Biosurfactant Activity Research Articles

Production, Characterization, and Application of Biosurfactant From Lactobacillus plantarum OG8 Isolated From Fermenting Maize (Zea Mays) Slurry

Abstract Biosurfactants have wide applications in several industries. However, high production costs and safety concerns have limited their comprehensive use. Twenty-five strains of lactic acid bacteria, isolated from fermenting maize slurry, were screened for biosurfactant production using the emulsification activity (E24) assay. The selected bacterium was identified molecularly using the 16S rRNA gene sequencing as Lactobacillus plantarum OG8. The effect of some cultural factors on biosurfactant production from the bacterium, using pineapple peel as a low-cost substrate, was investigated. The optimum yield of biosurfactant occurred at a 48 h incubation period, using glucose and peptone as carbon and nitrogen sources, respectively. The biosurfactant was characterized to possess mostly carbohydrates, followed by protein and lipid contents. Optima pH 10.0 and temperature 60 °C were the best for the biosurfactant activity. The biosurfactant exhibited antimicrobial activity against bacterial pathogens Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Klebsiella pneumoniae, at a concentration of 5.0 mg/mL. The use of pineapple peel as a low-cost substrate for biosurfactant production from Lactobacillus plantarum OG8 will serve for cost-effective production. The biosurfactantt produced exhibited promising properties such as thermostability and antimicrobial activity against food spoilage and pathogenes that could make it suitable for food processing and preservation.

Impact of genus (Geotrigona, Melipona, Scaptotrigona) on the targeted 1H-NMR organic profile, and authenticity test by interphase emulsion of honey processed in cerumen pots by stingless bees in Ecuador

The biodiversity of Ecuadorian stingless bees is almost 200 species. Traditional pot-honey harvest in Ecuador is mostly done from nests of the three genera selected here Geotrigona Moure, 1943, Melipona Illiger, 1806, and Scaptotrigona Moure, 1942. The 20 pot-honey samples collected from cerumen pots and three ethnic honeys “abeja de tierra”, “bermejo”, and “cushillomishki” were analyzed for qualitative and quantitative targeted 1H-NMR honey profiling, and for the Honey Authenticity Test by Interphase Emulsion (HATIE). Extensive data of targeted organic compounds (41 parameters) were identified, quantified, and described. The three honey types were compared by ANOVA. Amino acids, ethanol, hydroxymethylfurfural, aliphatic organic acids, sugars, and markers of botanical origin. The number of phases observed with the HATIE were one in Scaptotrigona and three in Geotrigona and Melipona honeys. Acetic acid (19.60 ± 1.45 g/kg) and lactic acid (24.30 ± 1.65 g/kg) were particularly high in Geotrigona honey (in contrast to 1.3 g/kg acetic acid and 1.6 g/kg lactic acid in Melipona and Scaptotrigona), and with the lowest fructose + glucose (18.39 ± 1.68) g/100g honey compared to Melipona (52.87 ± 1.75) and Scaptotrigona (52.17 ± 0.60). Three local honeys were tested using PCA (Principal Component Analysis), two were assigned with a correct declared bee origin, but “bermejo” was not a Melipona and grouped with the Scaptotrigona cluster. However after HCA (Hierarchical Cluster Analysis) the three honeys were positioned in the Melipona-Scaptotrigona cluster. This research supports targeted 1H-NMR-based profiling of pot-honey metabolomics approach for multi-parameter visualization of organic compounds, as well as descriptive and pertained multivariate statistics (HCA and PCA) to discriminate the stingless bee genus in a set of Geotrigona, Melipona and Scaptotrigona honey types. The NMR characterization of Ecuadorian honey produced by stingless bees emphasizes the need for regulatory norms. A final note on stingless bee markers in pot-honey metabolites which should be screened for those that may extract phylogenetic signals from nutritional traits of honey. Scaptotrigona vitorum honey revealed biosurfactant activity in the HATIE, originating a fingerprint Honey Biosurfactant Test (HBT) for the genus in this set of pot-honeys.

