Seeking faster, alternative methods for glycolipid biosurfactant characterization and purification.

Biosurfactants have been investigated as potential alternatives for synthetic surfactants in several areas, for example, in environmental and pharmaceutical fields. In that regard, extensive research has been carried out with sophorolipids and rhamnolipids that also present various biological properties with therapeutic significance. These biosurfactants are obtained as complex mixtures of slightly different molecules, and thus when studying these microbial glycolipids, the ability to identify and purify the produced compounds is of extreme importance. This study aimed to develop improved methodologies for the identification, separation, and purification of sophorolipids and rhamnolipids. Therefore, an ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was modified to ensure faster characterization of both sophorolipids and rhamnolipids, enabling the identification and fragmentation pattern description of 10 and 13 congeners, respectively. The separation and purification of these biosurfactants was achieved with novel reversed-phase solid-phase extraction methods guaranteeing the isolation of different glycolipids, including those considered for their significant biological activity (e.g. antimicrobial, anticancer). It was possible to isolate sophorolipids and rhamnolipids with purity of 94% and 99%, respectively. The methods presented herein can be easily implemented and are expected to make purification of these biosurfactants easier, facilitating the study of their individual properties in further works.

Isolation and purification of glycoglycerolipids to induce apoptosis in breast cancer cells.

Monogalactosyldiacylglycerol (MGDG) is the most abundant type of glycoglycerolipid found in the plant cell membrane and mostly in the chloroplast thylakoid membrane. The amphiphilic nature of MGDG is attractive in pharmaceutical fields for interaction with other biological molecules and hence exerting therapeutic anti-cancer, anti-viral, and anti-inflammatory activities. In this study, we investigated the therapeutic efficacy of cyanobacteria derived MGDG to inhibit breast cancer cell growth. MGDG was extracted from a cyanobacteria Synechocystis sp. PCC 6803 followed by a subsequent fractionation by column chromatographic technique. The purity and molecular structure of MGDG were analyzed by nuclear magnetic resonance (NMR) spectroscopy analysis. The presence of MGDG in the extracted fraction was further confirmed and quantified by high-performance liquid chromatography (HPLC). The anti-proliferation activity of the extracted MGDG molecule was tested against BT-474 and MDA-MB-231 breast cancer cell lines. The in vitro study showed that MGDG extracted from Synechocystis sp. PCC 6803 induced apoptosis in (70 ± 8) % of BT-474 (p < 0.001) and (58 ± 5) % of MDA-MB-231 cells (p < 0.001) using ~ 60 and 200 ng/ml of concentrations, respectively. The half-maximal inhibitory concentration, IC50 of MGDG extracted from Synechocystis sp. PCC 6803 were (27.2 ± 7.6) and (150 ± 70) ng/ml in BT-474 and MDA-MB-231 cell lines, respectively. Quantification of caspase-3/7 activity using flow cytometry showed (3.0 ± 0.4) and (2.1 ± 0.04)-fold (p < 0.001) higher protein expressions in the MGDG treated BT-474 and MDA-MB-231 cells, respectively than untreated controls conferring to the caspase-dependent apoptosis. The MGDG did not show any significant cytotoxic side effects in human dermal fibroblasts cells. A commercially available MGDG control did not induce any apoptotic cell death in cancer cells substantiating the potential of the MGDG extracted from Synechocystis sp. PCC 6803 for the treatment of breast cancer cells through the apoptosis-mediated pathway.

Neutral Lipids, Glycolipids, and Phospholipids, Isolated from Sandfish (Arctoscopus japonicus) Eggs, Exhibit Anti-Inflammatory Activity in LPS-Stimulated RAW264.7 Cells through NF-κB and MAPKs Pathways.

