烃降解菌株T7-2产生的生物乳化剂及其理化性质研究

从石油污染海域海底泥中筛选到的1株低温石油烃降解菌, 经鉴定为红平红球菌(Rhodococcus erythropolis), 命名为T7-2。该菌株能以十六烷为碳源代谢产生一种对柴油等烃类具良好乳化作用的生物乳化剂。研究表明, 该乳化剂主要由糖类、脂类和蛋白质组成, 其比例为55.43:31.24:12.65。进一步研究证实, 该乳化剂糖类的单糖组成为甘露糖和鼠李糖; 脂类由十碳、十二碳、十六碳及十八碳脂肪酸组成; 蛋白质由16种氨基酸构成。本文还对乳化剂的理化性质进行了分析, 发现它是一种性能稳定、乳化效率高、适应范围较为广泛的生物乳化剂, 对海洋污染生物修复及石油开采都具有潜在的应用价值。     

生物乳化剂产生菌及其产乳化剂条件初步研究*

从胜利油田原油污染土壤边分离得到一株能降解多种石油芳烃和烷烃且能产生物乳化剂的细菌Eml,经生理生化及16S rRNA基因序列分析鉴定为赤红球菌(Rhodococcus ruber)。对菌株Eml产生乳化剂的条件进行了研究,结果表明,该菌株在以正十六烷为碳源时能较快速产乳化剂,其最佳条件为：正十六烷10g/L,酵母抽提物1g/L,初始pH值为7,30℃下200r/min摇床培养。在此条件下,发酵ld后,培养液的表面张力即降到最低值,约30mN／m,而乳化能力达100％;乳化剂浓度则在第5d达到最大,为68倍的CMC;经初步研究该乳化剂为脂类物质。     

新型复合生物乳化剂的性质及其在多环芳烃降解中的作用

对一株能利用多种石油烃的Em1菌株产生的生物乳化剂 ,采用柱层析方法进行分离纯化 ,其表面活性组分存在于氯仿、甲醇、浓盐酸混合物 (V V V =5∶1∶0 0 1 )的洗脱液中 ,挥发洗脱溶剂即为纯化的生物乳化剂。该生物乳化剂可使蒸馏水的表面张力由 72mN m降至 30mN m ,其临界胶团浓度 (CMC)为 75mg L。它不含糖类、蛋白、中性脂、磷酸基团和α 氨基酸 ,采用红外光谱 (IR)、气质联用 (GC MS)和核磁共振 (NMR)测定其化学组成和结构 ,表明其主要由十六烷酸、脂肪醇类、酯类和脂肪酰胺类等组成 ,这些物质的协同作用是该生物乳化剂高表面活性的关键。该生物乳化剂可明显促进菌株对多环芳烃的降解作用 ,可将降解率提高 2 0 % ,其促进降解的机制主要是提高多环芳烃在水中的溶解度 ,平均可提高约 1 0倍的溶解度     

嗜热解烃菌DM-2产生的生物乳化剂

【目的】生物乳化剂是一类由微生物代谢产生的大分子生物表面活性物质,从胜利油田中1区N3块地层环境中筛选到一株能产生一种生物乳化剂的嗜热解烃菌DM-2,经鉴定为嗜热脂肪地芽孢杆菌(Geobacillus stearothermophilus),研究其产生的生物乳化剂的化学组成和理化性质。【方法】采用化学显色、红外光谱、高效液相色谱和氨基酸自动分析等方法确定乳化剂的化学组成;根据乳化剂在不同条件下的乳化指数(EI-24)确定其理化性质。【结果】菌株DM-2产生的乳化剂主要由多糖(71.4%,质量比)和蛋白(27.75%,质量比)组成,对柴油、苯、二甲苯和煤油等石油烃均有很好的乳化效果。理化性质分析显示它是一种耐高温、耐盐、耐酸碱的高效乳化剂。【结论】菌株DM-2产生的乳化剂是一种新型的生物乳化剂,在石油开采、原油集输、油罐清洗和石油污染治理等领域具有潜在的应用价值。     

喜热噬油芽胞杆菌产生的生物乳化剂的组成与性质

由喜热噬油芽胞杆菌(Geobacillus thermoleovorans str 5366T)以正十六烷为碳源 55 ℃培养的发酵液中分离获得了一种生物乳化剂,经鉴定为糖-肽-脂复合物.该乳化剂中糖、肽、脂和烃的含量分别为29.4%、15.8%和35.8%.利用肽水解结合氨基酸分析、糖醇乙酰化结合GC-MS、脂肪酸甲脂化结合GC-MS等技术手段鉴定乳化剂中糖主要为D-甘露糖;主要氨基酸为谷氨酸、天冬氨酸、丙氨酸;构成脂的主要脂肪酸为十六烷酸、十八烯酸和十八烷酸.该菌及其代谢产生的乳化剂乳化性能良好,具有高温条件下应用的潜力.     