Optimization of Biosurfactant Production using Chrysene Degrading Bacteria Isolated from Marine Water

Biosurfactants were found to be a suitable candidate for environment clean-up and as an alternative to conventional treatment systems. In the present study, a polyaromatic hydrocarbon degrading organism Bacillus halotolerans was screened for its ability to produce biosurfactant during hydrocarbon degradation. The bio-surfactant activity of the organism was screened by using various methods like oil spreading technique, emulsification assay, foam height analysis and parafilm-M test. The design expert software was used to optimize the suitable conditions for the production of biosurfactants. The optimum conditions were determined as pH 6, Chrysene-100 ppm, nitrogen source -1000 ppm and at 144 hrs using the design of experiments. The organism showed good oil degradation capacity and maximum growth was achieved in 6 days. Biosurfactant obtained from the biodegradation medium was confirmed to be lipopeptide using TLC, FTIR and GCMS.

BIOPROSES PENGURAIAN LIMBAH CAIR BUANGAN INDUSTRI PANGAN DAN NON-PANGAN BERBASIS BIOSURFAKTAN

Biosurfactants are microbial metabolites that may be utilized to replace synthetic chemical surfactant in overcoming the problem of industrial wastewater pollution. Indications of the presence of biosurfactant activity may be determined through measurement of emulsification and enzymatic activity of the tested microorganisms on their growth media, which is indicated by decreasing the BOD and COD of the tested growth media containing wastewater material as an inducer added to the microbial growth medium. This research was conducted to examine several potential microbial isolates that produce biosurfactants on growth media containing mixed waste water. The results showed that some of the microbial cultures tested showed the potential to produce biosurfactants as indicated by the emulsification and enzymatic activity of the tested microbial culture. Trial on mixed industrial wastewater showed that the tested biosurfactants were able to reduce the levels of BOD (440-1300 mg/l) and COD (1240-1760 mg/l) of the wastewater samples up to low BOD levels (82 mg/l) and COD (116 mg/l), respectively, thus that it meets the requirements of the established wastewater quality standards according to the Indonesian Standard regarding with the respective BOD (50-100 mg/l, 06-6989.9-2004 SNI) and COD (100-250 mg /l, 06-6989.2-2004 SNI).Key words : biosurfactant, emulsification, microbial enzyme, wastewater, BOD, COD.

Extraction, characterization, and biosurfactant properties of extracellular polymeric substance from textile wastewater activated sludge

Textile wastewater treatment generates sludge that needs to be disposed of safely. The cost of sludge management is 50% of the total treatment cost of the wastewater. To reduce the expense, the sludge can be repurposed as a valuable resource by extracting extracellular polymeric substance (EPS). EPS contains polysaccharides, proteins, and humic substances, which are surface-active substances that act as potential biosurfactants. In this study, we investigated sludges (sludge 1 and sludge 2) from two different textile industries for EPS production. The results showed a maximum EPS yield of 179mg/g-activated sludge from the wastewater from sludge 2. The EPS from textile wastewater activated sludge had a protein/carbohydrate ratio of 0.27-0.56, lower than that of municipal activated sludge. This difference is due to variations in nitrogen/carbon ratio in these wastewaters. Based on the biosurfactant activity test, EPS from both textile wastewaters could lower the water surface tension to around 60mN/m and emulsify olive oil better than Tween 20 and 80. However, only EPS from sludge 2 showed better xylene emulsification than EPS from sludge 1 due to the difference in humic acid content.

Application of residual cooking oil to improve the production of a low-toxic biosurfactants extract

Residual cooking oil (RCO) bioconversion into value-added products is one of the best options to manage this waste. Thus, the feasibility of producing lipopeptides by Pseudomonas syringae pv tabaci using this residue is reported for the first time. Surface activity, stability, and cytotoxicity of biosurfactants were explored by surface tension, emulsification indexes (EI24), and mammalian cell viability assays. It was demonstrated that a mixture of RCO and glycerol (1:1) as carbon source increased the production titer from 1.47 to 2.70 g/L, syringopeptin being the main component. The produced lipopeptides were able to reduce the water surface tension down to38 mN/m and emulsify effectively (EI up to 67 %) a wide variety of hydrophobic compounds at 0.10 g/L. Moreover, these lipopeptides at 1.0 g/L resulted to be highly compatible with mammalian cells (viability superior to 70 %), demonstrating that at the working concentrations are non-toxic and thus, adequate for food and pharmaceutical applications.

