Emulsification Index Research Articles

Heavily polluted mechanic workshop soil and its phenanthrene-degrading Bacillus thuringiensis

Mechanic workshops in residential areas are sites referenced for small-scale chronic contamination with petroleum hydrocarbons (HC) and associated pollutants like heavy metals. The main aim of this study was to isolate from a mechanic workshop soil in Lagos a novel indigenous bacterium with potential for degradation of phenanthrene, a model polyaromatic compound. Gas chromatographic analysis revealed concentrations of HC (20,055 mg kg-1), lead (156.19 mg kg-1) and zinc (202.005 mg kg-1) in excess of regulatory limits in the soil. Continuous enrichment resulted in the isolation of a bacterium strain ALSL2, which was identified by 16S rRNA gene sequencing as Bacillus thuringiensis. Strain ALSL2 showed broad specificity for a range of HCs including phenanthrene, anthracene, biphenyl, dibenzothiophene, crude oil, diesel and kerosene and also showed biosurfactant production with emulsification index 55.2 %, 65.7 % and 58.7 % on crude oil, kerosene and vegetable oil respectively. The isolate showed evidence of dioxygenase activity and utilized metabolites of aromatic hydrocarbon degradation including 1-naphthol and O-phthalate. At the end of 10 days 51.45 % of phenanthrene was degraded at the rate of 7.922 mg l−1 d−1, degradation constant 0.073 d−1, and half-life 9.864 d. The corresponding values for anthracene were 69.11 %, 9.92 mg l−1 d−1., 0.11 d−1, and 5.924 d respectively. Our findings represent a remarkable addition to available indigenous bioresources with potential for application in bioremediation, and further highlight mechanic workshop soils as veritable source of such isolate.

Isolation and Identification of Bacterial Biosurfactant Producing Strain from Soil and Evaluation of Their Antimicrobial Activity Mediated Zinc Oxide Nanoparticles

Nanoparticle synthesis using biosurfactants is currently a popular and environmentally friendly method for improving both particle synthesis and stabilization. Zinc oxide nanoparticles (ZnO NPs) have found extensive applications in the field of biomedicine. The present study focused on isolating microorganisms that produce biosurfactants from soil contaminated with oil. The isolated microorganisms were identified through molecular identification of 16s r-RNA gene sequencing and characterization as Bacillus pseudomycoides. We determined biosurfactant production using various assays such as hemolysis assay, emulsification index, oil spreading tests, and drop-collapsing assays. This investigation confirms that isolated microorganisms possess biosurfactant properties. We utilized a biosurfactant extract from the B. pseudomycoides strain for the synthesis of ZnO NPs. Advanced techniques such as UV-vis spectroscopy, XRD, FTIR, SEM, and Edax were employed to ensure accurate characterization. Furthermore, the biosurfactant-mediated ZnO NPs effectively killed a few bacterial pathogens, such as Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumonia. They were also effective against fungal pathogens, such as Aspergillus niger, Aspergillus flavus, and Fusarium oxysporum. This research highlights the impressive effectiveness of newly synthesized biosurfactant-mediated ZnO against clinical isolates. This research suggests that the biosurfactant extract from B. pseudomycoides could be used to make ZnO nanoparticles that could be useful for treating harmful infections.

Isolation and Identification of Bacterial Biosurfactant Activity from Mangrove Sediments

Background: Ujung Pangkah mangroves are reported to have been contaminated with heavy metals. Such heavy metals can induce microorganisms to produce biosurfactants. Biosurfactants with amphiphilic characteristics can lower surface tension. Biosurfactants can be used as antibacterial, antifungal, and antiviral for biomedical purposes. Purpose: This study aimed to identify and test the activity of biosurfactant isolates of bacteria from Ujung Pangkah Mangrove sediments, Gresik Regency. Methods: Biosurfactant activity test methods include emulsification index, oil spreading, drop collapse, and parafilm test. Results: The results of the identification of bacterial isolates in this study obtained the genus Bacillus sp. because bacterial isolates show rod shape, Gram-positive, aerobic, and have ellipse-shaped endospores on the subterminal. The results of the biosurfactant activity test with the Emulsification index method showed an average result of 54.39% and the results of the biosurfactant activity test with the oil spreading method showed that there was a clear zone. The average result of the clear zone obtained is 54.83 mm. The average result in the parafilm test was 8.02 mm and the drop collapse test showed positive results characterized by falling and spreading of bacterial isolate fermentation broth supernatants.

