微生物采油技术及其应用

介绍了微生物采油技术方法、菌种和营养液选择、油藏筛选标准、作用机理及矿场应用。     

Characterizations of surfactant synthesized from Jatropha oil and its application in enhanced oil recovery

Surfactants are frequently used in chemical enhanced oil recovery (EOR) as it reduces the interfacial tension (IFT) to an ultra‐low value and also alter the wettability of oil‐wet rock, which are important mechanisms for EOR. However, most of the commercial surfactants used in chemical EOR are very expensive. In view of that an attempt has been made to synthesis an anionic surfactant from non‐edible Jatropha oil for its application in EOR. Synthesized surfactant was characterized by FTIR, NMR, dynamic light scattering, thermogravimeter analyser, FESEM, and EDX analysis. Thermal degradability study of the surfactant shows no significant loss till the conventional reservoir temperature. The ability of the surfactant for its use in chemical EOR has been tested by measuring its physicochemical properties, viz., reduction of surface tension, IFT and wettability alteration. The surfactant solution shows a surface tension value of 31.6 mN/m at its critical micelle concentration (CMC). An ultra‐low IFT of 0.0917 mN/m is obtained at CMC of surfactant solution, which is further reduced to 0.00108 mN/m at optimum salinity. The synthesized surfactant alters the oil‐wet quartz surface to water‐wet which favors enhanced recovery of oil. Flooding experiments were conducted with surfactant slugs with different concentrations. Encouraging results with additional recovery more than 25% of original oil in place above the conventional water flooding have been observed. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2731–2741, 2017     

Purification and characterization of a cold-active protease from psychrotrophic Serratia marcescens AP3801

Protease activity was detected in the culture medium of Serratia marcescens AP3801 grown at 10°C, which was isolated from soil collected from the top of a mountain. The enzyme, designated as CP-58 protease, was purified to homogeneity from the culture broth by ion exchange and gel filtration chromatographies. The molecular mass of the protease was 58 kDa, and its isoelectric point was close to 6.0. Maximal activity toward azocasein was observed at 40°C and from pH 6.5 to 8.0. The activity was strongly inhibited by 1,10-phenanthroline, suggesting that the enzyme is a metalloprotease. The N-terminal amino acid sequence was Ser-Leu-Asn-Gly-Lys-Thr-Asn-Gly-Trp-Asp-Ser-Val-Asn-Asp-Leu-Leu-Asn-Tyr-His-Asn-Arg-Gly-Asn (or Asp)-Gly-Thr-Ile-Asn-Asn-Lys-Pro-Ser-Phe-Asp-Ile-Ala. A search through databases for sequence homology aligned CP-58 protease with metalloprotease. The result of the cleavage pattern of oxidized insulin B-chain suggests that CP-58 protease has a broader specificity than other proteases against the peptide substrate.     

Production of sophorose lipids byTorulopsis bombicola from safflower oil and glucose

The production of sophorose lipids increased with increasing concentrations of both safflower oil and glucose, and was profoundly influenced by the concentration of yeast extract. A high concentration of sophorose lipids (about 135 g/L) was obtained (in a 1-L Bellco stirred reactor) when the medium consisted of 10% glucose, 10.5% safflower oil, 0.1% urea, and 0.25–0.3% yeast extract. A similar yield of sophorose lipids also was obtained in a 20-L bioreactor. About 50% of the apolar sophorose lipid 1′,4″-lactone 6′,6″-diacetate (SL-1) was found in the mixture of sophorose lipids produced under these conditions.     

Polyacrylamide obtained by plasma-induced polymerization for a possible application in enhanced oil recovery

Summary Ultrahigh molecular weight polyacrylamides (PAAM) were obtained by plasma-induced polymerization in water solutions. The influenceof monomer concentration, sealing pressure, initiation time and post polymerization period on polymer yield and molecular weight were investigated. The viscosity and “screen factor” measurements, as well as the thermally stimulated depolarization currents spectroscopic data of the synthesized polymers, indicate good properties as efficient viscosity modifiers in displacement of fluids for enhance oil recovery (EOR). Received: 18 March 1998/Revised version: 21 April 1998/Accepted: 24 April 1998     

Physical and chemical properties of trans-free fats produced by chemical interesterification of vegetable oil blends

