Molecular characterization of biosurfactant producing Bacillus cereus strain DRDU1 for its potential application in bioremediation and further EOR studies

Abstract

Environmental pollution by crude oil during petroleum exploration is a global issue of concern. It largely alters the physicochemical property of soil and water which makes them toxic for crops and aquatic organisms to survive. Bacillus cereus strain DRDU1 (Genbank accession no. KF273330.1) is an endospore forming potential hydrocarbon degrader which was isolated from an automobile engine. The isolate could achieve up to 96 and 84% kerosene and crude oil degradation with respective cfu of (6.3?±?2.31)?×?10⁹ and (13.67?±?2.52)?×?10⁸ cells/mL. On the other hand it also showed its potential to degrade 74 and 67% of kerosene and crude oil in nitrate (N) and phosphate (P) deficient media with corresponding cfu (10?±?1.73)?×?10⁸ and (6?±?2.65)?×?10⁶ cells/mL. This indicates its potential to survive under nutrient stress condition. The strain was reported to be capable of producing biosurfactant which may play role in petroleum biodegradation and may be a potential tool for Microbial Enhanced Oil Recovery (MEOR) studies in future. Herein the presence of sfp gene in the isolate was confirmed which may be responsible for its ability to synthesize biosurfactant for hydrocarbon degradation and also for its stress tolerant potential. It was further characterized and the hypothetical protein sequence encoded by this gene is also proposed.     

A New Technique for Measurement of Oil Biodegradation

Abstract

An active strain of anaerobic thermophilic bacteria was isolated from the environment of the United Arab Emirates. The strain, identified as Bacillus species, consists of two types—round and rod-shaped bacteria. This project studied the possibility of using these two types of bacteria for biodegradation of oil under elevated temperature conditions using a new method of measurement. Chemical and physical techniques were used previously to estimate the degradation rate of oil by microbes. In this project, a technique is was used to provide more accurate and reliable measurements. Visual inspection and measurements of oil drop size as a function of time were conducted. A computer image analyzer was used in this study to track bacterial growth and capacity to survive under different environmental conditions.

The temperature of the studied systems varied between 25°C and 70°C, and salt (sodium chloride (NaCl)) concentration varied between 0 and 50,000 ppm NaCl. The temperatures were selected to include typical sea water and reservoir temperatures in the Persian Gulf region. The average bacterial concentration used in this study was 182 × 10³ cells/mL. Experimental results indicated that the bacteria have the capacity to survive in saline and high temperature environments. The maximum oil degradation was observed at 70°C for all tested salinities. The degradation rate can be maximized by lowering the salinity and increasing the temperature of the studied systems. At a high temperature of 70°C, bacterial growth tends to improve at a low salt concentration, with a maximum oil degradation rate obtained at 10,000 ppm NaCl.     

THERMAL EFFECT ON THE PERMANENT VISCOSITY OF A SASKATCHEWAN HEAVY OIL

ABSTRACT

Future energy demands will likely cause increased activity towards the recovery of heavy oil using non-conventional means. Most non-conventional attempts to recover Saskatchewan's heavy oil resources have utilized thermal techniques.

This report discusses the permanent viscosity changes which occur when heavy oil.is subjected to thermal processes from 220 to 425°C. It was observed that under closed operating conditions, the oil viscosity drops in a manner which can be modeled by a first order, kinetic reaction model. The rate constant for this reaction varied from 0.3 × 10^?3 to 6.0 × 10^?3 h^?1 depending on temperature and the assumed molecular weights of the model components. These findings closely parallel earlier results.

Experimental observations on thermal effects during opened operating conditions indicate a dramatic and rapid rise In the remaining crude oil viscosity. The oil was observed to increase its permanent absolute viscosity by a factor as high as 21 times its original absolute viscosity. The single product, first order kinetic model was not capable of predicting this rise in oil viscosity. A simple, two product, first order kinetic model was developed and found to fit the data satisfactorily with a rate constant of 0.6 h^?1 for heavy product formation and a rate constant of 0.03?h^?1 for light product formation at 275°C.     