Effect of different amphiphilic emulsifiers complexed with xanthan gum on the stability of walnut milk and structural characterization of their complexes

The kind of compounding emulsifier used and the amount of compounding have a significant impact on the emulsion's stability. In this study, the average particle size, Zeta potential, emulsification index, laser confocal microstructure, and rheological properties shows that the ratio of monoglyceride-xanthan gum and sucrose ester-xanthan gum could maintain the good stability of the emulsion in a certain range, and the monoglyceride and sucrose ester compounding could effectively improve the stability of the emulsion in a specific ratio (7:3). The results of fluorescence spectroscopy, Fourier transform infrared spectroscopy and sodium dodecyl sulfate polyacrylamide gel electrophoresis indicated that the simultaneous complexation of three substances was more likely to produce hydrophobic interactions with walnut proteins than the simultaneous complexation of two substances. Also confirmed were the hydrogen bonding connections between the proteins and the monoglyceride, sucrose ester, and xanthan gum. Monoglyceride and xanthan gum complexes were also found to stabilize more proteins.

Airlift bioreactors for bioremediation of water contaminated with hydrocarbons in agricultural regions

Abstract The superficial gas velocity (Ug) values of 1.0, 1.5 and 2.0 cm s−1 showed a diesel consumption of 59.70, 58.20 and 65.20 %, respectively. The productivity of the airlift bioreactors (ALBs) was 0.030, 0.026 and 0.034 g L−1 d−1, respectively. During 10 days of operation, the emulsification index (E 24 %) values for Ug 1.0, 2.0 and 2.0 cm s−1 were 15.79, 15.07 and 12.85 %, respectively. Likewise, an increase in the degradation and suspended solids was observed when increasing the Ug from 1.0 to 2.0 cm s−1 of the ALBs, whereas a decrease in emulsification index E 24 % was observed for an Ug of 2.0 cm s−1. According to the results, the Ug of 2.0 cm s−1 was the most effective for increasing the degradation of diesel and growth of the consortium among the Ug evaluated. Furthermore, the reduction of E 24 % in this Ug suggests that the consortium uses a mixed form of hydrocarbon consumption, both by direct contact and in emulsified form.

Biosurfactant production potentials of microorganisms isolated from atmosphere of five petroleum stations at Tanke, Ilorin, Kwara State, Nigeria

Biosurfactants aid in bioremediation by improving the bioavailability of hydrocarbon contaminants. The objective of this work was to isolate, enumerate and identify bacteria and fungi for their biosurfactant production potential in the atmosphere of five petroleum stations at Tanke, Ilorin, Kwara State, Nigeria using appropriate, standard microbiological methods (haemolysis test, emulsification index test, drop collapse test and oil displacement test). Fourteen bacteria and ten fungi were isolated in this study. The bacterial isolates belong to the genus Bacillus, Corynebacterium, Micrococcus, Staphylococcus, Listeria, Clostridium. The fungal isolates are of the genus Neurospora, Curvularia, Aspergillus, Fusarium, Rhizopus, Cladosporium, Colletotrichum, Sclerotinia. The mean number of bacteria counted during the sampling ranged from 3.48±1.15*102 CFU to 4.82 ±1.69*102 CFU, with petrol station 4 having the highest bacteria count (2.41*102 CFU) and petrol station 3 having the lowest bacteria count (1.74*102 CFU). The mean fungal count ranged from 7±3.7 CFU to 8.6±4.7 *102 CFU, with petrol station 4 having the highest fungal count (4.3 *10 CFU) and petrol station 3 having the lowest fungal count (3.4*10 CFU). Bacillus species showed promise of biosurfactant production after screening. Aspergillus fumigatus was the most prevalent fungus isolated (24%) while Staphylococcus epidermidis was the most prevalent bacterium isolated (11%). Some of these organisms are known opportunistic pathogens therefore, improved ventilation and sanitation of the petrol stations should be carried out to reduce the microbial load in the air. Also, bacteria that produce biosurfactant can be isolated from air of gas stations.