Enhancement of Biosurfactant Production by Bacteria Isolated from Crude Oil through Adaptation Laboratory Evolution

Biosurfactant is widely used in the petroleum industry since it can increase oil recovery. However, its productivity remains economically inefficient. Through the adaptation laboratory evolution (ALE), it is possible to improve the biosurfactant productivity of targeted bacteria. This study aimed to enhance biosurfactant production by bacteria through the ALE and characterize the biosurfactant properties. Cetyltrimethylammonium bromide (CTAB) was used as a mutagen at concentrations ranging from 3.9 ppm to 10 ppm. The biosurfactant characterizations conducted were: 1) interfacial surface tension (IFT), 2) emulsification index (E24), and 3) biosurfactant structure. The biosurfactant activity from the CTAB-resistant strain (KG7') had 3.3 folds higher IFT reduction with increasing production yield (Yp/x) up to 2.6 folds (18.75 ± 1.53 mg/108 CFU) compared to wildtype (WT) (7.07 ± 0.89 mg/108 CFU). The KG7’, which was resistant at 4.5 ppm CTAB (KG7’b), was stable after the extension of the ALE process and had higher biosurfactant activity than WT. The structural properties of WT and mutant biosurfactants were both belong to the lipopeptide class. As a result, the ALE offers a potential tool for enhancing bacterial biosurfactant production.

Bioprocess development for biosurfactant production by Natrialba sp. M6 with effective direct virucidal and anti-replicative potential against HCV and HSV

Halophilic archaea is considered an promising natural source of many important metabolites. This study focused on one of the surface-active biomolecules named biosurfactants produced by haloarchaeon Natrialba sp. M6. The production trend was optimized and the product was partially purified and identified using GC–Mass spectrometry. Sequential optimization approaches, Plackett–Burman (PB) and Box–Behnken Designs (BBD) were applied to maximize the biosurfactants production from M6 strain by using 14 factors; pH, NaCl, agitation and glycerol; the most significant factors that influenced the biosurfactant production were used for Response Surface Methodology (RSM). The final optimal production conditions were agitation (150 rpm), glycerol (3%), NaCl (20.8%), pH (12) and cultivation temperature (37°C). GC–Mass spectrometry for the recovered extract revealed the presence of a diverse group of bipolar nature, hydrophobic hydrocarbon chain and charged function group. The majority of these compounds are fatty acids. Based on results of GC–MS, compositional analysis content and Zetasizer, it was proposed that the extracted biosurfactant produced by haloarchaeon Natrialba sp. M6 could be a cationic lipoprotein. The antiviral activity of such biosurfactant was investigated against hepatitis C (HCV) and herpes simplex (HSV1) viruses at its maximum safe doses (20 μg/mL and 8 μg/mL, respectively). Its mode of antiviral action was declared to be primarily via deactivating viral envelopes thus preventing viral entry. Moreover, this biosurfactant inhibited RNA polymerase- and DNA polymerase-mediated viral replication at IC50 of 2.28 and 4.39 μg/mL, respectively also. Molecular docking studies showed that surfactin resided well and was bound to the specified motif with low and accepted binding energies (ΔG = − 5.629, − 6.997 kcal/mol) respectively. Therefore, such biosurfactant could be presented as a natural safe and effective novel antiviral agent.

Draft Genome Sequences of Bacillus velezensis Strains AF_3B and OS2, Bacillus amyloliquefaciens Strain BS9, Bacillus halotolerans Strain A1, and Bacillus sp. Strain BS3, Producing Biosurfactants with Antimicrobial Potential.

ABSTRACTFive environmental Bacillus strains were sequenced, of which three were isolated from the rhizosphere of agricultural soil and one each from Attock Oil Refinery and Khewra Salt Mine in Pakistan. The strains can be used for plant growth promotion and biosurfactant activity brought about by secondary metabolites.

