptides have stimulated significant interest in the exploitation of these lipopeptides for use as antibiotics, feed additives, anti-tumor agents, urgent thrombolytic therapeutic agents, and drug delivery systems. Understanding the natural function of these structurally diverse lipopeptides in Bacillus provides insight into microbial regulatory programs and is required for efficient development of more effective products. Currently, there is still insufficient knowledge of the direct target of these lipopeptides, and continued efforts are needed to enhance their biosynthesis efficiency for industrial applications.

Evaluation of Bacillus subtilis SPB1 biosurfactant effects on hyperglycemia, angiotensin I-converting enzyme (ACE) activity and kidney function in rats fed on high-fat-high-fructose diet

This study investigated the protective and the curative effects of Bacillus subtilis SPB1 crude lipopeptide biosurfactant in alleviating induced obesity complications in rats fed on high-fat-high-fructose diet (HFFD). Male Wistar rats were divided into five groups with the following treatment schedule: normal diet-fed rats (CD), HFFD-fed rats, HFFD-fed rats supplemented with SPB1 biosurfactant from the first day of the experiment (HFFD + Bios1), rats fed on HFFD receiving standard drug (HFFD + Torva), or SPB1 biosurfactant (HFFD + Bios2) during the last 4 weeks of the study. HFFD induced hyperglycemia, manifested by a significant (p < 0.001) increase (20%) in the levels of glucose and α-amylase activity in the plasma, when compared with CD. The administration of SPB1 biosurfactant to rats fed on HFFD reverted back normal blood glucose and α-amylase activity levels. Also, the findings clearly showed that acute oral administration of SPB1 biosurfactant reduced significantly (34%) the peak of blood glucose concentration 60 min after glucose administration, as compared with untreated rats fed on HFFD. Furthermore, renal dysfunction indices such as creatinine and urea as well as the level of angiotensin I-converting enzyme (ACE) exhibited remarkable increases in serum of rats fed on HFFD by 28.35%, 46%, and 92%,. Interestingly, SPB1 lipopeptides treatments decreased the creatinine and urea levels significantly (p < 0.001) near normal values, as compared with that of the HFFD group, and also showed an improvement of the kidney cortex architecture. Moreover, SPB1 biosurfactant displayed a potent inhibition of ACE activity in vitro (CI₅₀ value=1.37 mg/mL) as well as in vivo in obese rats by 42% and 27.25% with HFFD + Bios1 and HFFD + Bios2 treatments, respectively, and comparatively with the HFFD group. Besides, SPB1 lipopeptides treatments improved some of serum electrolytes such as Na⁺, K⁺, Ca²⁺, and Mg²⁺. The results showed that SPB1 lipopeptide biosurfactant presented useful hypoglycemic and antihypertensive properties, and was able to alleviate renal lipid deposition in rats fed on a hypercaloric diet.

Direct quantification of lipopeptide biosurfactants in biological samples via HPLC and UPLC-MS requires sample modification with an organic solvent

The rapid and accurate quantification of biosurfactants in biological samples is challenging. In contrast to the orcinol method for rhamnolipids, no simple biochemical method is available for the rapid quantification of lipopeptides. Various liquid chromatography (LC) methods are promising tools for relatively fast and exact quantification of lipopeptides. Here, we report strategies for the quantification of the lipopeptides pseudofactin and surfactin in bacterial cultures using different high- (HPLC) and ultra-performance liquid chromatography (UPLC) systems. We tested three strategies for sample pretreatment prior to LC analysis. In direct analysis (DA), bacterial cultures were injected directly and analyzed via LC. As a modification, we diluted the samples with methanol and detected an increase in lipopeptide recovery in the presence of methanol. Therefore, we suggest this simple modification as a tool for increasing the accuracy of LC methods. We also tested freeze-drying followed by solvent extraction (FDSE) as an alternative for the analysis of “heavy” samples. In FDSE, the bacterial cultures were freeze-dried, and the resulting powder was extracted with different solvents. Then, the organic extracts were analyzed via LC. Here, we determined the influence of the extracting solvent on lipopeptide recovery. HPLC methods allowed us to quantify pseudofactin and surfactin with run times of 15 and 20 min per sample, respectively, whereas UPLC quantification was as fast as 4 and 5.5 min per sample, respectively. Our methods provide highly accurate measurements and high recovery levels for lipopeptides. At the same time, UPLC-MS provides the possibility to identify lipopeptides and their structural isoforms.