Utilizing chitooligosaccharides from shrimp waste biodegradation via recombinant chitinase A: a promising approach for emulsifying hydrocarbon and bioremediation

BackgroundHydrocarbon pollution stemming from petrochemical activities is a significant global environmental concern. Bioremediation, employing microbial chitinase-based bioproducts to detoxify or remove contaminants, presents an intriguing solution for addressing hydrocarbon pollution. Chitooligosaccharides, a product of chitin degradation by chitinase enzymes, emerge as key components in this process. Utilizing chitinaceous wastes as a cost-effective substrate, microbial chitinase can be harnessed to produce Chitooligosaccharides. This investigation explores two strategies to enhance chitinase productivity, firstly, statistical optimization by the Plackett Burman design approach to evaluating the influence of individual physical and chemical parameters on chitinase production, Followed by response surface methodology (RSM) which delvs into the interactions among these factors to optimize chitinase production. Second, to further boost chitinase production, we employed heterologous expression of the chitinase-encoding gene in E. coli BL21(DE3) using a suitable vector. Enhancing chitinase activity not only boosts productivity but also augments the production of Chitooligosaccharides, which are found to be used as emulsifiers.ResultsIn this study, we focused on optimizing the production of chitinase A from S. marcescens using the Plackett Burman design and response surface methods. This approach led to achieving a maximum activity of 78.65 U/mL. Subsequently, we cloned and expressed the gene responsible for chitinase A in E. coli BL21(DE3). The gene sequence, named SmChiA, spans 1692 base pairs, encoding 563 amino acids with a molecular weight of approximately 58 kDa. This sequence has been deposited in the NCBI GenBank under the accession number "OR643436". The purified recombinant chitinase exhibited a remarkable activity of 228.085 U/mL, with optimal conditions at a pH of 5.5 and a temperature of 65 °C. This activity was 2.9 times higher than that of the optimized enzyme. We then employed the recombinant chitinase A to effectively hydrolyze shrimp waste, yielding chitooligosaccharides (COS) at a rate of 33% of the substrate. The structure of the COS was confirmed through NMR and mass spectrometry analyses. Moreover, the COS demonstrated its utility by forming stable emulsions with various hydrocarbons. Its emulsification index remained stable across a wide range of salinity, pH, and temperature conditions. We further observed that the COS facilitated the recovery of motor oil, burned motor oil, and aniline from polluted sand. Gravimetric assessment of residual hydrocarbons showed a correlation with FTIR analyses, indicating the efficacy of COS in remediation efforts.ConclusionsThe recombinant chitinase holds significant promise for the biological conversion of chitinaceous wastes into chitooligosaccharides (COS), which proved its potential in bioremediation efforts targeting hydrocarbon-contaminated sand.

Preparation of Pickering emulsion stabilized by novel amphiphilic silicon quantum dots and its application in enhanced oil recovery

In this article, a three-step method was suggested for synthesizing amphiphilic silicon quantum dots (A-SiQDs) through a simple and mild reaction process. The A-SiQDs were used to stabilize the Pickering emulsion. The A-SiQDs were characterized by high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectrometer (FTIR), X-ray photoelectron spectrometer (XPS), and dynamic light scattering (DLS). The A-SiQDs had high interfacial modulus and can reduce the interfacial tension from 20.69 mN·m−1 to 1.97 mN·m−1. Moreover, A-SiQDs had the ability to alter the wettability of the core from oil-wet to water-wet. The Pickering emulsion stabilized by 0.2 wt% A-SiQDs can still maintain more than 70% of the emulsion index (EI) after 30 days. And the Pickering emulsion exhibited excellent stability even at 90 °C. It was found that the addition of salts can improve the stability of emulsion. The network structure formed by the hydrogen bonds and hydrophobic interactions between A-SiQDs around the emulsion droplets results in enhancing shear resistance and stability of the Pickering emulsion. The Pickering emulsion flooding and microscopic visualization displacement results indicated that the Pickering emulsion can increase oil recovery by 17.9% through reducing the water–oil mobility ratio and expanding the swept area. This paper proposes a simple and innovative method for the synthesis of A-SiQDs and also provides a new nanoparticle with better performance for stabilizing Pickering emulsion.

