Potential Biosurfactant Producer Research Articles

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.

Extraction of biosurfactant from pseudomonas aeruginosa inhabiting oil-spilled soils

BackgroundScreening for biosurfactant-producing microbes involves the process of sampling and isolating bacteria from various environmental sources. Hydrocarbon-contaminated locations are considered ideal sources for isolating bacteria that produce biosurfactants. This is because these microbes have adapted to living in oil-contaminated environments and have developed mechanisms to produce biosurfactants as a means of survival. Therefore, screening microbes from such locations increases the likelihood of finding bacteria capable of producing biosurfactants.ResultsThis investigation aimed to isolate bisurfactant-producing bacteria from oil-contaminated soil samples, with a particular focus on Pseudomonas aeruginosa. Out of the 10 samples collected, four were confirmed to be P. aeruginosa, and all strains showed positive results for antagonistic, hemolytic, and emulsification tests. The strains were effective against B. subtilis, S. aureus, and E. coli but less effective against A. hydrophila. The PS10 strain exhibited the highest emulsification index, while PS08 showed the lowest. Based on microscopic and biochemical examination, P. aeruginosa was identified as the most effective isolate.ConclusionThese findings highlight the potential of P. aeruginosa as a biosurfactant producer for industrial and environmental applications. However, further studies are needed to fully understand the biosurfactant production potential of these strains and to optimize the conditions for biosurfactant production.

Diversity and Distribution of Potential Biosurfactant Producing Bacillus Sp MN 243657, GC-MS Analysis and its Antimicrobial Study

Biosurfactants are microbially produced surface-active compounds. They are amphiphilic molecules with hydrophilic and hydrophobic regions. The demand for biosurfactants has been exponentially growing as they are nontoxic and biodegradable. They have different applications in several industrial sectors. The objective of this study was to isolate and characterize the native bacteria which produce biosurfactants from oil contaminated soil of different places in Kerala and Tamil Nadu, India. The soil samples were collected from petrol pumps and workshops where the soil is contaminated with petrol, diesel and oil. The bacteria were isolated from contaminated soil samples and confirmed as Bacillus sp.The cultures were screened for biosurfactant production by different screening techniques such as blood hemolysis, oil spreading assay, emulsification ability assay, bacterial adherence to hydrocarbons activity. The potential biosurfactant producing culture was selected and identified using molecular techniques and submitted to NCBI Gene Bank (MN 243657 – Bacillus sp). The selected bacterial culture was used for biosurfactant production and these were characterized by UV, TLC, FTIR and GC -MS analysis. The derived biosurfactant's Rf value was 0.68 as determined by a TLC chromatogram. In a UV-visible spectroscopy study, the isolated biosurfactant displayed a highest peak at 415 nm. According to FTIR analysis, the isolated biosurfactant displayed an intense peak at 3340 cm -1. The large peaks of the biosurfactant were observed at various retention times of 12.75, 10.22, 4.98, and 3.87, respectively, after GC-MS analysis. Antibacterial and antifungal activity of the biosurfactant was identified against pathogenic bacteria such as P.aeruginosa, E. coli, K. pneumoniae, S. aureus and fungi Aspergillus niger, Aspergillus terreus, Aspergillus flavus.

Efficacious use of potential biosurfactant producing plant growth promoting rhizobacteria to combat petrol toxicity in Zea mays L. plants.