微生物脂多糖的产生、分离及乳化性能

Acinetobacter sp．生长在醇类、植物油或正烷烃中能产生胞外脂多糖。探讨了此菌株产生胞外脂多糖的最佳条件,包括不同碳源．不同氨源,二价镁离子及添加抗菌素等对其产量的影响。脂多糖含量的测定采用了乳化比浊度的方法。研究表明,此胞外脂多糖具有明显的乳化性及乳化稳定性,是一种聚合的生物乳化剂。     

微生物脂多糖的产生、分离及乳化性能

Acinetobacter sp．生长在醇类、植物油或正烷烃中能产生胞外脂多糖。探讨了此菌株产生胞外脂多糖的最佳条件,包括不同碳源．不同氨源,二价镁离子及添加抗菌素等对其产量的影响。脂多糖含量的测定采用了乳化比浊度的方法。研究表明,此胞外脂多糖具有明显的乳化性及乳化稳定性,是一种聚合的生物乳化剂。     

一株石油烃降解菌的细胞疏水性及其乳化性质

【目的】从新疆油田石油污染土壤中分离到一株在25 °C条件下利用烃类产生生物表面活性剂的菌株红球菌(Rhodococcus sp.) HL-6, 对其菌体细胞疏水性及所产表面活性剂进行研究。【方法】通过细胞粘附性、表面张力及乳化活性测定对菌株所产表面活性剂进行性质研究。【结果】菌株HL-6在亲水性和疏水性基质中均能产生生物表面活性剂, 在疏水性基质中可以将培养液表面张力由初始的62.487 mN/m降到30.667 mN/m, 培养液在pH 6?9及NaCl浓度1%?5%范围内乳化效果良好, 在4 °C到55 °C范围内乳化效果均为100%, 菌株对柴油的耐受能力很高, 在30%柴油浓度下依然生长良好并且有44%的乳化活性。【结论】HL-6菌株的细胞表面具有很强的疏水性, 这有助于菌体细胞对烃类的摄取。该菌株能够利用烃类基质生产生物表面活性剂, 可以明显降低培养液表面张力并且对石油烃具有良好的乳化作用。说明菌株HL-6能够适应海洋滩涂石油污染的环境, 并可用于严重石油污染区域的生物修复。     

一种低温石油烃降解菌产生的烃类乳化剂

由于生物乳化剂在化工、环境、食品、农业等领域具有较大的应用潜力,早在上世纪60年代,国外同行就对生物乳化剂展开了研究,发现降解烃类的微生物能产生乳化剂.     

石油污染土壤堆制微生物降解研究

采用异位生物修复技术堆式堆制处理方法 ,对辽河油田原油污染土壤进行了生物修复处理研究 .处理工程设 4个处理料堆单元 ,每个处理单元长 118.5cm ,宽 6 5 .5cm ,高 12 .5cm .研究结果表明 ,当进行处理的石油污染土壤中石油烃总量为 5 .2 2 g·10 0 g-1土时 ,利用黄孢原毛平革菌 (Phanerochaetechrysospori um) ,经过 5 5d的运行 ,石油烃总量去除率达 5 4.2 % .堆制处理中影响污染土壤石油烃总量生物降解的主要变化因子为污染土壤的O2 和CO2 含量、降解石油烃微生物的数量、污染土壤pH的变化 .通过监测这些数据的变化 ,可直接反映该工程的处理石油污染土壤的效果 .本处理工程采用定期通风措施 ,操作简单、运行费用低廉 ,为石油污染土壤生物修复实用化提供了一种简单易行的污染土壤清洁技术 .     

Characterization and emulsifying property of a novel bioemulsifier by Aeribacillus pallidus YM-1

Aims: Biosurfactants and bioemulsifiers commonly have the advantages of biodegradability, low toxicity, selectivity and biocompatibility over chemically synthesized surfactants. The goal of the study is to present a novel bioemulsifier with great application potential. Methods and Results: Aeribacillus pallidus YM‐1, isolated from crude oil contaminated soil, was found to produce a novel high molecular bioemulsifier with an emulsification index of 60 ± 1% without remarkable surface tension reduction (45·7 ± 0·1 mN m^?1). The number‐average molecular weight was determined as 526 369 Da by gel permeation chromatography analysis. Bioemulsifier was subjected to FT‐IR and a complex of carbohydrates (41·1%), lipids (47·6%) and proteins (11·3%) was determined. Conclusions: The bioemulsifier of A. pallidus YM‐1 was isolated from the glucose‐based culture medium and characterized with the help of chemical analytical techniques. The bioemulsifier exhibited a promising emulsifying property for biotechnology application potential in bioremediation and microbial enhanced oil recovery. Significance and Impact of the Study: This is the first report of the bioemulsifier production by A. pallidus. The potential emulsifying activity of the bioemulsifier in the present study may be explored in various biotechnological and industrial applications.     