Isolation and Characterization of Glycolipid Biosurfactant Produced by Marine Bacterium Cobetia marina Strain F1 and Investigation of Antimicrobial and Anti-Biofilm Activity

The marine environment is a rich source of microorganisms producing bioactive compounds, like biosurfactant-producing bacteria that exhibit unique characteristics and functionalities. In this study, we examined glycolipid biosurfactants produced by bacteria that live commensally with marine organisms. We isolated a biosurfactant-producing strain identified as Cobetia marina strain F1, which displayed high hemolytic activity (27 mm), oil spreading ability (4 mm), emulsification index (40%), and decreasing surface tension to 31.3 (mN·m−1). Fourier transform infrared (FT-IR) spectroscopy revealed the glycolipid composition of the biosurfactant. Furthermore, elemental analysis utilizing CHNS and energy-dispersive X-ray spectroscopy (EDS) confirmed the biosurfactant contained carbon, hydrogen, nitrogen, sulfur, chlorine, potassium, oxygen, and additional elements. The critical micelle concentration (CMC) of the crude biosurfactant was determined to be 350 mg·L−1, at which concentration, a decrease in surface tension was observed when the biosurfactant was dissolved in distilled water. Given the presence of impurities in the biosurfactant composition, this observed CMC is considered acceptable. Furthermore, the biosurfactant exhibited significant antimicrobial activity against both Gram-positive and Gram-negative bacterial strains, with the largest zone of inhibition (ZOI) of 27 mm against Pseudomonas aeruginosa. This demonstrates the potential of the biosurfactant to serve as an alternative to novel antibiotic agents. The biosurfactant exhibited considerable inhibition of biofilm formation, disruption of preformed biofilms, and reduced enzymatic activity in bacterial cells following treatment. Moreover, the combination of the biosurfactant and F1 bacterial strain enhanced the degradation of crude oil by 86%, indicating its potential application in environmental remediation. These findings highlight the importance of investigating commensal strains capable to produce biosurfactants for applications in hydrocarbon remediation, overcoming antibiotic resistance, and biofilm disruption.

Yarrowia lipolytica CMGB32 Biosurfactants Produced Using n-Hexadecane: Developing Strategies for Environmental Remediation

The yeast Yarrowia lipolytica degrades petroleum compounds, including alkanes, via the monoterminal oxidation pathway, the hydrophobic carbon substrate assimilation is mediated by biosurfactants, and extracellular amphiphilic molecules are produced by the yeast cell. This study focuses on the ability of the strain Y. lipolytica CMGB32 to degrade n-hexadecane by producing biosurfactants with high potential for bioremediation. The hydrocarbon-degrading potential of the yeast strain was observed via a 2,6-dichlorophenolindophenol (DCPIP) test in Bushnell–Hass medium with 1% n-hexadecane, and cell hydrophobicity was expressed as microbial adhesion to hydrocarbons (MATH). Biosurfactant production on yeast peptone (YP) with 1% n-hexadecane was estimated after 72 h using the emulsification index (E24%) against toluene. Crude biosurfactant (cell-free broth) stability tests were performed at different temperatures (4 °C, 70 °C) and NaCl concentrations (2–10%). The effects of a biosurfactant on synthetic wastewater remediation comprised the growth curves (OD measurements) of natural heavy metal degrader Rhodotorula mucilaginosa, determination of nutrients (spectrophotometrically), physico-chemical parameters, and removal capacity of lead and cadmium ions (via inductively coupled plasma mass spectrometry—ICP-MS). The antimicrobial and anti-adherence activities of 20 mg/mL and 40 mg/mL of the biosurfactant against pathogenic Candida krusei strains involved growth observations and the crystal violet microtiter method. The DCPIP decolorization occurred after six days, corresponding to the maximum growth phase of the Y. lipolytica culture. After 72 h, the cells presented high hydrophobicity (82.61% MATH) and stable biosurfactant production (E24% 47%). The crude biosurfactant (5%) increased the growth of R. mucilaginosa strains cultivated on synthetic wastewater cultures contaminated with Pb2+ and Cd2+, increased the conductivity and COD (86%) of the samples, and determined Pb2+ (66%) and Cd2+ (42%) ions reduction. The concentrated biosurfactant inhibited C. krusei growth (70%) and biofilm adherence. In conclusion, Y. lipolytica CMGB32 shows important potential for development of biosurfactant-based technologies for the remediation of heavy-metal- and emerging pathogen-contaminated wastewaters.