Soil pollution caused by petroleum hydrocarbons is a serious threat for human life, as it affects the groundwater, cause economical losses after decreasing the agricultural production, and create other ecological issues. Here, we are reporting the isolation and screening of rhizosphere bacteria possessing biosurfactant producing potential and capable of enhancing plant growth under petrol stress as well as possessing. Efficient biosurfactant producers having plant growth promoting traits were characterized morphologically, physiologically, and phylogenetically. These selected isolates were identified as Bacillus albus S2i, Paraclostridium benzoelyticum Pb4, and Proteus mirabilis Th1 based on 16S rRNA sequence analysis. These bacteria possessed plant growth promoting attributes as well as exhibited positive activity toward the assays based on hydrophobicity, lipase activity, surface activity, and hydrocarbon degradation that indicated the production of biosurfactants. Fourier transform infrared spectroscopy of crude biosurfactants extracted from bacterial strains revealed that the biosurfactants from Pb4 and Th1 might belong to glycolipid or glycolipopeptide class whereas the biosurfactants from S2i could be from phospholipid class. Scanning electron micrographs exhibited group of exopolymer matrices interconnecting the cells forming a complex network of mass, while energy dispersive X-ray analysis has shown elemental composition of biosurfactants with dominance of nitrogen, carbon, oxygen, and phosphorous. Further, these strains were then used to ascertain their effect on the growth and biochemical parameters including stress metabolites and antioxidant enzymology of Zea mays L. plants grown under petrol (gasoline) stress. Significant increments in all studied parameters were observed in comparison with control treatments that might be due to petrol degradation by bacteria and also by secreting growth stimulating substances released by these bacteria in soil ecosystem. To the best of our knowledge, this is the first report in which Pb4 and Th1 were studied as surfactant producing PGPR and further their role as biofertilizer for the significant improvement in phytochemical constituents of maize plants grown under petrol stress was assessed.

Characterization of the biosurfactant production and enzymatic potential of bacteria isolated from an oil-contaminated saline soil.

Biosurfactants are amphiphilic compounds with extensive applications in oily contaminated environments to remove hydrocarbons. Moreover, enzymes such as laccase and manganese peroxidase are responsible for the oxidation of a variety of phenolic compounds and aromatic amines. Therefore, in the present study, bacteria with the potential to produce biosurfactants and enzymes (namely, laccase, manganese peroxidase, and endoglucanase carboxymethyl cellulose (CMCase)) were isolated from petroleum oil-contaminated soil. From 15 isolated bacteria, three isolates were selected as the best producers of biosurfactants according to the related tests, such as tests for surface tension reduction. These three bacteria indicated tolerance to a salinity test and were classified as resistant and very resistant. The isolates 3, 12, 13, and 14 showed positive results for the degradation of guaiacol, phenol red, and carboxymethylcellulose, as well as the decoloration of methylene blue by the creation of a clear halo around the bacterial colony. Upon the quantitation of the laccase and manganese peroxidase activities, 22.58U/L and 21.81U/L, respectively, were measured by isolate 13. Furthermore, CMCase activity was recorded with 0.057436U/ml belonging to isolate 14. Bacterial strains with appreciable laccase, peroxidase, CMCase activity, and biosurfactant production potentials were identified through 16S rDNA sequence analysis as Bacillus sp. (isolate 3), Bacillus toyonensis (isolate 12), Bacillus cereus (isolate 13), and Bacillus tropicus (isolate 14), and their nucleotide sequences were deposited in the GenBank. The potentials for the industrial applicability of the biosurfactants and enzymes abound, and production needs to be optimized by the selected bacterial strains.

Isolation and Screening of Biosurfactant Producing Bacteria from Soil and Water for their Potential Applications

Abstract: Biosurfactants are amphiphilic compounds produced on the membrane of cells which tends to reduce surface tension. This study was done in order to isolate, screen for potential biosurfactant producing bacteria and its applications in plant growth and antimicrobial activity which were isolated from soil and water contaminated with used engine oil. Mineral salt medium(MSM) was used to isolate the bacterial strains. The isolated strains were screened for biosurfactant production by microplate assay, oil spread assay, blood haemolysis, CTAB agar assay, emulsification index test . The strains were followed through biochemical tests to study their composition. The isolated strains were run through 16s rRNA sequencing. Assessment of the properties of biosurfactant showed string antimicrobial activity against S.typhi, B.subtilis, E.coli. The biosurfactant effect on plant growth was examined and it showed improved growth in plants. The antimicrobial activity and the enhancement in the plant growth can lead to a revolution in the field of agriculture.