Isolation and Partial Characterization of Glycolipopeptide Biosurfactant Derived from A Novel Lactiplantibacillus plantarum Lbp_WAM

Biosurfactants are amphipathic molecules generated by a variety of microorganisms with different biological functions. In this study, lactic acid bacteria were screened for their emulsification properties. However, the Lactiplantibacillus plantarum strain LBpWAM was molecularly identified using 16S rRNA, and its ability to produce surface-active peptides was investigated. The biosurfactant derived from L. plantarum LBp_WAM was shown to have the potential to reduce water surface tension from 72 mN.m-1 to 32 mN/m within a critical micelle concentration (CMC) of 2.4 mg.ml-1. The emulsification index (E24) values were evaluated for sunflower oil (60 ± 3.0%), glycerol (53.9 ± 0.11 %), olive oil (49.0 ± 2.0 %), mineral oil (50.7 ± 0.60 %), hexane (36.03±0.05 %), and kerosene (31 ±0.05 %). The biosurfactant was purified using gel filtration chromatography (GFC), and the molecular weight was determined using the SDS-PAGE method, indicating an approximate molecular weight of 19 kDa. Thin-layer chromatography (TLC) and Fourier transform infrared spectroscopy (FT-IR) were used to determine the molecular structure of the obtained molecule, which was found to be composed of protein, lipid, and polysaccharides. The biosurfactant's antibacterial activity was also examined, as it showed inhibitory effects against different species of Gram-positive and Gram-negative bacteria.

Characterization and statistical optimization of biosurfactant production using Bacillus subtilis isolated from automotive oil-contaminated soil in Yola, Nigeria

The need for cost effective and ecofriendly means of producing compounds of environmental, industrial, and other biotechnological applications cannot be overemphasized. Biosurfactant from microbial sources have been identified to have the potential to substitute chemical types. This has led to the continuous bioprospecting for biosurfactant-producing microorganisms and optimization of processes for high yield biosurfactant production. Despite the widespread, high levels of oil-induced soil pollution in Yola, Nigeria and its environs, there is dearth of information on the potential application of indigenous bacteria for biosurfactant production. In this study, a Bacillus subtilis B3 strain was isolated from an automotive oil-contaminated soil in Yola, and was further used for production, characterization, and optimization of biosurfactant activity. The partially purified biosurfactant had a structural elucidation of a lipopeptide and exhibited surface tension reduction of distilled water from 72 to 29.30 mN/m. It also forms stable emulsions between pH 6-8 and temperature 60-80 °C, and a critical micelle concentration of 0.65 %. The dry weight of the purified biosurfactant was 0.25 g/L representing a 1.6-fold increase in comparison with one obtained from conventional medium with 0.16 g/L biosurfactant yield. This finding suggests that the bacterial strain isolated in this study has the potential to meet the demand for bioremediation and other industrial exploitations.

Isolation of Biosurfactant-Producing Bacteria from Petroleum- Polluted Mangrove Swamp Samples Using Selective Enrichment Procedure

Fifty-five morphologically distinct isolates were obtained from crude oil polluted mangrove swamp samples collected from Niger-Delta, region of Nigeria, using three microbiological media for selective enrichment. Isolation from the cultivation media was performed at 3 intervals (Days 3, 7 and 14). 35% of filamentous/irregular shaped colonies were obtained at longer incubation (Day 14) and 80% of colonies were gram positive rods. Cell-free supernatants from twenty-two isolates indicated biosurfactant activity in one or all test media (Nutrient medium (NB), NB + 2% glycerol and Mineral salt medium + 2% glucose) based on results from five screening tests; surface tension, emulsification index, oil displacement, drop collapse and haemolysis. These isolates demonstrated medium-dependent biosurfactant synthesis with 16 isolates producing biosurfactant in NB + 2% glycerol compared to other test media. Results of surface tension reduction ranged from 29.8 to 48.6 mN m-1 but results did not correlate well with emulsification index, hence combination of screening methods was essential for confirmation of biosurfactant-producing isolates. 16SrRNA sequencing identified isolates belonging to Bacillus, Serratia and Paenibacillus genera. Among these isolates, SB14-1 identified as Bacillus humi utilised three test media showing ST reduction (34.1 to 48.6 mN m-1) and emulsification of paraffin oil (49.1 to 62.6%). To date, there are no reports of biosurfactant synthesis from Bacillus humi amongst other Bacillus species. The use of selective enrichment media and combination of biosurfactant screening tests could be a successful approach towards isolation of possibly new biosurfactant-producing strains and/or hyper-producers.

