假单胞菌O-2-2利用油脂废水生产鼠李糖脂研究

通过摇瓶培养试验,研究了铜绿假单胞菌O-2-2以植物油精炼废水为原料生产鼠李糖脂生物表面活性剂的适宜条件.结果表明以NaNO3为氮源,碳氮比为15,培养基初始pH值为7.5,32℃,250 r/min培养84 h,鼠李糖脂产量最高,达2.14g/L.液-质联用分析结果表明所提取的糖脂由11种同系物组成,都含有1～2个的鼠李糖和1～2个含β-羟基的碳链长度为8～12的饱和或不饱和脂肪酸.该糖脂生物表面活性剂的临界胶束浓度为69.5 mg/L,可将水的表面张力降至29.2 mN/m,并具有良好的耐温耐盐性.     

假单胞菌AB93066产鼠李糖脂发酵条件的优化

通过单因素实验和正交实验对铜绿假单胞杆菌AB93066产鼠李糖脂(RL)的摇瓶发酵培养基配方和产生规律进行了研究。结果表明,最佳培养基配方为:ρ(酵母膏)=0.2 g/L,ρ(豆油)=120 g/L,ρ(NaNO3)=6.5 g/L,ρ(KH2PO4)=1.0 g/L,ρ(Na2HPO4.12H2O)=1.0 g/L,ρ(MgSO4.7H2O)=0.1 g/L,ρ(FeSO4.7H2O)=0.2 g/L,pH=6.0。RL的收获期在发酵后156~168 h最佳。发酵生产RL的扩大实验表明,在最优发酵条件下RL的产量可达56 g/L以上,提取后的RL可将去离子水的表面张力降至29.01 mN/m。用高效液相色谱/质谱联用仪进一步分析了所提取的RL的组成,它分别为二鼠李糖脂(R1)和单鼠李糖脂(R2)两种同系物。R1和R2的表观临界胶束浓度(CMC)分别为0.03 mmol/L和0.04 mmol/L。     

鼠李糖脂产量的提高及采油应用研究

对一株铜绿假单胞菌进行发酵条件优化,最优培养基为：菜籽油80 g/L、NaNO₃ 6 g/L、Na₂HPO₄·12H₂O 3 g/L、KH₂PO₄ 1.5 g/L、MgSO₄ 0.36 g/L、FeSO₄·7H₂O 0.2 g/L、CaCl₂ 0.12 g/L;最适培养条件为：温度37℃,装液量40 mL/250 mL,发酵时间168 h。在最优条件下,鼠李糖脂平均产量可达57.83 g/L,表面张力降到27.89 mN/m。鼠李糖脂在相对苛刻的温度、盐度、pH环境中具有较强的稳定性。在物理模拟驱油实验中,用发酵液进行实验,添加具有增黏性质的生物聚合物黄原胶辅助,建立了一种新的生物驱油体系。5%鼠李糖脂发酵液的生物复合体系采收率可达17.4%,表明其在微生物采油领域有着较大的应用前景。     

微生物合成鼠李糖脂生物表面活性剂的研究进展

微生物合成的鼠李糖脂是一类重要的生物表面活性剂,具有易被生物降解、表面活性良好等优点,应用前景广阔。目前用于发酵合成鼠李糖脂的菌株主要为假单胞菌属。综述了产鼠李糖脂菌株的发现与筛选、鼠李糖脂的生物合成途径与代谢调控关系、鼠李糖脂发酵过程的优化与控制、高产鼠李糖脂工程菌株的构建等方面的研究进展,并对其研究趋势进行了展望。     

鼠李糖脂的发酵及其在清洗原油储罐中的应用

从被油类污染的土壤中得到一株分泌鼠李糖脂的铜绿假单胞菌P aeruginosa ZJU u1,利用烹饪废油为碳源,在摇瓶上对此菌株进行发酵培养,鼠李糖脂的产量在120 h后达到12.54 g/L.获得的发酵液可以使溶液表面张力降低到37×10-3 N/m,临界胶束浓度(CMC)为63.3 mg/L.实验结果表明,发酵液可提高罐底油泥的洗脱效果,提高储油罐罐底油泥中原油的回收率.     

鼠李糖脂的发酵及其在清洗原油储罐中的应用

从被油类污染的土壤中得到一株分泌鼠李糖脂的铜绿假单胞菌P aeruginosa ZJU u1,利用烹饪废油为碳源,在摇瓶上对此菌株进行发酵培养,鼠李糖脂的产量在120 h后达到12.54g/L.获得的发酵液可以使溶液表面张力降低到37×10-3N/m,临界胶束浓度(CMC)为63.3 mg/L.实验结果表明,发酵液可提高罐底油泥的洗脱效果,提高储油罐罐底油泥中原油的回收率.     