Fat blends, formulated by mixing a highly saturated fat (palm stearin or fully hydrogenated soybean oil) with a native vegetable oil (soybean oil) in different ratios from 10:90 to 75:25 (wt%), were subjected to chemical interesterification reactions on laboratory scale (0.2% sodium methoxide catalyst, time=90 min, temperature=90°C). Starting and interesterified blends were investigated for triglyceride composition, solid fat content, free fatty acid content, and trans fatty acid (TFA) levels. Obtained values were compared to those of low- and high-trans commercial food fats. The interesterified blends with 30–50% of hard stock had plasticity curves in the range of commercial shortenings and stick-type margarines, while interesterified blends with 20% hard stock were suitable for use in soft tubtype margarines. Confectionery fat basestocks could be prepared from interesterified fat blends with 40% palm stearin or 25% fully hydrogenated soybean oil. TFA levels of interesterified blends were low (0.1%) compared to 1.3–12.1% in commercial food fats. Presented at the 88th AOCS Annual Meeting and Expo, May 11–14, 1997, Seattle, Washington.     

Allelochemics produced by the hydrophyteMyriophyllum spicatum affecting mosquitoes and midges

An extract of the hydrophyteMyriophyllum spicatum L. was found to be toxic to first- and fourth-instar larvae of the mosquitoes,Culex quinquefasciatus Say,Culex tarsalis Coquillett,Culiseta incidens (Thomson),Aedes aegypti L., and chironomid midges in the laboratory. When first-stage larvae were exposed to the extract, the lowest concentration (6.4 mg extract/100 ml H₂O) produced 86,60, and 48% mortality inC. incidens, C. quinquefasciatus, andA. aegypti, respectively. Higher concentrations caused 100% mortality in both first and fourth instars (63.75 mg/100 ml H₂O or more). In general, the biocidal activity of the extract was found to be similar when first- and fourth-stage larvae were exposed. Some mortality in the successive pupal and adult stages was observed when fourth-stage larvae were exposed to the extract, but mortality occurred only in the various larval instars when first instars were exposed. Among the chironomids,Tanytarsus spp. was more tolerant to the extract thanChironomus spp. In addition to the biocidal activity against immature mosquitoes, the extract was found to show a unique activity acting as an attractant to both sexes of adultC. quinquefasciatus andA. aegypti. The response elicited inA. aegypti appeared to be somewhat higher than that inC. quinquefasciatus. In general, the percentage of males responding to water treated with the extract was higher than that of the females. The extract at higher concentrations seemed to show some repellency at the outset to both species, but induced positive responses later on.     

Utilization of molasses for biosurfactant production by two Bacillus strains at thermophilic conditions

Traditionally, biosurfactants have been produced from hydrocarbons. Some possible substitutes for microbial growth and biosurfactant production include urban wastes, peat hydrolysate, and agro-industrial by-products. Molasses, a nonconventional substrate (agro-industrial by-product) can also be used for biosurfactant production. It has been utilized by two strains of Bacillus subtilis (MTCC 2423 and MTCC1427) for biosurfactant production and growth at 45°C. As a result of biosurfactant accumulation, the surface tension of the medium was lowered to 29 and 31 dynes/cm by the two strains, respectively. This is the first report of biosurfactant production by strains of B. subtilis at 45°C. Potential application of the biosurfactant in microbial enhanced oil recovery is also presented.     

Ultra-rapid synthesis of syngas by the catalytic reforming of methane enhanced byin-situ heat supply through combustion

Development in highly active catalysts for the reforming of methane with CO₂ and partial oxidation of methane was conducted to produce hydrogen and carbon monoxide with high reaction rates. An Ni-based four-components catalyst, Ni-Ce₂O₃-Pt-Rh, supported on an alumina wash-coated ceramic fiber in a plate shape was suitable for the objective reaction. By combining the catalytic combustion of ethane or propane, methane conversion was markedly enhanced, and a high space-time yield of syngas, 25,000 mol/l·h was obtained at a catalyst temperature of 700 ‡C or furnace temperature of 500 ‡C. The extraordinary high space-time yield of syngas was also confirmed even under the very rapid flow rate conditions as a contact time of 3 m-sec by using a monolithic shape of catalyst bed without back pressure.     