Antibiofilm and antimicrobial activity of biosurfactants from two Lactiplantibacillus pentosus strains against food and topical pathogens

The present study aims to evaluate the antimicrobial and antibiofilm properties of the biosurfactants from Lactiplantibacillus pentosus MSCIN-24 (GenBank Ac. No.: MK397507) and L. pentosus MSCIN-25 (GenBank Ac. No.: MK397508) against food spoilage and topical pathogens. The extracellular biosurfactants were produced in static broth culture at pH 6.8 ± 2, 37°C for 48 h and harvested by ethanol precipitation. The biosurfactants from these strains had the highest E24 values of 100% and 93.75% in olive oil, respectively at a minimum dose of 50 mg/ml and were thermostable and enzyme stable. These glycolipid biosurfactants had broad-spectrum antimicrobial activity against the food and topical pathogens with MIC and antibiofilm values in the range of 5 to 15 mg/ml and caused cell disruption. Thus, these broad-spectrum antibiofilm glycolipid biosurfactants could be used as potent antimicrobials against biofilm-forming food spoilage and topical pathogens. Practical applications Biofilm formation by food spoilage and topical pathogens are an important concern in the food processing industries for the health and hygiene issues of processed foods. Many commercial synthetic food preservatives show ineffective to combat these microorganisms. The biosurfactants from the food-grade Lactiplantibacillus pentosus MSCIN-24 and MSCIN-25 show promising antimicrobial and antibiofilm properties against the food spoilage and topical pathogens that could be exploited in food processing and preservation to extend their shelf life and better hygiene.

Antimicrobial and antioxidant activities of Bacillus mojavensis I4 lipopeptides and their potential application against the potato dry rot causative Fusarium solani.

Lipopeptides are diverse metabolites produced by various bacterial and fungal genera. They are known for their antimicrobial and surfactant activities with diverse environmental, pharmaceutical, and also agronomic applications as biocontrol agents. In this study, a PCR was used to confirm the presence of NRPS genes in Bacillus mojavensis I4. This bacterial strain could produce diverse lipopeptides which belong to the fengycin, and surfactin families. The antioxidant activity of I4 biosurfactants was determined through four different in vitro assays. Furthermore, antimicrobial activity assays indicated that I4 lipopeptides exhibited marked inhibitory activity against several bacterial and fungal strains. Further treatment of potato dry rot causative pathogen Fusarium solani with I4 lipopeptides demonstrated a remarkable reduction in the fungal penetration by almost 80% after 15days of incubation. The findings suggest that I4 lipopeptide is a potential biocontrol agent during potato tuber storage.

Bacteria Halotolerant from Karst Sinkholes as a Source of Biosurfactants and Bioemulsifiers.

Halotolerant bacteria with biosurfactant (BS) and bioemulsifiers (BE) activity can coexist in Karstic sinkholes with marine influence. Two sinkholes in the Yucatan peninsula were selected to isolate bacteria with BE and BS activity stable in NaCl. The optimal time, the effect of nitrogen and carbon source in the medium, and the conditions (agitation, pH and salinity) for the production of BS and BE compounds in planktonic and sessile (stimulate the formation of biofilms in cell roller) culture were determined. Eighty strains showed the highest emulsification activity (EI24 ≥ 50%) and drop-collapse ≥ 4 mm. 87% of the strains are moderately halotolerant, and 21% bordered the limit of extreme halotolerance. Twenty-four strains maintained or improved their BS and BE activity under salinity conditions at 5% and 10%, being the most active genera Bacillus, Paenibacillus and Lysinibacillus, identified by sequencing of the 16S rRNA gene. The results show that the nitrogen source positively affects the BS and BE activity, regardless of the type of culture. The sessile culture markedly stimulated BS activity with significant differences. However, we did not find a greater influence on the culture conditions. The results suggest that halotolerant bacteria from sinkholes could be implemented in bioremediation and other biotechnological applications.