鼠李糖脂强化白腐菌处理制浆黑液效果研究

研究了吐温、鼠李糖脂、硫酸铜和乙醇等不同添加物对白腐菌处理黑液效果的强化作用,发现鼠李糖脂能够较好地强化修复效果,当其质量浓度在50~60 mg/L时处理效果最佳。将产生鼠李糖脂的铜绿假单胞菌与白腐菌共同接种黑液后培养,可将COD降低44%。本研究为黑液的微生物处理提供了新的思路。     

鼠李糖脂钙的制备及物理化学性质表征

鼠李糖脂是一种生物表面活性剂,由于其表面活性好及环境友好特性,在环境、石油和日化等领域都有广泛应用,但在日化方面的应用受限于其颜色深、不易保存与运输。研究以鼠李糖脂为原料制备色泽浅且呈固态的鼠李糖脂钙,并研究其结构、表面活性及物理化学性质。核磁和红外结果显示,鼠李糖脂钙具有与鼠李糖脂相同的主体结构。分析表明鼠李糖脂钙由质量分数为3.12%的钙离子和质量分数为36.22%的鼠李糖构成,钙原子与鼠李糖脂的物质的量比为1:2。热重分析测得鼠李糖脂钙熔点约为125℃,显著高于鼠李糖脂的熔点(83℃),但二者热分解稳定性却相差不大。此外,鼠李糖脂钙可将水的表面张力降至27 mN·m^-1左右,其临界胶束浓度(CMC)为223.7 mg·L^-1,具有与鼠李糖脂相似的表面活性。综上,鼠李糖脂钙表面活性好、色度低且以固体形式存在,是比较理想的用于日化行业的生物表面活性物质。     

利用废弃碳资源生产鼠李糖脂的研究进展

鼠李糖脂是微生物合成的一类糖脂类生物表面活性剂,具有优异的表面活性、理化性质和广阔的应用前景。铜绿假单胞菌是鼠李糖脂生产的主要发酵菌株,能够以多种水溶性碳源或疏水性碳源为底物发酵生产鼠李糖脂。当前,废弃碳资源导致的浪费和污染问题日益严峻,基于鼠李糖脂的特性与生产菌株的底物偏好性,以废弃碳资源为原料生产鼠李糖脂具有很大的发展潜力。本文分别介绍以废油脂(含油废水、食品加工废油和餐厨废油)、含糖废弃物(含糖的食品加工副产物、含糖果蔬废弃物和木质纤维)和废塑料等高聚废弃物为原料合成鼠李糖脂的研究进展,重点总结了不同底物和生产菌株对鼠李糖脂生产的影响。通过分析废弃碳资源当前利用现状,发现繁多的种类、较低的分类程度和难降解的组分是限制以废弃碳资源作为底物生产鼠李糖脂进一步发展的主要因素,并提出以废弃碳资源生产鼠李糖脂的未来发展方向。     

鼠李糖脂在石油工业中的应用研究进展

鼠李糖脂是一种具有良好乳化作用、增溶作用以及可降低界面张力的生物表面活性剂。介绍了鼠李糖脂的结构及生产方法,综述了鼠李糖脂在石油工业中应用的研究进展,探讨了目前的研究热点及存在的问题,展望了鼠李糖脂今后的发展方向。     

利用油田废水电渗析脱盐液发酵制备鼠李糖脂的研究

采用回转式流道隔板型式的电渗析装置对高盐度油田废水进行处理。研究了电渗析两室浓差、浓淡比、油脂在膜表面吸附和清除方式等因素对含油废水脱盐效果的影响,给出了提高脱盐过程电流效率的方法,并比较了与常规处理过程的成本差异。然后采用含油脱盐水作为发酵用水,在500毫升摇瓶规模上进行铜绿假单孢杆菌的鼠李糖脂发酵实验,发酵5天后溶液中鼠李糖脂浓度可达0.2g.L-1,且发酵前后微生物对废水中油类物质的降解量达一半以上。     

Recovery of Rhamnolipids Produced by Pseudomonas aeruginosa Using Acidic Precipitation,Extraction, and Adsorption on Activated Carbon

Biosurfactants are produced by microorganisms, especially those of the genus Pseudomonas. This study is concerned with the recovery of rhamnolipids produced by Pseudomonas aeruginosa P029-GVIIA, using molasses as substrate. A central compound design 2³ in triplicate at the central point was used to evaluate, the influence of the centrifugation time, the agitation speed, and the pH on the amount of rhamnolipids precipitated by HCl (2 N). A 2⁴ factorial design in triplicate at the central point was used to investigate the influence of the pH (3–10), temperature (30 to 50°C), the concentration of carbon (1–3% w/v), and the agitation speed (100–200 rpm) on the adsorption of rhamnolipids to activated carbon. The tests showed that the adsorption is governed particularly by the pH and the temperature, as well as by the temperature × pH interaction. A pseudo-first order kinetic model successfully fitted the data, showing that the adsorbent had the ability to adsorb approximately 17.16 mg of rhamnolipids/gram of activated carbon.     

