Isolation and characterization of two glycolipopeptids biosurfactants produced by a Lactiplantibacillus plantarum OL5 strain isolated from green olive curing water.

Microbial surfactants are natural amphiphilic compounds with high surface activities and emulsifying properties. Due to their structural diversity, low toxicity, biodegradability, and chemical stability in different conditions, these molecules are potential substitutes for chemical surfactants; their interest has grown significantly over the last decade. The current study focuses on the isolation, identification, and characterization of a lactic acid bacteria that produce two forms of biosurfactants. The OL5 strain was isolated from green olive fermentation and identified using MALDI/TOF and DNAr16S amplification. Emulsification activity and surface tension measurements were used to estimate biosurfactant production. The two biosurfactants derived from Lactiplantibacillus plantarum OL5 presented good emulsification powers in the presence of various oils. They were also shown to have the potential to reduce water surface tension from 69 mN/m to 34 mN/m and 37 mN/m within a critical micelle concentration (CMC) of 7 mg/ml and 1.8 mg/ml, respectively, for cell bound and extracellular biosurfactants. Thin layer chromatography (TLC) and FT-IR were used to analyze the composition of the two biosurfactants produced. the obtained data revealed that the two biomolecules consist of a mixture of carbohydrates, lipids and proteins. We demonstrated that they are two anionic biosurfactants with glycolipopeptide nature which are stable in extreme conditions of temperature, pH and salinity.

Glycolipopeptide biosurfactant from Bacillus pumilus SG: physicochemical characterization, optimization, antibiofilm and antimicrobial activity evaluation.

The Bacillus pumilus SG isolated from soil samples at the Persian Gulf was analyzed for its ability to produce biosurfactant. Various screening techniques were used for evaluating biosurfactant production and confirming biosurfactant presence in the culture supernatant. Most n-alkanes in the bacterial culture media were effectively degraded in the presence of biosurfactant acquired from the bacteria. The highest interfacial tension (IT) reduction (42 mN/m) was obtained at 24-h fermentation time (exponential phase) and did not change significantly afterwards. The glycolipid structure of the biosurfactant was revealed through NMR and FTIR spectroscopy analysis. Two-level factorial design was then applied for optimization of biosurfactant production, where a maximal reduction of culture broth IT (30 mN/m) acquired in the presence of crude oil (0.5%, v/v), NaNO3 (1 g/L), yeast extract (1 g/L), peptone (2 g/L) and temperature of 25 °C. The produced biosurfactant that exhibited a critical micelle concentration of 0.1 mg/ml was thermally stable. The glycolipid biosurfactant also displayed significant antibacterial activities against both Gram-positive and Gram-negative bacteria. The maximum inhibition of glycolipids biosurfactant was found against Acinetobacter strains (zone of inhibition, 45 mm). In addition, antibiofilm activities with a 50-90% biofilm reduction percent were indicated by the glycolipid biosurfactant. In conclusion, the glycolipid biosurfactant produced by B. pumilus SG revealed a wide range of functional properties and was verified as a good candidate for biomedical application. In conclusion, the glycolipid biosurfactant produced by B. pumilus SG showed a wide range of functional properties in this study, and in the case of further in vivo studies, it can be investigated a good candidate for biomedical applications such as use against biofilm or in pharmaceutical formulations.

Characterization and cytotoxicity assessment of biosurfactant derived from Lactobacillus pentosus NCIM 2912.

Noteworthy properties of biosurfactant (BS) are fascinating scientific fraternity to explore them for food, medicinal, cosmetic, or pharmaceutical etc. applications. Newer products intended for pharmaceutical purposes are mandatory to go through pragmatic evaluation protocols. BS, being less cytotoxic, offers an ideal candidature for widespread applications in the healthcare sector. The goal of the current study was the isolation, physico-chemical characterization, and safety assessment of cell-associated biosurfactant (CABS) from Lactobacillus pentosus NCIM 2912. The culture was grown in a 3-L fermentor to produce CABS from the cell pellets through procedures like centrifugation, filtration, dialysis, column chromatography, and freeze-drying. Further, physical properties like surface tension (ST), critical micelle concentration (CMC), contact angle (CA), emulsification activity, stability of emulsion (height of emulsion, the extent of coalescence, and appearance), and ionic character of CABS were evaluated. Analytical characterization through TLC, FTIR, NMR, and GC-MS was carried out. The physico-chemical characterization revealed CABS as an anionic, multicomponent glycolipopeptide having a hydrophobic chain comprising butanoic acid (C4), decanoic acid (C10), undecanoic acid (C11), tridecanoic acid (C13), hexadecenoic acid (C16), and octadecanoic acid (C18). The oil-in-water (O/W) emulsions formed by CABS with various oils (olive, sesame, soybean, coconut) were stabilized up to the 7th day of storage and were analogous with polysorbate 80 (emulsifier/defoamer used in food industries). The O/W emulsions are quite stable at room temperature with no evidence of coalescence of droplets around 1 week. The cytotoxicity of CABS was evaluated through MTT (3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide) assay. Cytotoxicity study performed on the human embryonic kidney (HEK 293), mouse fibroblast ATCC L929 and human epithelial type (HEP-2) cell lines recorded viability of 90.3 ± 0.1%, 99.2 ± 0.43, and 94.3 ± 0.2% respectively. The toxicity of the BS was comparable to that of the commercially used rhamnolipid sample. Thus, CABS derived from L. pentosus NCIM 2912 pose promising applications in the pharmaceutical, food industries acquiescently. The multifunctional potential of the incredibly versatile microbial product like BS from lactic acid bacteria (LAB) certainly contributes to wider avenues for varied industries.

Statistical and Artificial Neural Network Approaches to Modeling and Optimization of Fermentation Conditions for Production of a Surface/Bioactive Glyco-lipo-peptide.

A freshwater alkaliphilic strain of Pseudomonas aeruginosa, grown on waste frying oil-basal medium, produced a surface-active metabolite identified as glycolipopeptide. Bioprocess conditions namely temperature, pH, agitation and duration were comparatively modeled using statistical and artificial neural network (ANN) methods to predict and optimize product yield using the matrix of a central composite rotatable design (CCRD). Response surface methodology (RSM) was the statistical approach while a feed-forward neural network, trained with Levenberg-Marquardt back-propagation algorithm, was the neural network method. Glycolipopeptide model was predicted by a significant (P < 0.001, R 2 of 0.9923) quadratic function of the RSM with a mean squared error (MSE) of 3.6661. The neural network model, on the other hand, returned an R 2 value of 0.9964 with an MSE of 1.7844. From all error metrics considered, ANN glycolipopeptide model significantly (P < 0.01) outperformed RSM counterpart in predictive modeling capability. Optimization of factor levels for maximum glycolipopeptide concentration produced bioprocess conditions of 32 °C for temperature, 7.6 for pH, agitation speed of 130 rpm and a fermentation time of 66 h, at a combined desirability function of 0.872. The glycosylated lipid-tailed peptide demonstrated significant anti-bacterial activity (MIC = 8.125 µg/mL) against Proteus vulgaris, dose-dependent anti-biofilm activities against Escherichia coli (83%) and Candida dubliniensis (90%) in 24 h and an equally dose-dependent cytotoxic activity against human breast (MCF-7: IC50 = 65.12 µg/mL) and cervical (HeLa: IC50 = 16.44 µg/mL) cancer cell lines. The glycolipopeptide compound is recommended for further studies and trials for application in human cancer therapy.