Evaluation of the Effect of PGPR Strains on Tomato Growth and Suppression of Ralstonia Wilt Disease

The tomato (Lycopersicum esculentum Mill.) has substantial scope for development due to its high economic value and large export potential. Ralstonia syzygii subsp. Indonesiensis (RSI) is the cause of bacterial wilt disease which attacks the vascular system in Solanaceae. It can cause large losses in yield and has caused global concern because of its widespread distribution and attack on many important crops. The aim of this research was to identifiy and characterize the ability of indigenous rhizobacterial isolates to control RSI and promote tomato growth. The PGPR traits studied were production of hydrogen cyanide, siderophores, biosurfactant, and ammonia, and protease activity. Bacterial identification was performed using 16S rRNA. Our findings revealed that the strains identified shared some similarities with Bacillus thuringiensis strain ATCC 10792 (IR.2.3.5), B. mycoides strain ATCC 6462 (IR.1.3.4), Bacillus thuringiensis strain IAM 12077 (IR.2.2. 1), Serratia ficaria strain DSM 4569 (IR.3.1.4), Enterobacter oryzendophyticus strain REICA_082 (IR.2.2.7), Cronobacter dublinensis subsp. lausannensis strain E515 (IR.2.2.5) and S. rubidaea strain DSM 4480 (IR.2.2.6). All of the isolates were tested for a variety of abilities related to growth promotion and biocontrol.
 Keywords: Ralstonia wilt; 16S rRNA identification; PGPR traits

Biosurfactant activity of phylloplane bacteria from an ornamental plant, Colocasia esculenta L.

Abstract. Bukhori A, Suryanto D, Nurtjahja K. 2022. Biosurfactant activity of phylloplane bacteria from an ornamental plant, Colocasia esculenta L. Biodiversitas 23: 3108-3114. Biosurfactants are surface-active molecules produced by living organisms predominantly by microorganisms with amphiphilic properties. Exploration of biosurfactant-producing bacteria has been promoted to find the suitable agent for mass production in the laboratory following its biochemical and genetic modification. Leaf-colonizing bacteria or phyllosphere bacteria are of great interest, including those colonizing the surface of ornamental plants which are still understudied. This study aimed to isolate the biosurfactant-producing bacteria from an ornamental plant, Colocasia esculenta L and to determine their physical characteristics. Four bacterial isolates coded as IC1, IC3, IC4 and IC5 were recovered from the surface of C. esculenta and were tested positive for their growth under Bushnell-Haas agar + 1% olive oil (v/v) as the sole carbon source. Two isolates, namely IC3 and IC5, later molecularly identified as Bacillus cereus and Alcaligenes faecalis produced the highest biosurfactant concentration (IC3 = 157 ppm, IC5 = 106 ppm) on 10th day incubation based on a colorimetric test using rhamnolipid as a standard solution. Crude biosurfactants produced by A. faecalis IC5 showed better physical attributes than B. cereus IC3 in terms of surface tension, emulsification index, and oil spreading capability on four different hydrophobic compounds i.e., kerosene, solar fuel, octane fuel (Pertalite, Pertamax). The results of this study confirmed the existence of biosurfactant-producing bacteria in C. esculenta and the possibility of developing prominent strains for the treatment of hydrocarbon pollution in the environment.

Biosurfactant from Bacillus sp. A5F Reduces Disease Incidence of Sclerotinia sclerotiorum in Soybean Crop.