Conservation techniques for promising bacteria in the oil industry to preserve biological properties

Background: The conservation of valuable bacterial strains is crucial for various scientific, industrial, and environmental applications. Microorganisms with oil-emulsifying and oil-displacing properties are potentially significant for biotechnologies applied in the oil industry, particularly in such areas as bioremediation and tertiary enhanced oil recovery. To supply enterprises with pure cultures of microorganisms, they should be constantly maintained in the collection conditions in an active state while monitoring the preservation of their biotechnological properties. Therefore, keeping microorganism strains in working conditions and preserving their valuable properties are important for almost any work with microorganisms, ranging from primary research to their use in the production of various biopreparations.
 Aim: The article focuses on studying a method for preserving bacteria that are useful in the oil industry. This method involves modifying the technique of microencapsulating microorganism cells in alginate gel by adding glycerin, which is used as an agent with biostatic action.
 Materials and methods: The subject of research are eight hydrocarbon-oxidizing cultures of microorganisms that were sourced from the Department of Biotechnology of the al-Farabi Kazakh National University. Of these, four cultures were spore-bearing, while the other four were non-spore-bearing. The research employed microbiological methods of cultivation and storage of microorganisms in both solid and liquid media under aerobic conditions. In addition, Cooper's method was used to determine oil emulsification index and statistical methods for data analysis.
 Results: It has been found that adding glycerin (15% vol.) as a biostatic to the gel-forming matrix of sodium alginate can ensure long-term (up to 6 months) cell viability for the studied bacteria in the range of 88-96% while maintaining functionality of immobilized cells. The values of the bacteria’s oil emulsification remained at the pre-conservation levels, whereas traditional storage methods result in a lower number of viable cells after six months. It should be noted that after six months of being stored in encapsulated form with glycerin, the viability of non-sporе-forming Pseudomonas cultures is lower (88-91%) than spore-forming Bacillus (95-98%). This correlation is also is observed for traditional methods.
 Conclusion: The modern method of preserving bacteria allows for their long-term storage while maintaining functionality and viability.

Biosurfactant Activity of Bacillus sp. Strain LP04 Isolate and Its Antifungal Potency against Ganoderma boninense and Fusarium sp.

Biosurfactants are a class of amphipathic molecules that various microorganisms can produce. Biosurfactants are used as biopesticides and biocontrol agents because they have antimicrobial activity, especially as antifungal agents in several species of fungal pathogens such as Ganoderma boninense and Fusarium sp. that attack crops. This study aims to detect the biosurfactant activity of Bacillus sp. and its potential as an antifungal agent against the fungi Ganoderma boninense and Fusarium sp. Biosurfactants were produced in mineral salt medium (MSM) by harvesting cell-free supernatants. Screening of biosurfactant-producing isolates was carried out using an oil-spreading assay, a hemolysis assay, and an emulsification index. The antifungal activity of the isolates was then tested using the agar diffusion method. The LP04 isolate was closely related to Bacillus thuringiensis with a 99% similarity level. It has the potential to have biosurfactant activity, which is characterized by a positive result on the oil spreading assay test and has an emulsification index of 48.33±2.87%. The cell-free supernatants of the bacterial isolate were able to inhibit the growth of Ganoderma boninense and Fusarium sp. with growth inhibition rates of 51.11% and 56.92%, respectively.