Modification and characterization of NaY molecular sieve by Cr3+ and its adsorptive denitrogenation from model fuel

Abstract

The CrY, which was modified by Cr³+ from NaY, was confirmed by characterization with FT-IR, XRD, N₂ adsorption-desorption, and it was used to adsorb quinoline from model fuel. The suitable modification conditions were modified twice by 0.5?mol/L cobalt nitrate solution at 40?°C. The FT-IR spectra indicated the disappearance of 1147?cm^?1 peak and the blue shift of 1024?cm^?1, implying that Cr³+ had exchanged Na⁺ and successfully incorporated into the framework of NaY. The static denitrogenation experimental results indicated that the adsorption between quinoline and CrY was the coordination adsorption and π complex adsorption. The suitable conditions were 30?min at room temperature and the adsorption temperature had minor effect on denitrogenation. The kinetic model of CrY adsorbing quinoline belonged to Langmuir and Freundlich adsorption model.     

Effect of Microbial Count of P. aeruginosa on Biodegradation of Crude Oil Contaminated Water

Abstract

The effect of microbial count of Pseudomonas aeruginosa bacteria amended with 20 g of nitrogen-phosphorous-potassium (NPK) fertilizer (15:15:15) on the biodegradation of crude oil-contaminated water was studied. Four samples, S ₁, S ₂, S ₃, and S ₄, with equal crude oil pollution load were inoculated with, 1 × 10⁵ cfu, 2 × 10⁵ cfu, 4 × 10⁵ cfu and 8 × 10⁵ cfu of P. aeruginosa respectively, and 20 g of NPK (15:15:15) fertilizer. The control sample, Sc, had only 8 × 10⁵ cfu P. aeruginosa and no fertilizer.

Parameters such as oil and grease content, pH, BOD, COD, and turbidity were monitored over a nine-week period. At the end of the biodegradation period, a high percentage of oil and grease content was removed. The value reduced from 185.0 to 41.50 mg/L, 24.6 mg/L, 20.5 mg/L, 13.2 mg/L, 10.9 mg/L for S _c , S ₁, S ₂, S ₃, and S ₄ respectively. There was also a drop in BOD, COD, turbidity, and pH of the samples under consideration. The S ₄ sample had the highest reduction in both BOD and COD values. The initial value dropped from 82.0 to 27.5 mg/L and 158.4 to 64.8 mg/L for the BOD and COD, respectively. These values obtained fall within the Federal Environmental Protection Agency (FEPA) limits. The oil and grease content for S ₄ sample was also reduced from 185 mg/L to 9.95 mg/L, while the pH value for this same sample, S ₄, was 6.60 after the nine-week period of investigation.     

Petroleum Sulfonates as Oil Displacement Agents and Application to Gudao Oil Field

Abstract

In terms of the condition of injection of water after polymer flooding of the Gudao oil field (Shengli, China), the following water quickly broke though the bank to the production wells, while most of residual oil remained in the formation. To solve the problem, two types of petroleum sulfonates made in China were selected to form an oil displacement agent (ODA) solution. The petroleum sulfonate available for crude oil from the Gudao oil field with the ultra-low interfacial tension can be found by drawing an oil/water interfacial tension contour diagram. The results show that the interfacial tension can be lower than 3.6 × 10^?4 mN/m when the active agent is contained with 0.25% Kelamayi petroleum sulfonate (KPS) + 0.225% Anqing petroleum sulfonate (APS) and if the agent reduces water resistance by entering the tiny pore to improve sweep coefficient and oil displacement efficiency. The polymer has no influence on the balanced value of interfacial tension but delays the interfacial tension to reach the balance. Pouring 0.3 pore volume (PV) high-efficient ODA into reservoir can improve 17% oil recovery (OR). Synergistic effects of two types of petroleum sulfonate with low cost to enhance OR will have an excellent prospect for enhanced oil recovery (EOR).     