The present study was conducted to assess the biocontrol activity of biosurfactants obtained from Bacillus species A5F. The variables significantly influencing the production of biosurfactants under in vitro conditions were further optimized using response surface methodology. Optimal values of selected culture variables, i.e., glucose, soybean oil, and incubation time were 3.5gl-1, 3.5mll-1, and 78h, respectively, resulting in 2.14-fold enhancement in biosurfactant levels in 5l fermentor. Identified biosurfactants had a significant effect on chlorophyll content, shoot biomass, number of pods, and seed weight. Biosurfactants also reduced the disease incidence in S. sclerotiorum infected soybean plants and showed antagonistic action against major phytopathogens by disrupting the hyphal cell wall. 16% reduction in ITS gene copy number was observed as compared to control with less non-target effect upon biosurfactant spray on foliar parts of soybean. Thus, the study confirms that biosurfactants from strain A5F can be used as a potent biocontrol agent to control sclerotium wilt on soybean plants.

Reduction of Surface Tension of Petroleum Using Hydrocarbon Degrading Bacterial Activity

Hydrocarbon degrading bacteria produce biosurfactants, which facilitate the biodegradation process. This is the first step towards getting access to interactions between the bacteria's hydrophilic surface and the hydrophobic surface of the hydrocarbons. Due to their amphipathic nature, biosurfactants facilitate this interaction. The focus of the study is to obtain hydrocarbon-degrading bacteria isolates and evaluate biosurfactant activity in reducing water surface tension. Hydrocarbon-degrading bacteria were isolated from contaminated marine sediment samples and consequently cultured on artificial seawater media with the addition of petroleum hydrocarbons as a carbon source. Surface tension reduction of biosurfactants was measured using a digital K20-EasyDyne tensiometer (KRÜSS: Hamburg, Germany). The study indicates that the isolates have biodegradation activity and reduced water surface tension by 22.14 mN/m, the data demonstrated that biosurfactant production was most effective on the third day of the exponential phase incubation. These studies demonstrate the effectiveness of hydrocarbon-degrading bacteria to produce biosurfactants as biodegradation agents to solve the problem of oil pollution.

Lactiplantibacillus plantarum-Derived Biosurfactant Attenuates Quorum Sensing-Mediated Virulence and Biofilm Formation in Pseudomonas aeruginosa and Chromobacterium violaceum

Quorum sensing (QS) controls the expression of diverse biological traits in bacteria, including virulence factors. Any natural bioactive compound that disables the QS system is being considered as a potential strategy to prevent bacterial infection. Various biological activities of biosurfactants have been observed, including anti-QS effects. In the present study, we investigated the effectiveness of a biosurfactant derived from Lactiplantibacillus plantarum on QS-regulated virulence factors and biofilm formation in Pseudomonas aeruginosa and Chromobacterium violaceum. The structural analogues of the crude biosurfactant were identified using gas chromatography–mass spectrometry (GC–MS). Moreover, the inhibitory prospects of identified structural analogues were assessed with QS-associated CviR, LasA, and LasI ligands via in silico molecular docking analysis. An L. plantarum-derived biosurfactant showed a promising dose-dependent interference with the production of both violacein and acyl homoserine lactone (AHL) in C. violaceum. In P. aeruginosa, at a sub-MIC concentration (2.5 mg/mL), QS inhibitory activity was also demonstrated by reduction in pyocyanin (66.63%), total protease (60.95%), LasA (56.62%), and LasB elastase (51.33%) activity. The swarming motility and exopolysaccharide production were also significantly reduced in both C. violaceum (61.13%) and P. aeruginosa (53.11%). When compared with control, biofilm formation was also considerably reduced in C. violaceum (68.12%) and P. aeruginosa (59.80%). A GC–MS analysis confirmed that the crude biosurfactant derived from L. plantarum was a glycolipid type. Among all, n-hexadecanoic acid, oleic acid, and 1H-indene,1-hexadecyl-2,3-dihydro had a high affinity for CviR, LasI, and LasA, respectively. Thus, our findings suggest that the crude biosurfactant of L. plantarum can be used as a new anti-QS/antibiofilm agent against biofilm-associated pathogenesis, which warrants further investigation to uncover its therapeutic efficacy.