Enhanced production of biosurfactant by Bacillus subtilis RSL2 in semicontinuous bioreactor utilizing molasses as a sole substrate

The growth-associated metabolites are produced during the exponential phase; however, this phase terminates due to substrate depletion or product inhibition. In the present study, a semicontinuous mode with a fill-and-draw strategy was applied to extend the exponential phase of the biosurfactant production to overcome the product inhibition and in turn, enhance the yield. Bioreactor studies were performed in batch mode, followed by the semicontinuous operation. A potential biosurfactant producer Bacillus subtilis RSL2 was used in this study at the previously optimized conditions of pH 6.6, temperature 41 °C and 5% (w/v) of molasses. A better mass transfer was achieved in the bioreactor as compared to the shake flask study. In the batch bioreactor study, 90% of sugar was utilized with simultaneous 13.7 g L−1 of biosurfactant production. The sugar utilization was further improved to > 98% in the case of semicontinuous operation employing a fill-and-draw strategy. The exponential phase got extended up to 18 days and a total of 13 L of media was fed in the semicontinuous operation of 21 days as compared to 1.5 L of working volume in the batch reactor. The biosurfactant yield was enhanced by 1.5 folds and was found to be 0.97 g g−1. The produced biosurfactant was identified as a lipopeptide. The interfacial properties of the biosurfactant along with colloidal and thermal stability have been investigated. The critical micelle concentration of the produced biosurfactant was 70 mg L−1. The present study highlighted the efficient utilization of molasses for the production of biosurfactant, an alternative metabolite, in a semicontinuous mode of bioreactor.

Single-Cell-Based High-Throughput Cultivation and Functional Characterization of Biosurfactant-Producing Bacteria from Soil and Oilfield-Produced Water.

Biosurfactants are a group of surface-active compounds that can be produced by diverse microorganisms. They have been widely used in various industrial fields. Reducing production costs, improving efficiency, and collecting more diverse producing strains have become major challenges in the biosurfactant industry. These challenges could be overcome by screening for more diverse and efficient biosurfactant-producing strains. The conventional methods for the isolation and functional characterization of microorganisms are laborious and biased toward fast-growing or strongly competitive microorganisms. Here, we established a high-throughput approach of single-cell-based cultivation and functional characterization of biosurfactant-producing bacteria (SCCBB). This approach combines single-cell cultivation with the detection of optical distortions. Using this approach, we isolated 431 strains with biosurfactant production potential from petroleum-contaminated soil and oilfield-produced water. The surfactant production capabilities of the strains were subsequently validated using surface tension measurements, TLC, and CMC measurements. To investigate the industrial production potential, we optimized the production conditions of a representative glycolipids-producing strain, Pseudomonas sp. L01, using response surface methodology (RSM). Optimal conditions yielded a crude biosurfactant yield of 8.43 g/L in a flask. Our work provides a high-throughput approach to the isolation and screening of biosurfactant-producing bacteria, as well as other functional bacteria in a wide range of fields.

Characterization of bacterial community in oil-contaminated soil and its biodegradation efficiency of high molecular weight (>C40) hydrocarbon

In this study, two biosurfactant producing Pseudomonas aeruginosa sp. were isolated from motor oil contaminated soil for crude oil, alkane and PAH degradation studies. Metagenomics analysis identified as proteobacteria phyla was the dominant. Isolated two bacterial species were well grown in mineral salt medium with 1% of crude oil, alkanes (dotriacontane and tetratetracontane) and PAH (pyrene, benzopyrene and anthracene) as sole carbon sources. Total biodegradation efficiency (BE) of strains PP3 and PP4 in Crude oil degradation evaluated by the analysis of gas chromatography and mass spectrometry was 50% and 86% respectively. BE of PP3, PP4 and mixed consortium in alkane biodegradation were 46%, 47% and 36%, respectively. BE of PP3, PP4 and mixed consortium in PAH biodegradation were 22%, 48% and 35%, respectively. Based on the results revealed that strain pp4 was more efficient bacteria to degrade the crude oil, alkane and PAH than pp3. This was due to the higher production of biosurfactant by PP4 than PP3 and also confirmed in the test of emulsification index (E24). FTIR results showed that the produced biosurfactant could partially solubilize the crude oil hydrocarbons, alkanes and PAH and confirmed as glycolipid (rhamnolipid) in nature. Thus, the obtained results from the GCMS showed that all hydrocarbons were utilized by bacteria as carbon source for biosurfactant production and utilize the high molecular weight hydrocarbons. Based on the present study we can suggest that identified potential biosurfactant producing bacteria are used for biodegradation of high molecular weight hydrocarbon (>C40).