Total lipids were extracted from sandfish (Arctoscopus japonicus), and then they were separated into the following three lipid fractions: neutral lipids, glycolipids, and phospholipids. In this study, we analyzed the lipid fractions of A. japonicus eggs and we determined their anti-inflammatory activity in RAW264.7 macrophage cells. In these three lipid-fractions, the main fatty acids were as follows: palmitic acid (16:0), oleic acid (18:1n-9), docosahexaenoic acid (DHA, 22:6n-3), and eicosapentaenoic acid (EPA, 20:5n-3). Among the lipid fractions, phospholipids showed the highest concentration of DHA and EPA (21.70 ± 1.92 and 18.96 ± 1.27, respectively). The three lipid fractions of A. japonicus significantly suppressed the production of NO in macrophages. Moreover, they also significantly inhibited the expression of iNOS, COX-2, IL-6, IL-1ß, and TNF-α, in a dose-dependent manner. Furthermore, the lipid fractions of A. japonicus suppressed the nuclear translocation of NF-κB p65 subunits in a dose-dependent manner. In addition, they attenuated the activation of MAPKs (p38, ERK1/2, and JNK) phosphorylation in LPS-stimulated RAW264.7 cells. These results indicate that all the lipid fractions of A. japonicus exert anti-inflammatory activity by suppressing the activation of NF-κB and MAPK pathways. Therefore, the lipid fractions of A. japonicus might be potentially used as anti-inflammatory agents.

Lipid Composition of Liposomal Membrane Largely Affects Its Transport and Uptake through Small Intestinal Epithelial Cell Models.

Lipid composition of liposomal bilayer should alter the cell response for permeability, transport, and uptake in small intestine. This work was done to investigate the transport and uptake of liposomes composed of docosahexaenoic acid-enriched phosphatidylcholine (PtdCho), phosphatidylserine (PtdSer), and sulfoquinovosyl diacylglycerol (SQDG) derived from marine products on multilamellar vesicles (MLV) in small intestinal epithelial cell models. The results showed that addition of PtdSer and SQDG as liposomal bilayer could improve the efficiency entrapment of liposomes. The liposomes containing PtdSer showed higher transport and uptake through both Caco-2 cell and M cell monolayers as compared to PtdCho-MLV. SQDG-containing liposomes exhibited only higher transport through M cell monolayer, while its uptake effect was higher both in Caco-2 cell and M cell monolayers. The results of experiments done with endocytosis inhibitors indicated that PtdCho-MLV must be transported via macropinocytosis and uptaken by phagocytosis in M cell monolayer model. PtdCho/PtdSer-MLV and PtdCho/SQDG-MLV might be transported and uptaken through M cell monolayer by phagocytosis. The result also indicated that PtdCho/SQDG-MLV could open the tight junction of small intestinal epithelial cell monolayers. Furthermore, our findings demonstrated that the surface status of cholesterol-containing liposomes were smooth, but they did not affect their transport and uptake through Caco-2 cell and M cell monolayers.

Diagnostic strategy for females suspected of Fabry disease.

A total of 11 948 females suspicious of Fabry disease were tested by a combined biochemical and genetic approach. The enzyme activity, together with the concentration of lyso-GL-3 (lyso-Gb3) biomarker in dried blood spots (DBS), substantially improved the diagnostic detection of Fabry disease in females compared to the enzyme activity alone. Abnormal values for both were highly suspicious of Fabry disease (97% positive predictive value [PPV], similar to PPV in males). In cases with one abnormal biochemical value, elevated lyso-GL-3 is a far more important indicator than low enzyme activity (39% PPV vs 6% PPV). Cases with clearly negative results for both biochemical parameters are unlikely to have Fabry disease, even in clinically highly suspicious cases.

Antibacterial Activity of Sophorolipids from Candida bombicola Against Human Pathogens

Abstract Sophorolipids are glycolipids that have natural antimicrobial properties and present great potential in the pharmaceutical field. The present study aimed to produce sophorolipids from Candida bombicola using a chicken fat-based medium and evaluate the antimicrobial activity against Gram-negative (Proteus mirabilis, Escherichia coli, Salmonella enterica subsp. enterica) and Gram-positive bacteria (Enterococcus faecium, Staphylococcus aureus and Streptococcus mutans). The production of sophorolipids reached 27.86 g L-1. Based on the structural characterization, 73.55% of the sophorolipids present a mixture of acidic monoacetylated C18:2 and lactonic diacetylated C16:0, and 26.45% were present in the diacetylated C18:1 lactonic form. Bacteria submitted to sophorolipid exposure showed a reduction in viability at doses of 500 μg mL-1 and 2,000 μg mL-1 against Gram-positive and Gram-negative bacteria, respectively. These results suggest that sophorolipids produced in chicken fat medium may be used as antimicrobial agents to prevent or eliminate contamination by different pathogens.

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.