Study on paraffin wax degrading ability of Pseudomonas nitroreducens isolated from oil wells of Gujarat,India

Microbial remediation is an efficient method of removing paraffin wax from oil wells and pipelines and is found to be environment friendly and economical. In this study, a potential paraffin wax degrading bacterial strain was isolated from oil wells of Gujarat and was identified as Pseudomonas nitroreducens by 16S rRNA sequencing. Pseudomonas nitroreducens showed 100% utilization of heneicosane, 79.74% utilization of pentacosane and 72.50% utilization of triacontane, the major components of paraffin wax in 8 days at 37°C. Pseudomonas nitroreducens degraded 70% of paraffinic crude oil in 10 days at 37°C. The probable end products formed after degradation of eicosane and heneicosane by Pseudomonas nitroreducens were analysed by Mass Spectrum. The above results proving isolate as a potential candidate for degradation of paraffin wax in oil wells.     

Biodegradation of Used Engine Oil by a Methylotrophic Bacterium,Methylobacterium Mesophilicum Isolated from Tropical Hydrocarbon-contaminated Soil

A Gram-negative facultatively methylotrophic bacterium putatively identified as Methylobacterium mesophilicum strain RD1 displayed extensive degradative ability on used engine oil (SAE 40W) in liquid cultures. The rate of degradation of used engine oil (1274.85 mg L^?1) by the isolate, for the first 12 days and the last 9 days were 65 and 40 mg L^?1 d^?1, respectively. Gas chromatographic (GC) analyses of residual used engine oil revealed that 61.2% and 89.5% of the initial concentration of the used engine oil were degraded within 12 and 21 days. GC fingerprints of the used engine oil after 12 days of incubation showed total disappearance of C₁₅, C₂₃, C₂₄, C₂₅, and C₂₆ hydrocarbon fractions as well as drastic reductions of C₁₃, C₁₄, C₁₆, and PAHs fractions such as C₁₉-Anthracene and C₂₂-Pyrene. At the end of 21 days’ incubation, total disappearance of C₁₇-pristane, C₂₂-pyrene, one of the C₁₉-anthracene, and significant reduction of C₁₈-phytane (96.8%) fractions were observed. In addition, less than 10% of Day 0 values of medium fraction ranges C₁₃, C₁₄, and C₁₆ were discernible after 21 days. This study has established the potential of Methylobacterium mesophilicum strain RD1 in degradation of aliphatic, aromatic, and branched alkane components of used engine oils.     

A Comprehensive Evaluation of High Viscous Crude Oil from Shuguang No. 1 Zone of Liaohe Oil Field

Abstract

The high viscous crude oil from Shuguang No. 1 zone of Liaohe oil field has the characteristics of high density (ρ ₂₀ = 0.9977 g cm^?3), great viscosity (ν ₁₀₀ = 1223.9 mm² s^?1) and high pour point (48°C), which are similar to those of the residue distillation of general crude oils. It contains no gasoline distillation and the diesel oil fraction yield is just 7.19%. It is often used as fuels after emulsification. But this oil is so vicious that it cannot be atomized uniformly and burned fully. In order to make full use of it, this kind of high viscous crude oil has been evaluated comprehensively and the properties of its various distillations are analyzed respectively. The results indicate that this crude oil contains less wax, but more resins and asphaltene, which belongs to low-sulfur naphthene-base crude oils and it is the suitable material to produce high-quality paving asphalt. Based on its characteristics, the optimum processing scheme is put forward and the high-quality paving asphalt is produced by using the distillation higher than 350°C.     

Microbial treatment of waxy crude oil for mitigating wax precipitation and improving liquidity

The wax deposition of crude oil during transportation reduces the inner diameter, blocks the pipeline, and eventually increases the cost of petroleum production. This study reports a paraffin-degrading bacterial strain DG2 isolated from petroleum-contaminated soil. The effect of this strain on the removal of paraffin in crude oil was investigated. DG2, identified as Pseudomonas, produced biosurfactant that reduced the surface tension to 35.7?mN/m^?1 and exhibited high emulsification activity. Results of gas chromatography–mass spectrometry analysis of the waxy crude oil treated by DG2 showed decreased heavy hydrocarbon fractions (C25 and C32). The degradation test revealed that DG2 reduced the wax appearance temperature by 4.16?°C and the viscosity by 23% of the waxy crude oil. These findings indicate that paraffin-degradation strain DG2 may be used for effective paraffin biodegradation.     