Molecular identification and primary evaluation of bio-surfactant production in edible paddy straw mushroom

Bio-surfactants have a unique structure that makes them suitable and attractive for many purposes such as removing crude oil, pharmaceutical production, oil industry (MEOR), and food industry. Using microorganisms instead of chemical surfactants for bio-surfactant production is confirmed by many researchers. So far, many efforts have been made to find more potent microorganisms for bio-surfactant production and almost all of these researches have been conducted on bacterial species and yeasts. Present study was performed in order to molecular identification and evaluation of bio-surfactant production potential of a previously isolated edible paddy straw mushroom. Bio-surfactant production by this microorganism was screened using emulsification index (E24%), oil spreading activity, and surface tension tests. DNA sequencing showed that this fungous belongs to new species of Volvariella volvacea. Also, reduction in surface tension, emulsification index and oil spreading activity were 35.15 dyne/cm, 80% and 11 cm, respectively.

Evaluation of biosurfactant production potential of Lysinibacillus fusiformis MK559526 isolated from automobile-mechanic-workshop soil.

Biosurfactants are amphipathic biological compounds with surface active potential and are produced by many microorganisms.Biosurfactant production by Lysinibacillus fusiformis MK559526 isolated from automobile-mechanic-shop soil was investigated with a view to assessing itspotential for production and potential for optimization. Effects of carbon and nitrogen sources, pH, temperature and incubationperiods on biosurfactant production were evaluated with a view to optimizing the processes. Fourier Transform Infra-Red absorption peaks and Gaschromatography mass spectrometry were used to determine the functional groups of the chemical make-up and the chemical profile of the biosurfactantrespectively. Lysinibacillus fusiformis surfactant had emulsification index of 65.15 ± 0.35 %, oil displacement of 2.7 ± 0.26 mm, zone ofhaemolysis of 7.3 ± 0.16 mm and a positive drop collapse test. Optimized culture conditions for biosurfactant production: temperature, 35 ºC; pH, 7.0;starch solution, 40 g/L and urea, 1.5 g/L showed a reduction in surface tension to 28.46 ± 1.11 mN/m and increased emulsification index to 93.80 ± 0.41 %.Maximum biosurfactant production of 2.92 ± 0.04 g/L was obtained after 72 h. The biosurfactant contained peptides and fatty acids. The predominant fattyacid was 9-Octadecenoic acid (80.80%). The above results showing high emulsification potential and remarkable reduction in the surfacetension are good biosurfactant attributes. Consequently, Lysinibacillus fusiformis MK559526 is a good candidate for biosurfactant production.

Microbial-induced biosurfactant-mediated biocatalytic approach for the bioremediation of simulated marine oil spill

Marine crude oil spill is the most alarming environmental issue and the dreadful instance of petroleum hydrocarbon pollution around the world. Successful remediation of these toxic pollutants demands for the ample production of biosurfactant and biocatalysts by the native hydrocarbon-degrading microbes. The main focus of this investigation is to determine the potential of a halo-tolerant and biosurfactant-producing hydrocarbonoclastic bacterium, Enterobacter hormaechei, for the effective bioremediation of marine oil spill. The strain had the ability to produce biosurfactant with excellent surface and emulsification activities along with biocatalysts. The activity of the extracellular enzymes such as lipase and laccase was found to be 160 U/ml and 38 U/ml, respectively, whereas the intracellular enzymes like alkane hydroxylase, alcohol dehydrogenase and esterase showed the corresponding activities of 48 U/ml, 86 U/ml and 102 U/ml. Overall, E. hormaechei could be able to degrade nearly 85% of petroleum hydrocarbons present in crude oil within 10 days of incubation. The biosurfactant was characterized to be an anionic, high molecular weight (48 kDa) lipoprotein-type biosurfactant. The biosurfactant was further characterized by Fourier transform infrared spectroscopy. The E. hormaechei was employed for the treatment of simulated marine oil spill and the degradation followed pseudo-second-order kinetics with rate constant k2 0.2775 and R2 0.9923. The crude oil degradation was confirmed by gas chromatography–mass spectrometry. The study suggested that the E. hormaechei is a potential biosurfactant and biocatalysts producer with the effective management of accidental marine oil spills.