Production of a peptidoglycolipid bioemulsifier by Pseudomonas aeruginosa grown on hydrocarbon

A strain of Pseudomonas aeruginosa isolated from a polluted soil was found to produce an extracellular bioemulsifier when cultivated on hexadecane as sole carbon source. The emulsifier was precipitated with acetone and redissolved in sterile water. Dodecane, crude oil and kerosene were found to be good substrates for emulsification by the bioemulsifier. Growth and bioemulsifier production reached the optimal levels on the fourth and fifth day, respectively. Emulsifying activity was observed over a pH range of 3.5 to 10.0 with a maximum at pH 7.0. The activity of the bioemulsifier was heat stable up to 70 degrees C while about 50 percent of its activity was retained at 100 degrees C. The components of the bioemulsifier were determined, it was found to contain carbohydrate, protein and lipid. The protein complex was precipitated with ammonium sulphate and fractionated on a Sephadex G-100. Gel electrophoresis of the bioemulsifier showed a single band whose molecular weight was estimated as 14,322 Da. The bioemulsifier was classified as a peptidoglycolipid. Certain strains of P. aeruginosa produce peptidoglycolipid in place of rhamnolipid.     

Characteristics of bioemulsifier V2-7 synthesized in culture media added of hydrocarbons: chemical composition, emulsifying activity and rheological properties

The bioemulsifier V2-7 is an exopolysaccharide (EPS) synthesized by strain F2-7 of Halomonas eurihalina and it has the property of emulsifying a wide range of hydrocarbons i.e. n-tetradecane, n-hexadecane, n-octane, xylene mineral light and heavy oils, petrol and crude oil. Characteristics of exopolysaccharide V2-7 produced in media supplemented with various hydrocarbons (n-tetradecane, n-hexadecane, n-octane, xylene, mineral light oil, mineral heavy oil, petrol or crude oil) were studied. Yield production varied from 0.54 to 1.45 g L(-1) according to the hydrocarbon added, in the same way chemical composition, viscosity and emulsifying activity of EPS varied with the culture conditions. Respect to chemical composition, percentage of uronic acids found in exopolymers produced in hydrocarbon media was always higher than that described for V2-7 EPS (1.32%) obtained with glucose. This large amount of uronic acid present could be useful in biodetoxification and waste water treatment. On the other hand, the highest amount of biopolymer was synthesized with mineral light oil, while the most active emulsifiers were those obtained from media added with petrol and n-octane. Furthermore, all EPS were capable of emulsifying crude oil more efficiently than the three chemical surfactants tested as control (Tween 20, Tween 80 and Triton X-100). The capacity of strain F2-7 to grow and produce bioemulsifier in presence of oil hydrocarbons together with the high emulsifying activity and low viscosity power of the biopolymers synthesized in hydrocarbons media could be considered highly beneficial for application of both bioemulsifier and producing strain in bioremediation of oil pollutants.     

Evaluation of bioemulsifier mediated Microbial Enhanced Oil Recovery using sand pack column

Bacillus licheniformis K125, isolated from an oil reservoir, produces an effective bioemulsifier. The crude bioemulsifier showed 66% emulsification activity (E(24)) and reduced the surface tension of water from 72 to 34 mN/m. It contains substantial amount of polysaccharide, protein and lipid. This bioemulsifier is pseudoplastic non-Newtonian in nature. It forms oil in water emulsion which remains stable at wide range of pH, temperature and salinity. It gave 43+/-3.3% additional oil recovery upon application to a sand pack column designed to simulate an oil reservoir. This is 13.7% higher than that obtained from crude lipopeptide biosurfactants produced by the standard strain, Bacillus mojavensis JF2 and 8.5% higher than hot water spring isolate, Bacillus licheniformis TT42. The increased oil recovery obtained by using the crude bioemulsifier can be attributed to its combined surface and emulsification activity. Its mechanism of oil recovery must be similar to the mechanism exhibited by surfactant-polymer flooding process of chemical enhanced oil recovery.     