Dokdolipids A-C, Hydroxylated Rhamnolipids from the Marine-Derived Actinomycete Actinoalloteichus hymeniacidonis.

Three new hydroxylated rhamnolipids, dokdolipids A-C (1-3) were obtained from the marine actinomycete Actinoalloteichus hymeniacidonis, which was isolated from a sediment sample collected off the coasts of Dokdo island, Republic of Korea. The structures of the isolated compounds were elucidated on the basis of 1D and 2D NMR and mass spectrometric data analyses. Their absolute configurations were assigned using the modified Mosher's method and specific rotation values, as well as acid hydrolysis, chemical derivatizations and subsequent HPLC analysis to determine the configuration of the sugar moieties. All new compounds were evaluated for their cytotoxicity against six cancer cell lines, HCT-15, NUGC-3, NCI-H23, ACHN, PC-3 and MDA-MB-231. Compounds 1-3 displayed moderate cytotoxicity against all the cell lines tested with IC50 values ranging from 13.7-41.5 µM.

Effects of Glycolipid Rhodococcus Biosurfactant on Innate and Adaptive Immunity Parameters In Vivo.

The glycolipid biosurfactant complex from actinobacterium Rhodococcus ruber IEGM 231 inhibits the innate and adaptive immunity parameters after intraperitoneal and intramuscular injection. Marked suppression of antibody production, bactericidal potential, and production of proinflammatory cytokines by peritoneal macrophages, detected in vivo, do not agree with the previously detected immunostimulatory activity of biosurfactants towards the immunocompetent cell cultures; this fact indicates an important role of the cell environment in the formation of immune response under the effect of bacterial glycolipids.

Modern separation techniques coupled to high performance mass spectrometry for glycolipid analysis.

Glycolipids (GLs), involved in biological processes and pathologies, such as viral, neurodegenerative and oncogenic transformations are in the focus of research related to method development for structural analysis. This review highlights modern separation techniques coupled to mass spectrometry (MS) for the investigation of GLs from various biological matrices. First section is dedicated to methods, which, although provide the separation in a non-liquid phase, are able to supply important data on the composition of complex mixtures. While classical thin layer chromatography (TLC) is useful for MS analyses of the fractionated samples, ultramodern ion mobility (IMS) characterized by high reproducibility facilitates to discover minor species and to apply low sample amounts, in addition to providing conformational separation with isomer discrimination. Second section highlights the advantages, applications and limitations of liquid-based separation techniques such as high performance liquid chromatography (HPLC) and hydrophilic interaction liquid chromatography (HILIC) in direct or indirect coupling to MS for glycolipidomics surveys. The on- and off-line capillary electrophoresis (CE) MS, offering a remarkable separation efficiency of GLs is also presented and critically assessed from the technical and application perspective in the final part of the review.

Oil Characterization and Lipids Class Composition of Pomegranate Seeds.

This study aims to investigate the physicochemical characteristics, phenolics content, and oil composition of pomegranate oil seeds (PSO). Quality indices, pigments, phenolics content, and antioxidant activity were determined. PSO was fractioned into polar lipids: glycolipids (GL) and phospholipids (PL). Sterols profile and fatty acids composition of total lipids (TL), GL, and PL were determined by GC/FID. The free acidity, the peroxide value, and the specific extinction coefficients were, respectively, 1.69%, 3.42 in milliequivalents of active oxygen per kilogram of oil, 4.15, and 3.95. PSO is rich in phenols (93.42 mg/Kg) but poor in pigments. The sterols markers were ß-sitosterol (77.94%), Δ5-avenasterol (7.45%), and campesterol (6.35%). Oil content was 12.2%, wherein 23.9% were GL and 24.35% were PL. TL were rich in unsaturated fatty acids (63.17%), while saturated fatty acids were more present in PL and GL (71.97% and 66.29%, resp.). Conjugated fatty acids were about 13.30%, 2.03%, and 4.91%, respectively, in TL, PL, and GL. The cis/trans ratio of TL, PL, and GL was, respectively, 49.82%, 42.91%, and 27.39%. Monounsaturated fatty acids were more bound in PL, whereas polyunsaturated fatty acids were more bound in GL. PSO is a good source of essential fatty acids, phenolics compounds, phytosterols, and lipid-soluble fractions.