Oil washing proficiency of biosurfactant produced by a novel Bacillus tequilensis MK 729017 isolated from Assam reservoir soil

The present study describes elaborately the isolation of a potential biosurfactant producing and crude oil degrading (1-5%) strains isolated from the Assam oil reservoir field. The produced biosurfactant was chemically characterized for its applicability for the enhanced oil recovery applications in terms of wetting, interfacial tension (IFT) and oil washing. From the seven isolated strains, Bacillus tequilensis MK 729017 was chosen based on the better surface active properties as it reduced the surface tension to 30 ± 2 mN/m along with a moderate emulsification index of 66 ± 2 %. The produced biosurfactant was chemically identified to be lipopeptide, surfactin with a lower critical micelle concentration value of 90 mg/L. The carbon source and environmental parameters were optimized for the maximum concentration of the biosurfactant using RSM-CCD. The maximum biosurfactant concentration was measured to be 7.46 ± 0.39 g/L and Y_PS was determined as 0.45. The specific growth rate of the isolate was 0.15 ± 0.01 h-1 and Y_XS was estimated as 0.1. The produced biosurfactant was also found to be thermal and colloidal stable. The biosurfactant solutions altered wettability of hydrophobic rock surface from 90 ± 1o to 26 ± 1o indicating a better interfacial interaction. The IFT of the produced biosurfactant was found to be 0.32 ± 0.02 mN/m. The oil washing efficiency (80 ± 2 %) of the produced surfactin was comparable with chemical surfactants and the process involved two-steps: initial a faster (surface) washing followed by a slower (internal) washing. The first process was dependent on micelle sizes, while the later was dependent on water-oil emulsion size. The lower emulsion size of surfactin contributed to a greater internal washing as compared to chemical surfactants. These observations endorse the potential of the isolated strain towards biosurfactant production and its application in microbial enhanced oil recovery process.

Bio-electrokinetic remediation of crude oil contaminated soil enhanced by bacterial biosurfactant

The present study evaluating the coupling between bioremediation (BIO) and electrokinetic (EK) remediation of crude oil hydrocarbon by using bio-electrokinetic (BIO-EK) technique. The application of bacterial biosurfactant (BS) may increase the remediation efficiency by increasing the solubility of organic materials. In this work, the potential biosurfactant producing marine bacteria were isolated and identified by 16S rDNA analysis namely Bacillus subtilis AS2, Bacillus licheniformis AS3 and Bacillus velezensis AS4. Biodegradation efficiency of crude oil was found as 88%, 92% and 97% for strain AS2, AS3 and AS4 respectively, with the optimum temperature of 37 °C and pH 7. FTIR confirm the BS belongs to lipopeptide in nature. GCMS reveals that three isolates degraded the lower to higher molecular weight of the crude oil (C8 to C28) effectively. Results showed that use of BS in electokinetic remediation enhance the biodegradation rate of crude oil contaminated soil about 92% than EK (60%) in 2 days operation. BS enhances the solubilization of hydrocarbon and it leads to the faster electromigration of hydrocarbon to the anodic compartment, which was confirmed by the presence of higher total organic content than the EK. This study proven that the BIO-EK combined with BS can be used to enhance in situ bioremediation of petroleum contaminated soils.

Biosurfactant production and engine oil degradation by marine halotolerant Bacillus licheniformis LRK1

Abstract In this study, a halotolerant marine bacterium Bacillus licheniformis LRK1 was studied to check its biosurfactant production potential. In substrate utilization study, the isolate was able to utilize 58 substrates out of 95 substrates studied. Biosurfactant production by the isolate was studied using various screening methods. It showed Emulsification Index (EI24) of 70% and 31.43% reduction in surface tension. Column purified biosurfactant was analyzed by Thin Layer Chromatography (TLC) and Fourier-transform Infrared Spectroscopy (FTIR) which confirmed the nature of the produced biosurfactant as lipopeptide. The maximum biosurfactant production was achieved at neutral pH, incubation temperature of 35 ± 2 °C and salinity concentration of 3% w/v. The gravimetric method showed 24.23% degradation of engine oil by the isolate after 21 days of incubation. The degradation was further confirmed by Gas Chromatography (GC) and High-performance Thin Layer Chromatography (HPTLC) analysis. This indicates that strain possesses great potential in the field of bioremediation of oil pollution in the marine environment.