Surfactin-loaded polyvinyl alcohol (PVA) nanofibers alters adhesion of Listeria monocytogenes to polystyrene

Surfactin-loaded polyvinyl alcohol (PVA) nanofibers were spun using gravity electrospinning. Scanning electron microscopy (SEM) images showed that nanofibers spun with surfactin are free from bead formation and uniform in diameter. The average nanofiber diameters were decreased (273±39nm, 259±39nm and 217±33nm) with increasing levels of surfactin (0.5, 1.0 and 1.5%, w/v) into PVA (10%, w/v). The 10% (w/v) PVA had average fiber diameter of 303±33nm. Atomic force microscopy (AFM) analysis showed that fibers spun with surfactin are not smooth as PVA fibers. The surface average roughness (S_a) estimated for surfactin loaded nanofibers (0.5%: 19.0nm, 1.0%: 20.4nm and 1.5%: 20.7nm) was higher as compared with PVA (10%:15.8nm). Scanning transmission electron microscopy (STEM) showed no matrix differences between PVA and surfactin-loaded PVA nanofibers. Fourier transform infrared (FTIR) microscopy revealed uniform distribution of surfactin in PVA. Based on differential scanning calorimetry (DSC) analyses, surfactin decreased the crystallinity of PVA during spinning. No antimicrobial activity was detected against methicillin-resistant Staphylococcus aureus (MRSA) strain Xen 30, Listeria monocytogenes EDGe, Escherichia coli Xen 14, and Pseudomonas aeruginosa PA01. However, the adhesion of L. monocytogenes to polystyrene in presence of surfactin-loaded nanofibers decreased significantly (OD₅₉₅: 0.012±0.001) as compared with control (OD₅₉₅: 0.022±0.002), suggesting that these nanofibers may be used in wound dressings or in the coating of prosthetic devices to prevent biofilm formation and secondary infections.

Therapeutic implication of 'Iturin A' for targeting MD-2/TLR4 complex to overcome angiogenesis and invasion

Tumor angiogenesis and invasion are deregulated biological processes that drive multistage transformation of tumors from a benign to a life-threatening malignant state activating multiple signaling pathways including MD-2/TLR4/NF-κB. Development of potential inhibitors of this signaling is emerging area for discovery of novel cancer therapeutics. In the current investigation, we identified Iturin A (A lipopeptide molecule from Bacillus megaterium) as a potent inhibitor of angiogenesis and cancer invasion by various in vitro and in vivo methods. Iturin A was found to suppress VEGF, a powerful inducer of angiogenesis and key player in tumor invasion, as confirmed by ELISA, western blot and real time PCR. Iturin A inhibited endothelial tube arrangement, blood capillary formation, endothelial sprouting and vascular growth inside the matrigel. In addition, Iturin A inhibited MMP-2/9 expression in MDA-MB-231 and HUVEC cells. Cancer invasion, migration and colony forming ability were significantly hampered by Iturin A. Expressions of MD-2/TLR4 and its downstream MyD88, IKK-α and NF-κB were also reduced in treated MDA-MB-231 and HUVEC cells. Western blot and immunofluorescence study showed that nuclear accumulation of NF-κB was hampered by Iturin A. MD-2 siRNA or plasmid further confirmed the efficacy of Iturin A by suppressing MD-2/TLR4 signaling pathway. The in silico docking study showed that the Iturin A interacted well with the MD-2 in MD-2/TLR4 receptor complex. Conclusively, inhibition of MD-2/TLR4 complex with Iturin A offered strategic advancement in cancer therapy.

Biosurfactants in cosmetic formulations: trends and challenges

Cosmetic products play an essential role in everyone's life. People everyday use a large variety of cosmetic products such as soap, shampoo, toothpaste, deodorant, skin care, perfume, make-up, among others. The cosmetic industry encompasses several environmental, social and economic impacts that are being addressed through the search for more efficient manufacturing techniques, the reduction of waste and emissions and the promotion of personal hygiene, contributing to an improvement of public health and at the same time providing employment opportunities. The current trend among consumers is the pursuit for natural ingredients in cosmetic products, as many of these products exhibit equal, better or additional benefits in comparison with the chemical-based products. In this sense, biosurfactants are natural compounds with great potential in the formulation of cosmetic products given by their biodegradability and impact in health. Indeed, many of these biosurfactants could exhibit a "prebiotic" character. This review covers the current state-of-the-art of biosurfactant research for cosmetic purposes and further discusses the future challenges for cosmetic applications.

Influence of micelle formation on the adsorption capacity of a biosurfactant extracted from corn on dyed hair

Biosurfactants obtained from corn steep liquor were applied to dyed hair and showed good adsorption while maintaining the dyed hair structure in a good state.

Development of a group contribution method for estimating free energy of peptides in a dodecane-water system via molecular dynamic simulations

Background

Calculation of the Gibbs free energy changes of biological molecules at the oil-water interface is commonly performed with Molecular Dynamics simulations (MD). It is a process that could be performed repeatedly in order to find some molecules of high stability in this medium.

Here, an alternative method of calculation has been proposed: a group contribution method (GCM) for peptides based on MD of the twenty classic amino acids to obtain free energy change during the insertion of any peptide chain in water-dodecane interfaces. Multiple MD of the twenty classic amino acids located at the interface of rectangular simulation boxes with a dodecane-water medium were performed.

Results

A GCM to calculate the free energy of entire peptides is then proposed. The method uses the summation of the Gibbs free energy of each amino acid adjusted in function of its presence or absence in the chain as well as its hydrophobic characteristics.

Conclusion

Validation of the equation was performed with twenty-one peptides all simulated using MD in dodecane-water rectangular boxes in previous work, obtaining an average relative error of 16%.

Electronic supplementary material

The online version of this article (doi:10.1186/s12859-016-1399-5) contains supplementary material, which is available to authorized users.