Sulfated archaeal glycolipid archaeosomes as a safe and effective vaccine adjuvant for induction of cell-mediated immunity.

Archaeosomes are liposomal vesicles composed of ether glycerolipids unique to the domain of Archaea. Unlike conventional ester-linked liposomes, archaeosomes exhibit high stability and possess strong adjuvant and immunostimulatory properties making them an attractive vaccine delivery vehicle. Traditionally comprised of total polar lipids (TPL) or semi-synthetic phospho-glycerolipids of ether-linked isoprenoid phytanyl cores with varied glycol- and amino-head groups, archaeosomes can induce robust and long-lasting humoral and cell-mediated immune responses against antigenic cargo and provide protection in murine models of infectious disease and cancer. However, traditional TPL archaeosome formulations are relatively complex comprising several lipid species. Semi-synthetic archaeosomes tested previously contain a combination of several phospho-glycolipids (negative and neutral charged) to produce a stable, uniform-sized liposome formulation. Moreover, they involve many synthetic steps to arrive at the final desired glycolipid composition. Herein, we present a novel adjuvant formulation comprising a sulfated saccharide group covalently linked to the free sn-1 hydroxyl backbone of an archaeal core lipid (sulfated S-lactosylarchaeol, SLA). SLA individually or mixed with uncharged glyolipid (lactosylarchaeol, LA) constituted efficacious carrier vesicles for entrapped antigens (ovalbumin or melanoma associated tyrosinase-related protein 2 [TRP-2]) and induction of strong cell-mediated responses in mice and protection against subsequent B16 melanoma tumor challenge. Thus, semi-synthetic sulfated glycolipid archaeosomes represent a new class of adjuvants that will potentially ease manufacturing and scale-up, while retaining immunostimulatory activity.

Toll-Like Receptor 2 and Mincle Cooperatively Sense Corynebacterial Cell Wall Glycolipids.

Nontoxigenic Corynebacterium diphtheriae and Corynebacterium ulcerans cause invasive disease in humans and animals. Host sensing of corynebacteria is largely uncharacterized, albeit the recognition of lipoglycans by Toll-like receptor 2 (TLR2) appears to be important for macrophage activation by corynebacteria. The members of the order Corynebacterineae (e.g., mycobacteria, nocardia, and rhodococci) share a glycolipid-rich cell wall dominated by mycolic acids (termed corynomycolic acids in corynebacteria). The mycolic acid-containing cord factor of mycobacteria, trehalose dimycolate, activates the C-type lectin receptor (CLR) Mincle. Here, we show that glycolipid extracts from the cell walls of several pathogenic and nonpathogenic Corynebacterium strains directly bound to recombinant Mincle in vitro Macrophages deficient in Mincle or its adapter protein Fc receptor gamma chain (FcRγ) produced severely reduced amounts of granulocyte colony-stimulating factor (G-CSF) and of nitric oxide (NO) upon challenge with corynebacterial glycolipids. Consistently, cell wall extracts of a particular C. diphtheriae strain (DSM43989) lacking mycolic acid esters neither bound Mincle nor activated macrophages. Furthermore, TLR2 but not TLR4 was critical for sensing of cell wall extracts and whole corynebacteria. The upregulation of Mincle expression upon encountering corynebacteria required TLR2. Thus, macrophage activation by the corynebacterial cell wall relies on TLR2-driven robust Mincle expression and the cooperative action of both receptors.

Tracing sialoglycans on cell membrane via surface-enhanced Raman scattering spectroscopy with a phenylboronic acid-based nanosensor in molecular recognition.

Sialoglycan expression is critical for assessing various diseases progression. Especially, its abnormal levels are commonly believed to be associated with tumor and metastatic cancer types. While, complicated structures, multiple types and dynamic distributions make it challenging for in situ investigating sialoglycans at the physiological status. Herein, we developed a 4-mercaptophenylboronic acid (MPBA)-based surface-enhanced Raman scattering (SERS) nanosensor to in situ study sialoglycan levels and dynamic expression processes of different cell types based on molecular recognition between phenylboronic acid and sialoglycans at physiological condition. This nanosensor is designed by the MPBA decorated silver nanoparticle (AgNP), which is unique and multifunctional because of its three-in-one role involving the Raman signal enhancer (AgNP), the sensing reporter of MPBA and the target receptor based on the recognition of phenylboronic acid and sialoglycans. When this nanosensor binds to sialoglycans, the molecular vibrational modes of MPBA will change, which can be traced by ultrasensitive SERS technique. The superiority of this study is that we built the relation between the spectral changes of MPBA (relative intensities) in molecular recognition with the sialoglycan dynamic expression of cells. We believe that our SERS strategy could be further extended to explore crucial physiological processes and significant biological system that glycans are involved in.