Biosurfactant production by a crude oil‐utilizing bacterium towards petroleum hydrocarbon biodegradation applications

AbstractBiosurfactants produced by microorganisms are green amphiphilic biomolecules. They have numerous advantages compared to chemical surfactants including a lower toxicity, better environmental compatibility and effective and stable properties under extreme conditions such as a wide range of temperature, pH and salinity. A highly bio‐surfactant‐producing strain of Bacillus, VTVK15 was selected among the Bacillus isolates from marine environment and oil contaminated sites in Ba Ria‐Vung Tau. Sequence analysis of 16S rDNA showed that the VTVK15 strain was 99% similar with 16s rDNA sequence of Bacillus megaterium. The suitable conditions for the bio‐surfactant production by the strain VTVK15 were 37 °C, pH 7; 2% w/v and 0.4% w/v for temperature, initial solution pH, concentration of carbon substrate (crude oil), and concentration of nitrogen substrate ((NH4)2SO4), respectively. The emulsification index (E24) increased from 51.8% to 67.7% with suitable conditions. The petroleum hydrocarbon degradation (TPH) efficiency by the strain Bacillus megaterium VTVK15 in crude oil estimated using TPH analysis was 72% after 14 days. These results revealed that the strain VTVK15 exhibited a tremendous potential for bioremediation of petroleum hydrocarbon contaminants.

Biosurfactants production by marine yeasts isolated from zoanthids and characterization of an emulsifier produced by Yarrowia lipolytica LMS 24B

The present study investigates the potential for biosurfactant production of 19 marine yeast species obtained from zoanthids. Using the emulsification index test to screen the samples produced by the marine yeasts, we verified that five isolates exhibited an emulsification index ≥50%. Additional tests were performed on such isolates, including oil displacement, drop collapse, Parafilm M assay, and surface tension measurement. The tolerance of produced biosurfactants for environmental conditions was also analyzed, especially considering the media's temperature, pH, and salinity. Moreover, the surfactant's ability to emulsify different hydrocarbon sources and to metabolize kerosene as the sole carbon source was evaluated in vitro. Our results demonstrate that yeast biosurfactants can emulsify hydrocarbon sources under different physicochemical conditions and metabolize kerosene as a carbon source. Considering the Yarrowia lipolytica LMS 24B as the yeast model for biosurfactant production from the cell's wall biomass, emulsification indexes of 61.2% were obtained, even at a high temperature of 120 °C. Furthermore, the Fourier-transform middle infrared spectroscopy (FTIR) analysis of the biosurfactant's chemical composition revealed the presence of distinct functional groups assigned to a glycoprotein complex. Considering the status of developing new bioproducts and bioprocesses nowadays, our findings bring a new perspective to biosurfactant production by marine yeasts, especially Y. lipolytica LMS 24B. In particular, the presented results validate the relevance of marine environments as valuable sources of genetic resources, i.e., yeast strains capable of metabolizing and emulsifying petroleum derivatives.

Comparative negation of amphiphile production using nutrition factors: Amyloids versus biosurfactants

Microbial amphiphiles play an important role in environmental activities such as microbial signaling, bioremediation, and biofilm formation. Microorganisms rely on their unique characteristics of interfaces to carry out critical biological functions, which are helped by amphipathic biomolecules known as amphiphiles. Bacillus amyloids aid in cell adhesion and biofilm formation. Pseudomonas sp. are essential in biofilm development and are a vital survival strategy for many bacteria. Furthermore, Pseudomonas and Bacillus are well-known for their ability to produce biosurfactants with a range of applications, including bioremediation and removing biological pollutants from different environments. The study employed 31 different media types and a range of analytical techniques to assess the presence of amyloid proteins and the absence of biosurfactants in Bacillus licheniformis K125 (GQ850525.1) and Pseudomonas fluorescens CHA0. The presence of amyloid proteins was confirmed through Congo red and thioflavin T staining. The carefully constructed medium also efficiently inhibited the synthesis of biosurfactants by these bacteria. Additionally, surface tension measurements, emulsification index, thin-layer chromatography, and high-performance thin-layer chromatography analyses indicated the absence of biosurfactants in the tested media.