仙人掌超微粉挥发性成分研究

目的：研究仙人掌中的挥发性成分。方法：利用水蒸气蒸馏法提取经超微粉碎后的仙人掌[Opuntia dillenii（Ker-Gaw.）Haw]挥发油,用GC-MS进行测定,结合计算机检索技术对分离的化合物进行结构鉴定,应用色谱峰面积归一化法计算各成分的相对百分含量。结果：共分离鉴定出32个化学成分,占总成分的98.097%,其中相对百分含量大于2%的分别确定为异丁基邻苯二甲酸酯（Isobutyl phthalate）27.492%,棕榈酸（Palmitic acid）16.716%,丁基邻苯二甲酸酯（Butyl phthalate）11.257%,薄荷脑（Menthol）6.722%,亚油酸（Linoleic acid）5.995%,壬醛（Nonanal）4.594%,乙醛（Hexanal）3.614%,十二酸（Dodecanic acid）3.244%。结论：通过对仙人掌超微粉挥发性成分的分析鉴定及相对含量测定,为综合利用仙人掌植物资源等提供科学依据。     

Studies on bioemulsifier production by Acinetobacter strains isolated from healthy human skin

AIMS: In recent years, interest has been growing in the search for novel bioemulsifiers. Many bacterial genera including Acinetobacter have been reported to produce bioemulsifiers. The present study aims to screen Acinetobacter isolates from healthy human skin for bioemulsifier production. Methods and Results: Acinetobacter junii SC14 produced maximum bioemulsifier in the presence of almond oil during stationary growth phase at 37 degrees C and pH 7.2. Partially purified, nondialysable bioemulsifier from SC14 was a proteoglycan. The protein and polysaccharide fractions resulted in 95.2% reconstitution of the emulsification activity. The role of esterase in the release of cell-bound emulsifier and the contribution of capsular polysaccharide to the emulsification activity were observed. CONCLUSION: Acinetobacter strains from human skin exhibited better emulsification activity than that by burn wound or soil isolates, owing to the inherent differences in chemical microenvironment of their habitats. SIGNIFICANCE AND IMPACT OF THE STUDY: Investigation of skin commensals, especially acinetobacters, would lead to the discovery of novel bioemulsifiers with interesting properties. Attempts of screening and strain improvement directed towards skin commensals will open up new avenues for strains producing bioemulsifier on a commercial scale.     

Bioemulsifier production by Streptomyces sp. S22 isolated from garden soil

Out of 45 actinomycetes isolated from garden soil, pond water and air; fifteen showed good emulsification activity. Streptomyces sp. S22 isolated from garden soil produced maximum bioemulsifier with 0.5% (v/v) sunflower oil during stationary phase at 37 degrees C, pH 6 and 250 rev/min. Emulsification activity was maximum (320 EU/ml) with sunflower oil as substrate. Partially purified bioemulsifier from Streptomyces sp. S22 was a peptidoglycolipid containing lipid (51.25%), protein (30%), non-reducing sugar (17.75%) and reducing sugar (1%). The yield of partially purified bioemulsifier was 1.6 g/l and reduced the surface tension of water by 23.09 mN/m. The bioemulsifier produced by Streptomyces sp. S22 was stable at room temperature for seven days.     

Major and minor QTL and epistasis contribute to fatty acid compositions and oil concentration in high-oil maize

High-oil maize is a useful genetic resource for genomic investigation in plants. To determine the genetic basis of oil concentration and composition in maize grain, a recombinant inbred population derived from a cross between normal line B73 and high-oil line By804 was phenotyped using gas chromatography, and genotyped with 228 molecular markers. A total of 42 individual QTL, associated with fatty acid compositions and oil concentration, were detected in 21 genomic regions. Five major QTL were identified for measured traits, one each of which explained 42.0% of phenotypic variance for palmitic acid, 15.0% for stearic acid, 27.7% for oleic acid, 48.3% for linoleic acid, and 15.7% for oil concentration in the RIL population. Thirty-six loci were involved in 24 molecular marker pairs of epistatic interactions across all traits, which explained phenotypic variances ranging from 0.4 to 6.1%. Seven of 18 mapping candidate genes related to lipid metabolism were localized within or were close to identified individual QTL, explaining 0.7–13.2% of the population variance. These results demonstrated that a few major QTL with large additive effects could play an important role in attending fatty acid compositions and increasing oil concentration in used germplasm. A larger number of minor QTL and a certain number of epistatic QTL, both with additive effects, also contributed to fatty acid compositions and oil concentration.     

木鳖子种仁油中特殊脂肪酸成分的研究

<正> 葫芦科植物木鳖子Momordica cochinchinensis (Lour.) Spr.的种子入药,功能消肿、散结、祛毒。它分布于我国四川、湖北、河南、安徽,浙江、福建、广东、广西、贵州和云南等地。该种子富含油脂,种仁含油率高达41.2％。其化学组成,经气相色谱法鉴定其混合脂肪酸甲酯,紫外光谱和红外光谱测试其混合脂肪酸,同时制备其顺丁烯二酸酐的衍生物,通过熔点,红外光谱及质谱法鉴定此衍生物,证实该种子油中含有29.02％的α-桐酸组分。