WETTABILITY ALTERATION AND IMPROVED CRUDE OIL RECOVERY WITH ACETONE

Abstract

Laboratory studies are presented in this work wherein oil recovery can be substantially increased by injecting a low volume fraction of acetone along with brine during waterflooding. 10% of acetone used in flooding water could displace 13.2% of the original oil in place from a sand pack as compared to only 3.0% by brine without acetone. This volume fraction of acetone lowered the contact angle from 90^° to 42^°. Salinity was observed to have only slight effect on displacement efficiency.     

EFFECTS OF HYDROTREATING COKER LIGHT GAS OIL ON FUEL QUALITY

ABSTRACT

Coker light gas oil (LGO) derived from Athabasca bitumen was hydrotreated in a fixed bed reactor using two commercial NiO-MoO₃/Al₂0₃ catalysts. The effect of temperature on product quality was investigated in a pilot plant between 330 and 390 °C at 12.4 MPa, space velocity of 0.5 Ir1 and 700 liter of hydrogen per liter of coker LGO (L/L). The product quality was monitored by ^I3C NMR spectroscopy, elemental analysis, density and distillation techniques.

The data showed that coker LGO can be hydrotreated using nickel-molybdenum catalysts at 350 °C, 0.5 h¹, 12.4 MPa and 700 L/L to meet the diesel product specifications, namely, 0.5 wt % sulfur, 20% aromatics and cetane index of 40. The cetane index improvement and aromatic saturation, which are affected by thermodynamic equilibrium at temperature higher than 370?°C, could reach 29 and 86% respectively. The cetane improvement was attributed to aromatic saturation and hydrocracking with hydrogen consumption ranging from 215-340 L/L. The Ketjenfine KF-840 catalyst was found slightly better performance than Procatalyse HR-348 catalyst.     

THE STUDY OF PRODUCING HEAVY TRAFFIC ASPHALT BY USING THE HIGH VISCOUS CRUDE FROM NO.l SHUGUANG ZONE OF LIAOHE OIL FIELD

ABSTRACT

The characteristics of the high viscous crude from No. 1 Shuguang Zone of Liaohe Oil Field are similar to those of residue distillates of general crude such as high density(ρ ₂₀=0·9977 g.cm^-3),high viscidity υ ₁₀₀= 1223·9 mm².s-¹) and high carbon/hydrogen ratio. This oil contains less wax, but rich in resin and asphalt, which belongs to low sulfur naphthene-base crude oil and can be used as feedstock to produce high paving asphalt. But now it is used as fuel after emulsificating. In order to make full use of this oil and resolve the problem of paving asphalt demand-supply, various paving asphalts conforming to GB50092-96 standard were produced by blending vacuum residue of the high viscous crude from No.l Shuguang Zone of Liaohe Oil Field and waste oil which is rich in aromatics and poor in wax. The laboratory test results show that modified paving asphalts have good low-temperature properties and antiaging feature.     

Shear strengthening viscosity and shear-rate-dependent modulus model for a Shengli crude oil

The steady shear viscosity of a Shengli waxy crude oil at the temperature of 3°C to 4°C, higher than its gel point, was measured by using a parallel-plate rheometer, which shows a shear thickening behavior in the shear rate range of 10^?2–10^?1 s^?1. A spectrum model proposed in our previous work was modified here by considering the modulus change in the spectra, which could be caused by a shear-induced varying internal structure in the crude oil. The shear strengthening viscosity of the Shengli crude oil can be described well by the changing-spectrum viscosity model.     

ESMAOC AS POUR POINT DEPRESSANT FOR CRUDE OIL AND HEAVY OIL PRODUCTS

ABSTRACT

The synthesis of esterified copolymer of maleic anhydride/olefines mixture and its effect as pour point depressant for crude oil and heavy oil products were studied. The optimum ratio of the maleic anhydride/mixed a-olefines for the synthesis of EsMAOC is 1:6.29. On Daqing crude oil, the adequate addition amount of EsMAOC is 0·5–1.0 wt% when the decrease of pour point can reach to 8–10°C. To Anshan heavy diesel oil No. 20, the data are 1·0 wt%, 13°C respectively.     