Isolation, Characterization and Antiproliferative Activity of New Metabolites from the South African Endemic Red Algal Species Laurencia alfredensis.

The marine red algae of the genus Laurencia have been widely studied for their structurally diverse and biologically active secondary metabolites. We report here the natural product investigation of the organic extract of a newly identified South African endemic species, Laurencia alfredensis. A sequence of column chromatography, preparative TLC and normal phase HPLC resulted in the isolation of eleven compounds comprising three labdane-type diterpenes (1-3), four polyether triterpenes (4-7), three cholestane-type ecdysteroids (8-10) and a glycolipid (11). Compounds 1-3, 5-8 and 10 have not previously been reported, while compound 9 is reported here for the first time from a natural source and the known compound 11 isolated for the first time from the genus Laurencia. The structural elucidation and the relative configuration assignments of the compounds were accomplished by extensive use of 1D- and 2D-NMR, HR-ESI-MS, UV and IR spectroscopic techniques, while the absolute configuration of compound 1 was determined by single-crystal X-ray diffraction analysis. All compounds were evaluated against the MDA-MB-231 breast and HeLa cervical cancer cell lines. Compound 2 exhibited low micromolar antiproliferative activity (IC50 = 9.3 µM) against the triple negative breast carcinoma and compound 7 was similarly active (IC50 = 8.8 µM) against the cervical cancer cell line.

In Vitro and in Vivo Anticancer Activity of Sophorolipids to Human Cervical Cancer.

Six characteristic di-acetylated lactonic sophorolipids with C16:1, C16:0, C18:0, C18:1, C18:2, and C18:3 fatty acid were obtained from Starmerella bombicola CGMCC 1576. In order to confirm their anticancer activity against human cervical cancer cells and reveal the structure-activity relationships, their anti-proliferation effects on HeLa and CaSki cells were estimated. The cytotoxicity of sophorolipid molecules with different degrees of unsaturation was proved to be influenced by carbon chain length of sophorolipids. The longer the carbon chain length, the stronger the cytotoxicity of sophorolipids. The inhibitory mechanism of a di-acetylated lactonic C18:1 sophorolipid on HeLa cells was investigated. The cells developed many features of apoptosis and cell cycle was blocked at G0 phase and partly at G2 phase. The expression of CHOP and Bip/GRP78 was induced. Caspase-12 and caspase-3 were both activated. However, mitochondrial membrane potential and concentration of cytosolic cytochrome C did not change. The induced apoptosis of HeLa cells was probably triggered through endoplasmic reticulum signaling pathway without involvement of mitochondria. In vivo, 5, 50, and 500 mg/kg lactonic sophorolipids showed 29.90, 41.24, and 52.06 % of inhibition without significant toxicity to tumor-bearing mice, respectively. Our findings may suggest a potential use of sophorolipids in human cervical cancer treatment.

Bartolosides E-K from a Marine Coccoid Cyanobacterium.

The glycosylated and halogenated dialkylresorcinol (DAR) compounds bartolosides A-D (1-4) were recently discovered from marine cyanobacteria and represent a novel family of glycolipids, encoded by the brt biosynthetic gene cluster. Here, we report the isolation and NMR- and MS-based structure elucidation of monoglycosylated bartolosides E-K (5-11), obtained from Synechocystis salina LEGE 06099, a strain closely related to the cyanobacterium that produces the diglycosylated 2-4. In addition, a genome region containing orthologues of brt genes was identified in this cyanobacterium. Interestingly, the major bartoloside in S. salina LEGE 06099 was 1 (above 0.5% dry wt), originally isolated from the phylogenetically distant filamentous cyanobacterium Nodosilinea sp. LEGE 06102. Compounds 5-11 are analogues of 1, with different alkyl chain lengths or halogenation patterns. Their structures and the organization of the brt genes suggest that the DAR-forming ketosynthase BrtD can generate structural diversity by accepting fatty acyl-derived substrates of varying length. Compound 9 features a rare midchain gem-dichloro moiety, indicating that the putative halogenase BrtJ is able to act twice on the same midchain carbon.