Selective ion-exchange in MAPO-36 and its application in toluene disproportionation

MAPO-36 was synthesized hydrothermally by isomorphic substitution of Mg²⁺ in the framework of AlPO-36 and ion-exchanged with Fe³⁺, Zn²⁺, La³⁺ and Ce³⁺ by wet method. The materials were characterized by XRD, TGA, TPD (ammonia) and SEM-EDX. XRD revealed absence of structural degradation after ion-exchange. TPD (ammonia) showed selective ion-exchange of strong acid sites in ion-exchanged MAPO-36. The weight loss around 550 °C in TGA for Fe, La and CeMAPO-36 suggested conversion of M(OH)₂⁺ to MO⁺. Toluene disproportionation was carried over all catalysts in which diphenyl methane derivative was suggested to be the principle intermediate in the formation of p-xylene and other products. The time on stream study showed exclusive formation of p-xylene after 6 h.     

Application of a novel cationic starch in enhanced oil recovery and its adsorption properties

We report a preparation of water-soluble cationic starch and its application as an oil-displacing agent in chemical enhanced oil recovery. The singular sand-pack core-flood tests provide experimental evidence that the injection of the modified starch after the conventional water flooding can significantly enhance oil recovery and effectively reduce water-cut. To discuss the proposed oil-displacement mechanism of this cationic starch solution, its static and dynamic adsorption properties were also presented in this paper.     

Corrosion behaviour of AISI 304 stainless steel in presence of a biosurfactant produced by Pseudomonas fluorescens

Under certain conditions, some microorganisms are able to synthesize surface active compounds called biosurfactants (BS), which reduce the surface tension of water. BS characteristics depend on which microorganism produce them and therefore, on the microorganism culture conditions (temperature, pH, C, N-source,…). Numerous applications are known for these biomolecules, such as cleaning, bioremediation, and their use as a detergent, or in cosmetic formulations.Recently, a large amount of literature has been edited on the influence of BS on the interactions between pathogenic bacteria and inert surfaces. It has been shown that the modifications of surface properties by the adsorption of BS can reduce microbial adhesion.Some other studies on chemical surfactants have shown that the adsorption of surface-active compounds plays a major role in corrosion; they are indeed used as an interesting corrosion inhibition tool. Therefore, it seems very interesting to study the impact of BS as environment-friendly (since biological and biodegradable) corrosion inhibitors.In the present work, an attempt was made to study the corrosion behaviour of AISI 304 stainless steel in presence of BS produced by a Gram-negative bacteria, Pseudomonas fluorescens (Pf495). Corrosion tests were achieved on several surface oxidation states. The surface morphology of the corroded specimens was investigated using SEM.     

Liquid-phase p-t-butyltoluene autoxidation enhanced by electrochemistry: Activation of the catalytic effect of cobalt acetate

The autoxidation of p-t-butyltoluene (TBT) at 80 °C in the liquid phase is carried out with an initial mixture of cobalt(III) and cobalt(II) acetate in an acetic acid solution. The autoxidation kinetics of TBT is appreciably accelerated by electrolysis with a anodic current density of 62.5 A m^–2. The electrolysis increases the concentration of cobalt(III) acetate, the actual catalyst of the autoxidation reaction. The end product of oxidation is p-t-butylbenzoic acid (TBBA). p-t-Butylbenzaldehyde (TBBZ) is an intermediary whose concentration passes through a maximum. The oxidation experiments with TBT were performed with total cobalt acetate concentrations ranging from 0.0188 to 0.169 mol dm^–3. An increase in total cobalt acetate concentration favours the electrochemical regeneration of Co^III and slightly improves the TBBZ selectivity. The duration of TBT oxidation into TBBA is reduced by a factor of 5 compared with a reaction without electrolysis.     

Immobilization of <Emphasis Type="Italic">Candida rugosa</Emphasis> lipase by sol-gel entrapment and its application in the hydrolysis of soybean oil

Immobilization of lipase AY from Candida rugosa by entrapment within a chemically inert hydrophobic sol-gel support was studied. The gel-entrapped lipase was prepared by polycondensation of hydrolyzed tetramethoxysilane and isobutyltrimethoxysilane. Certain modifications were incorporated into the conventional immobilization procedure, including the use of glucose as additive and the application of vacuum during the drying and aging stages. The activity and thermostability of immobilized enzyme were subsequently determined in hydrolyzing soybean oil. Hydrolysis results showed more than 95 mol% of the theoretical yield for the formation of FF after 1 h of reaction at 40°C. The level of FFA was 3.3 times greater than that seen when an immobilized enzyme was prepared by the conventional sol-gel process. The immobilized enzyme retained most of its hydrolytic activity compared to the free enzyme and kept more than 95% activity after 120 h of incubation at 40°C, whereas the free enzyme lost 67% of its activity after 24 h of incubation and almost all of its activity after 96 h of incubation at 40°C. The immobilized enzyme also proved to be very stable, as it retained more than 90% of the initial activity after 16 one-hour reactions. Surface characterization studies suggested that the enzyme-containing sol-gel particles have amorphous morphology and are void of micro/meso pores.     