Optimization of biosurfactant production from chemically mutated strain of Bacillus subtilis using waste automobile oil as low-cost substrate

In this study, we have evaluated biosurfactant production potential of locally isolated strain of Bacillus subtilis (accession # KX788864) using waste automobile oil as cost-effective substrate with waste-to-value nexus. The wild strain of B. subtilis yielded 2.1 g/L biosurfactant, showed 42% emulsification index, and 38.27 cm2 of total oil displacement. The ethidium bromide (EtBr) mutagenesis was performed by exposing native B. subtilis strain with varying concentrations of EtBr (50, 100, 150 and 200 µg/10 mL) for different time intervals of 30, 60 and 90 min. Significantly higher yield (4.2 g/L) was attained from B. subtilis MS1 exposed to EtBr (50 µg/10 mL) for 60 min confirming the positive effect of mutagenesis. The mutated strain (B. subtilis MS1) showed improved emulsification index (50.53%) and oil displacement (49.32 cm2). Fourier-transform infrared (FTIR) spectroscopy analysis of biosurfactant produced from mutated strain (B. subtilis MS1) confirmed the lipopeptide nature of biosurfactant due to the existence of amide, amine and phospholipids functional groups. The maximum surfactant yielding mutant was proceeded for optimization using response surface methodology (RSM) technique and the interaction effect of different parameters was studied that allow biosurfactant hyperproduction. After optimization, maximum biosurfactant (4.7 g/L) was obtained at pH 7, temperature 35 °C, inoculum size 3 mL and an overall incubation of 120 h. In conclusion, the economical production of biosurfactant, along with novel functional properties (i.e., oil/hydrocarbon recovery and emulsification properties), this research may be valuable for numerous bioremediation and industrial biotechnological applications.

Oil washing proficiency of biosurfactant produced by isolated Bacillus tequilensis MK 729017 from Assam reservoir soil

The present study describes elaborately the isolation of a potential biosurfactant producing and crude oil degrading strains isolated from the reservoir soil of Assam oil reservoir field. The produced biosurfactant was chemically characterized for its applicability for the enhanced oil recovery applications in terms of wetting, interfacial tension (IFT) and oil washing. From the seven isolated strains, Bacillus tequilensis MK 729017 was chosen based on the better surface active properties as it reduced the surface tension to 30 ± 2 mN/m along with a moderate emulsification index of 66 ± 2%. The produced biosurfactant was chemically identified to be lipopeptide, surfactin with a lower critical micelle concentration value of 90 mg/L. The carbon source and environmental parameters were optimized for the maximum concentration of the biosurfactant using response surface methodology based on the central composite design (RSM-CCD). The maximum biosurfactant concentration was measured to be 7.46 ± 0.39 g/L and YPS was determined as 0.45. The specific growth rate of the isolate was 0.15 ± 0.01 h−1 and YXS was estimated as 0.1. The produced biosurfactant was also found to be thermal and colloidal stable. The biosurfactant solutions altered wettability of hydrophobic rock surface from 90 ± 1° to 26 ± 1° indicating a better interfacial interaction. The IFT of the produced biosurfactant was found to be 0.32 ± 0.02 mN/m. The oil washing efficiency (80 ± 2%) of the produced surfactin was comparable with chemical surfactants and the process involved two-step: initial a faster (surface) washing followed by a slower (internal) washing. The first process was dependent on micelle sizes, while the latter was dependent on water-oil emulsion size. The lower emulsion size of surfactin contributed to a greater internal washing as compared to chemical surfactants.

Screening of biosurfactant producing yeasts isolated from mangrove ecosystem of Surat region of Gujarat, India