A Highly Efficient Decalcification Agent Applied in the Crude Oil of Liaohe

Abstract

A highly efficient decalcification agent without phosphorus matter or metal included was developed for Liaohe crude oil, and calcium contents in the crude before and after decalcification were analyzed by atomic absorption spectrometry. Influences of agent-to-calcium ratio, water injection amount, reaction temperature, and reaction time were studied. The results showed that at an agent-to-calcium ratio of 0.6, water injection ratio of 10%, reaction temperature of 90°C, and reaction time of 5 min the decalcification rate of Liaohe can reach more than 90%.     

Optimization of biodegradation of polycyclic aromatic sulfur heterocycles in soil using response surface methodology

Abstract

This paper uses response surface methodology based on the Box-Behnken design to investigate the influence of substrate concentration, inoculation quantity and temperature on the biodegradation of polycyclic aromatic sulfur hydrocarbons in oil-contaminated soil by Pseudomonas sp. LKY-5. Substrate concentration is identified as the most important factor through the analysis of variance. The maximum degradation of PASHs can be achieved at the conditions of substrate concentration of 75.77?ml/kg, inoculation quantity of 20.4% and temperature of 30?°C.     

Degradation of fumonisin B1 by cinnamon essential oil

Fumonisins are group of mycotoxins produced mainly by Fusarium verticillioides and Fusarium proliferatum. They frequently contaminate corn and corn based products, and cause several diseases in humans and animals. Fumonisin B₁ (FB₁) is the most prevalent fumonisin and is highly toxic to human and animal. The essential oils from plants offer a hope in the prevention and detoxification of these mycotoxins. The present study investigates the degradation effect of cinnamon, citral, Litsea cubeba, clove, eucalyptus, anise, spearmint and camphor oils on FB₁. The degradation level of FB₁ was determined by ELISA. Cinnamon oil proves to be effective essential oil in reducing FB₁, followed by citral, eugenol oil, eucalyptus oil, anise oil and camphor oil. The effects of incubation time, and temperature with respect to the concentration of cinnamon oil on their degradation effect on FB₁ by cinnamon oil were investigated. Results showed that at 120 h time with the 280 μg/ml concentration of cinnamon oil, under 30 °C is optimal for FB₁ reduction. Under optimal condition, FB₁ was reduced from 15.03 to 0.89 μg/ml (94.06%). Cinnamon oil could be a promising candidate in the detoxification and control of FB₁ in corn based products.     

KINETICS OF CORN COB CHAR GASIFICATION IN CARBON DIOXIDE

ABSTRACT

The Reactivity of corn cob char in CO₂ has been studied on a thermogravimetric balance to develop a rate equation for the design of biomass gasifiers operating on corn cob char. Experiments in the range of 650-1000^°C were conducted with cylindrical shaped pellets of 1 cm diameter having L/D=l. The average porosity of the pellets was 0.5. It was observed that the rate of the CO₂/char reaction decreased with increase in temperature from 650-750^°C and then increased with temperature upto 1000^°C.

The data obtained at temperatures 750^°C and above has been used to determine a rate equation for char gasification. It has been found that the reaction proceeds according to the Sharp Interface Model (SIM) with a first order chemical reaction as the rate controlling step. The activation energy is found to be 40 Kcal/mole with frequency factor being 1.2 × 10⁷ mm/sec. Analysis of the data obtained for the decreasing reaction rate regime (650-750^°C) indicates that the change in the ash structure result in this kind of behavior.     

Impact sensitivity of nitroglycerin

Abstract

The impact sensitivity of liquid nitroglycerin, 50% initiation level, was observed to be near 1.8 kg?cm or 3.3 × 10³ j/m². The impact sensitivity of solid nitroglycerin, 50% initiation level, was observed by extrapolation to be near 200 kg?cm or 4.4 × 10⁵ j/m². The impact sensitivity of a mixture of solid and liquid NG was observed to be comparable to solid NG at the two stimulus levels tested. Thus, the presence of solid nitroglycerin reduces the impact sensitivity of liquid nitroglycerin.

The 50% initiation level for Class A cyclo-tetra-methylenetetranitramine was observed to be near 150 kg?cm or 3.3 × 10⁵ j/m² using the same instrument.