Production, characterization and biomedical potential of biosurfactants produced by haloalkaliphilic archaea from Wadi El-Natrun, Egypt

Extreme halophilic archaea that can live in high saline environments can offer potential applications in different biotechnological fields. This study delves into the fascinating field of halophilic archaea and their ability to produce biosurfactants. Some strains of haloarchaea were isolated from Wadi El-Natrun and were screened for biosurfactants production in a standard basal medium using emulsification index assay. Two strains were chosen as the potential strains for surface tension reduction. They were identified as Natrialba sp. BG1 and N3. The biosurfactants production was optimized and the produced emulsifiers were partially purified and identified using FTIR and NMR. Sequential statistical optimization, Plackett–Burman (PB) and Box–Behnken Designs (BBD) were carried out using 5 factors: oil, NaCl, casamino acids, pH, and inoculum size. The most significant factors were used for the next Response Surface Methodology experiment. The final optimal conditions for biosurfactants production were the inoculum size 2% pH 11 and NaCl 250 g/L, for Natrialba sp. BG1 and inoculum size 2.2%, pH 10 and NaCl 100 g/L for Natrialba sp. N3. The produced biosurfactants were tested for wound healing and the results indicated that Natrialba sp. BG1 biosurfactants is more efficient than Natrialba sp. N3 biosurfactants. Biosurfactants extracts were tested for their cytotoxic effects on normal cell line as well as on different cancer cells using MTT assay. The findings demonstrated that varying concentrations of the biosurfactants (31.25, 62.5, 125, 250, 500 and 1000 µg/mL) exhibited cytotoxic effects on the cell lines being tested. Additionally, the outcomes unveiled the presence of anti-inflammatory and antioxidant properties for both biosurfactants. Consequently, they could potentially serve as natural, safe, and efficient novel agents for combating cancer, promoting wound healing, and providing anti-inflammatory and antioxidant benefits.

Biosurfactant production by Rhodococcus ALDO1 isolated from olive mill wastes

Rhodococcus is a genus of Gram-positive bacteria that are widely distributed in soil, water, and plants. They have a versatile metabolism that produces different kinds of compounds like biosurfactants, lipids and carotenoids, and therefore are promising for biotechnological applications. In this work, we aimed to characterize the ability of the strain Rhodococcus ALDO1 isolated from alperujo, a complex residue from the olive oil industry, to produce biosurfactants. Growing was determined by counting the number of cells and by dry weight determination Biosurfactant production was followed by xylose equivalents (μg/ml Xylose Eq.), the perimeter obtained in the oil spreading assay and the emulsification index at 24 h (E24). We found that this strain grew in different media like glucose, oil, and glycerol, and produced a biosurfactant of a glycolipid nature as suggested by FT-IR spectrum. The maximal amount of biosurfactant (18.8 ± 2.0 μg/ml Xylose Eq., perimeter = 4.17 ± 0.17 cm, and E24 = 63.1 ± 4.1 %) was obtained when Rhodococcus ALDO1 grew in the media with oil 3% + glucose 1 %. Glycerol was also a suitable substrate for biosurfactant production (8.3 ± 1.0 μg/ml Xylose Eq., perimeter = 2.84 ± 0.07 cm, and E24 = 35.7 ± 2.9 %). The biosurfactant activity is stable at salt concentrations up to 5 g/L, temperatures up to 60 °C and pHs above 9. The thermal degradation started at 220 °C which suggested that the biosurfactant is suitable for various industrial applications. These results indicated that Rhodococcus ALDO1 is a strain to be considered as a source of biocompounds with possible industrial applications obtained from cheap substrates.