Isolation of erucic acid from rapeseed oil by lipase-catalyzed hydrolysis

Three lipases were compared for their ability to hydrolyze high erucic acid rapeseed oil, with the objective of concentrating the erucic acid in a single glyceride fraction. Lipase fromPseudomonas cepacia released all fatty acids rapidly and did not result in selective distribution of erucic acid.Geotrichum candidum lipase released C20 and C22 fatty acids extremely slowly, resulting in their accumulation in the di- and triglyceride fractions. Less than 2% of the total erucic acid was found in the free fatty acid (FFA) fraction. Lipase fromCandida rugosa released erucic acid more slowly than C20 and C18 fatty acids at 35°C but only resulted in a limited accumulation of the erucic acid in the di- and triglyceride fractions. However, when hydrolysis catalyzed byC. rugosa lipase was carried out below 20°C, the reaction mixture solidified and was composed solely of FFAs and diglycerides. The diglyceride fraction contained approximately 95% erucic acid while about 20% of the total erucic acid was found in the FFA fraction. It is concluded that hydrolysis at low temperature withC. rugosa lipase results in a higher purity of erucic acid in the glyceride fraction than can be obtained withG. candidum lipase, but with considerable loss of erucic acid to the FFA fraction.     

Synthesis of superacidic mesoporous alumina and its application in the dehydration of glycerol

Superacid ZrO₂/SO₄²⁻ (SZ) was supported on mesoporous alumina (MA) to synthesize a novel superacid catalyst (SZMAP) with high active surface area. The synthesized catalyst was characterized by both physical and chemical methods, including XRD, BET, NH₃-TPD and TEM. The prepared superacidic mesoporous alumina (SZMAP) showed typical gamma-alumina phase patterns and uniform mesoporous structures with a regular channel arrangement. NH₃-TPD analysis indicated that SZMAP has superacidic characteristics. The SZMAP catalyst was used in the dehydration of glycerol to acrolein. Results showed that SZMAP showed much higher catalytic activity than the bulk superacid, ZrO₂/SO₄²⁻ (SZ), and MA due to the high dispersion of active SZ molecules, which results from a large surface area and uniform mesopores of mesoporous alumina.     

Effects of allelopathic substances produced by asparagus on incidence and severity of asparagus decline due toFusarium crown rot

The effects of toxic components isolated from asparagus tissue onFusarium spp. and other soil microorganisms and their effects on the susceptibility of asparagus toFusarium crown rot was investigated to determine what role allelopathic substances may play in the asparagus ecosystem and in asparagus crown rot decline. Dried sterilized asparagus crown and root tissues were incorporated into pots of 3-month-old asparagus seedlings with and withoutFusarium inoculum. Root tissue alone and treatments in which crown and root tissues were combined with theFusarium inoculum showed significant reduction of plant growth over nontreated controls. Root and crown tissues were partitioned with polar and nonpolar solvents and bioassayed on pregerminated asparagus and cress seeds. Inhibition of radicle growth was confined to the polar fractions. Further separation with paper chromatography gave several fractions that were inhibitory to radish, cress, tomato seed germination as well as inhibitory to growth of pregerminated asparagus seeds. Crude extracts from roots and crown residues were bioassayed on many different fungal isolates on Petri plates and were found to inhibit the growth of oomycetous fungi. Extracts from the roots were found to be more active than extracts from other portions of the asparagus plants.     

Male-specific EAD active compounds produced by female European chafer Rhizotrogus majalis (Razoumowsky)

Chemical investigation of a fmale balloon-like organ of the European chafer, Rhizotrogus majalis (Razoumowsky), with GC-EAD has resulted in the identification of female-specific compounds, (R)-3- hydroxybutan-2-one, (2R,3R)-2,3-butanediol, and meso-2,3-butanediol that are specifically EAD-active with male antennae. No behavioral role for any of the EAD active compounds could be discerned with this species.