Biosurfactant/s from Lactobacilli species: Properties, challenges and potential biomedical applications.

Lactic acid bacteria are generally believed to have positive roles in maintaining good health and immune system in humans. A number of Lactobacilli spp. are known to produce important metabolites, among which biosurfactants in particular have shown antimicrobial activity against several pathogens in the intestinal tract and female urogenital tract partly through interfering with biofilm formation and adhesion to the epithelial cells surfaces. Around 46 reports are documented on biosurfactant production from Lactobacillus spp. of which six can be broadly classified as cell free biosurfactant and 40 as cell associated biosurfactants and only approximately 50% of those have reported on the structural composition which, in order of occurrence were mainly proteinaceous, glycolipidic, glycoproteins, or glycolipopeptides in nature. Due to the proteinaceous nature, most biosurfactant produced by strains of Lactobacillus are generally believed to be surlactin type with high potential toward impeding pathogens adherence. Researchers have recently focused on the anti-adhesive and antibiofilm properties of Lactobacilli-derived biosurfactants. This review briefly discusses the significance of Lactobacilli-derived biosurfactants and their potential applications in various fields. In addition, we highlight the exceptional prospects and challenges in fermentation economics of Lactobacillus spp.-derived biosurfactants' production processes.

Inhibitory Effect of Sophorolipid on Candida albicans Biofilm Formation and Hyphal Growth.

Candida albicans causes superficial and life-threatening systemic infections. These are difficult to treat often due to drug resistance, particularly because C. albicans biofilms are inherently resistant to most antifungals. Sophorolipid (SL), a glycolipid biosurfactant, has been shown to have antimicrobial and anticancer properties. In this study, we investigated the effect of SL on C. albicans biofilm formation and preformed biofilms. SL was found to inhibit C. albicans biofilm formation as well as reduce the viability of preformed biofilms. Moreover, SL, when used along with amphotericin B (AmB) or fluconazole (FLZ), was found to act synergistically against biofilm formation and preformed biofilms. Effect of SL on C. albicans biofilm formation was further visualized by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM), which revealed absence of hyphae, typical biofilm architecture and alteration in the morphology of biofilm cells. We also found that SL downregulates the expression of hypha specific genes HWP1, ALS1, ALS3, ECE1 and SAP4, which possibly explains the inhibitory effect of SL on hyphae and biofilm formation.

Production of rhamnolipids and diesel oil degradation by bacteria isolated from soil contaminated by petroleum.

Biosurfactants are microbial secondary metabolites. The most studied are rhamnolipids, which decrease the surface tension and have emulsifying capacity. In this study, the production of biosurfactants, with emphasis on rhamnolipids, and diesel oil degradation by 18 strains of bacteria isolated from waste landfill soil contaminated by petroleum was analyzed. Among the studied bacteria, gram-positive endospore forming rods (39%), gram positive rods without endospores (17%), and gram-negative rods (44%) were found. The following methods were used to test for biosurfactant production: oil spreading, emulsification, and hemolytic activity. All strains showed the ability to disperse the diesel oil, while 77% and 44% of the strains showed hemolysis and emulsification of diesel oil, respectively. Rhamnolipids production was observed in four strains that were classified on the basis of the 16S rRNA sequences as Pseudomonas aeruginosa. Only those strains showed the rhlAB gene involved in rhamnolipids synthesis, and antibacterial activity against Escherichia coli, P. aeruginosa, Staphylococcus aureus, Bacillus cereus, Erwinia carotovora, and Ralstonia solanacearum. The highest production of rhamnolipids was 565.7 mg/L observed in mineral medium containing olive oil (pH 8). With regard to the capacity to degrade diesel oil, it was observed that 7 strains were positive in reduction of the dye 2,6-dichlorophenolindophenol (2,6-DCPIP) while 16 had the gene alkane mono-oxygenase (alkB), and the producers of rhamnolipids were positive in both tests. Several bacterial strains have shown high potential to be explored further for bioremediation purposes due to their simultaneous ability to emulsify, disperse, and degrade diesel oil. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 32:262-270, 2016.