Background/ Objectives: Biosurfactants are extracellular surface-active compounds produced by bacteria, fungi and yeast. Interest in biosurfactant has been increasing due to their unique properties. The objective of this study is to screen for potential biosurfactant producing yeasts from mangrove areas of Gujarat in India. Methodology: The biosurfactant producing yeasts isolated from five different mangrove sites i.e. Hazira, Mandroi, Mirzapur, Kantiyajal and Machhad of Surat, Gujarat during summer season of 2015. Isolated yeasts were screened for the production of biosurfactant by Parafilm M, Oil displacement and Emulsification index method in which cottonseed oil was used as a substrate. The type of biosurfactant produced was identified by Phenol-sulfuric acid test, Biuret test and phosphate test. Findings: Total twenty four yeasts were isolated from soils of sampling sites. Yeasts were initially screened by Parafilm M and oil displacement method. Out of these 24 isolate, 6 isolates namely, Ky-48, Ky-53, Ky-54, Ky-84, Ky-86 and Ky-87 showed promising biosurfactant activity. These six isolates were further subjected to secondary screening method: Emulsification test, to identify biosurfactant production. Two isolates, namely Ky-46 (emulsification index: 61.53 %) and Ky-86 (emulsification index: 46.66 %) showed maximum biosurfactant production. All six isolates showed positive result for phenol- sulfuric acid method. This indicated that the isolated biosurfactant was Glycolipid in nature. Novelty/Applications: Few mangrove yeasts have potential to produce high amount of glycolipid that can be used in food processing and detergents, healthcare and cosmetics industries. Keywords: Biosurfactant; emulsification index; oil displacement; glycolipid

Improved biosurfactant production from Aspergillus niger through chemical mutagenesis: characterization and RSM optimization

Biosurfactants are surface-active natural polymers produced within several microorganisms and are secreted outside the cellular environment. They are the focus of modern researches due to their eco-friendly nature and high production capability using low-cost agro-industrial wastes. In this research, we have evaluated Aspergillus niger (A. niger) for its biosurfactant production potential during solid state fermentation of banana stalks powder. The native strain of A. niger produced 2.3 g/L of biosurfactant with 49.74 cm2 oil displacement, 57% emulsification index and an emulsification activity of 1.024 (OD540). Sequential mutagenesis was induced in the native strain of A. niger by exposing the strain with different concentrations of ethidium bromide (EtBr), for different time periods. Significantly higher amount of biosurfactant (3.3 g/L) was obtained from the mutant strain A. niger M2 exposed to 50 µg/10 mL of EtBr for 60 min. The screening tests revealed the improvement in oil displacement (59.81 cm2), emulsification index (62.3%) and emulsification activity (OD540, 1.262) of biosurfactant. FTIR analysis confirmed the presence of amine, amide, fatty acids and triglycerides functional groups. The maximum biosurfactant synthesizing mutant (A. niger M2) was further optimized using RSM under CCD. After optimization, the highest biosurfactant (5.50 g/L) was obtained at 35 °C temperature, 7 pH, 5.75 g substrate concentration and 168 h of overall incubation period. In conclusion, the cost-effective production of biosurfactant, along with novel structural and multifunctional characteristics, this study may be useful for different industrial and biotechnological applications.

Swift production of rhamnolipid biosurfactant, biopolymer and synthesis of biosurfactant-wrapped silver nanoparticles and its enhanced oil recovery.

Microbial enhanced oil recovery (MEOR) is a kind of enhanced oil recovery (EOR) development, often used as a tertiary stage where oil recovery is no longer possible utilizing primary and secondary conventional techniques. Among a few potential natural operators valuable for MEOR, biosurfactants, biopolymers and biosurfactant based nanoparticles assume key jobs. Biosurfactant which are produced by microorganisms’ act as are surface active agents that can be used as an alternative to chemically synthesized surfactants. Pseudomonas aeruginosa TEN01, a gram-negative bacterium isolated from the petroleum industry is a potential biosurfactant (Rhamnolipid) producer using cassava waste as the substrate. This work focuses on production and characterization of rhamnolipid from P. aeruginosa TEN01 and its use in enhanced oil recovery. The effectiveness of Chitosan that is deacetylated form of chitin which is a biopolymer that provides density and viscosity to the fluids is not known in enhanced oil recovery yet and so it is studied. Moreover, the fabrication of biosurfactant-mediated silver nanocrystals and its application in enhanced oil recovery is also studied. Sand-Pack column was constructed and the mechanism of oil recovery in the column was studied. While incubating the crude oil containing sand packed column with Biosurfactant-biopolymer and brine flooding in the ratio of 1:2, and Biosurfactant incubation - flooding with 3 g/l of biopolymer was found to be 34.28% and 44.5% respectively. The biosurfactant based silver nanoparticles are non-toxic and have better stability when compared to chemically synthesized silver nanoparticles. The oil recovery percentage by chemical based Ag NPs and biosurfactant based Ag NPs are 14.94% and 14.28% respectively.