Fabrication and characterization of dual-functional porous starch with both emulsification and antioxidant properties

Starchy materials with good antioxidant, emulsification and adsorption properties have potential applications in industry. To improve these properties, a Dual-functional porous starch was prepared through one-pot synthesis. In this case, octenyl succinic anhydride (OSA) and syringic acid (SA) were selected to modify the porous starch (PS) by esterification, with subsequent signals recorded by 1H NMR at 1.2 ppm and FT-IR at 1743 cm−1, indicating the formation of Dual-functional porous starch grafted by OSA and SA. N2 adsorption analysis further proved that the porous structure (2.9 m2g−1) was still maintained after modification. This was followed by measurements of droplet size distribution (34.18 ± 3.80 μm), zeta potential (−39.62 ± 1.89 mV) and emulsion index (85.10 ± 1.76 %), all of which indicated good emulsifying capacity. Meanwhile, results of radical scavenging assay proved that the Dual-functional porous starch had considerable antioxidant properties due to the introduction of SA groups. Besides, the Dual-functional porous starch also showed good resistance to digestion. These findings not only provide a novel strategy for constructing multi-functionalized starchy materials, but also open up potential applications of starch in the food and pharmaceutical industries.

Bioactive exopolysaccharide from Limosilactobacillus fermentum LAB-1: Antioxidant, anti-inflammatory, antibacterial and antibiofilm properties

Exopolysaccharides (EPS) are an intriguing group of high-molecular-weight carbohydrate polymers known for their diverse functional benefits. Our study focused on assessing the bioactive characteristics of EPS produced by Limosilactobacillus fermentum LAB1, lactic acid bacterium (LAB) isolated from the popular dairy beverage Borhani. Previous research had demonstrated its robust antimicrobial potential against various pathogens and provided genomic evidence of its EPS production. In this investigation, we verified and validated the EPS production ability of LAB1 through a battery of tests including the string test, Congo red agar test, and aniline blue agar plate method, all of which produced positive results. The EPS extracted from LAB1 displayed a high carbohydrate-to-protein ratio and exhibited a multifaceted repertoire of bioactive properties. It demonstrated antimicrobial activity against both Gram-positive and Gram-negative pathogens, and showed the ability to inhibit biofilm formation in Staphylococcus aureus (76.61%) and Escherichia coli (13.64%). Furthermore, the EPS exhibited DPPH free radical scavenging (92.25%), hydroxyl radical scavenging (87.82%), and reducing power capacity (3.1 mM/L), which indicate its substantial antioxidant potential. Additionally, the EPS sample demonstrated significant anti-inflammatory activity (75.79 %) and moderate oil emulsifying capacity with an emulsification index of 38.38%. These findings underscore the versatility of LAB1 EPS, positioning it for diverse applications and highlighting its multifunctional role across various industrial domains.

Rhamnolipids production by Pseudomonas aeruginosa RW9 using palm oil mill effluent sludge oil as a carbon source

The production of biosurfactants has garnered considerable attention in recent years due to their unique properties, which include the ability to enhance oil solubility in water, reduce surface tension, and exhibit low environmental toxicity. In this study, we investigated the production of biosurfactants by Pseudomonas aeruginosa RW9, using a renewable and non-food competitive, palm oil mill effluent (POME) sludge oil as a carbon source. Various carbon and nitrogen sources were introduced into the mineral salt medium to optimize biosurfactant production. The results demonstrated that P. aeruginosa RW9 successfully generated 1.57 g/L of rhamnolipids (RLs) biosurfactant. Liquid chromatography-mass spectrometry (LC-MS) analysis confirmed the presence of mono-RLs and di-RLs congeners. Furthermore, the RLs produced from POME sludge oil exhibited a significant reduction in surface tension, reaching 28.55 mN/m, and demonstrated efficient emulsification of diesel, with an emulsion index of up to 56.6 %. This research underscores the promising potential of using POME sludge oil as a sustainable substrate for RLs production. This approach not only adds value to a vastly available resource but also contributes to the production of environmentally friendly biochemicals.