菌株Pseudomonas aeruginosa BC1发酵-渗透汽化耦合制备鼠李糖脂的研究

采用发酵-渗透汽化耦合(fermentation coupling with pervaporation,FCP)系统和分批补料式发酵系统培养Pseudomonas aeruginosa BC1制备生物表面活性剂鼠李糖脂,两轮发酵过程分别持续124 h和107 h。在FCP系统中,最大细胞吸光度OD600为1.06;生物表面活性剂OD600为0.61;鼠李糖脂最终产量为1.3 g/L,相比于分批补料式发酵系统提高38%;对比纯水的表面张力67.52 m N/m,发酵第29 h的发酵上清液表面张力为22.56 m N/m。同时,该菌的发酵上清液对液体石蜡、机油、柴油、正己烷、十六烷均有较好的乳化能力。经GC-MS结合SPME分析发现,FCP系统分离出的渗透蒸汽冷凝液中含有乙醇、戊醇等有机物。实验结果表明,相比分批补料式发酵系统,FCP系统能够分离发酵过程中产生的一部分挥发性代谢产物,减轻这些物质对细胞生长的抑制,使细胞浓度和鼠李糖脂产量都有明显提高。     

铜绿假单胞菌次生代谢产物的研究进展

铜绿假单胞菌可产生多种具有活性的次生代谢产物。综述了铜绿假单胞菌次生代谢产物的种类、提取方法、合成方法、作用机制及用途,指出了研究中存在的问题,展望了未来的发展方向,拟为铜绿假单胞菌次生代谢产物的科学研究提供参考。     

生物表面活性剂鼠李糖脂发酵条件的优化及绿色提取新工艺研究

通过正交实验对铜绿假单胞杆菌产鼠李糖脂（RL）的发酵条件进行了优化,并采用预处理酸沉淀冷冻干燥法新工艺提取RL。在最优发酵条件下RL的产量可达56 g/L以上。提取后的RL由二鼠李糖脂和单鼠李糖脂两种同系物组成,可将去离子水的表面张力降至29.01 mN/m。该RL提取工艺是一项绿色工艺。     

Characterization of Biosurfactant Produced by a Novel Strain of Pseudomonas aeruginosa,Isolate ADMT1

Several biosurfactant‐producing bacterial strains were isolated from petroleum‐contaminated soil. The isolate ADMT1, identified as a new strain of Pseudomonas aeruginosa, was selected for further studies on the basis of oil displacement test and emulsification index (E24). The optimal parameters for production, determined by employing Box–Behnken design, were temperature 36.5 °C and pH 7. The environmental isolate ADMT1 produced significant amount of biosurfactant (1.7 g L^?1 in 72 h) in minimal salt medium (MSM) using dextrose as the sole carbon source. The E24 value and critical micelle concentration (CMC) of the biosurfactant was 100% and 150 mg L^?1, respectively. At CMC, the surface tension of water was reduced to 28.4 mN m^?1. The biosurfactant exhibited hemolytic activity and antibacterial activity against 8 reference strains of pathogenic bacteria, including 2 methicillin‐resistant Staphylococcus aureus strains (MRSA ATCC 562 and MRSA ATCC 43300), with minimum inhibitory concentration (MIC) of 0.4 and 0.2 mg mL^?1, respectively. The structure of biosurfactant was characterized by FTIR, ¹H, and ¹³C NMR spectroscopy. 7 di‐rhamnolipid (RL) congeners were identified in the biosurfactant by ultraperformance liquid chromatography–mass spectrometry analysis. The major congeners, which constituted 67% of the RL mixture, included Rha‐Rha‐C₁₀‐C₁₀, Rha‐Rha‐C₁₂‐C₁₀, and Rha‐Rha‐C_12:1‐C₁₀. The minor congeners were Rha‐Rha‐C₁₀‐C₈, Rha‐Rha‐C_10:1‐C₁₀, Rha‐Rha‐C₁₀‐C_14:1, and Rha‐Rha‐C₁₀‐C₁₄. The congener Rha‐Rha‐C₁₀‐C₁₄ is being reported for the first time from any species of Pseudomonas. The high surface activity and E24 value make the ADMT1‐RL a potential candidate for its use in detergents, environmental bioremediation, and as an emulsifier in the food industry.     

Cells Were a More Important Foaming Factor than Free Rhamnolipids in Fermentation of Pseudomonas aeruginosa E03-40 for High Rhamnolipid Production

Rhamnolipids are among the best‐known biosurfactants. Severe foaming occurs in aerobic rhamnolipid fermentation and negatively affects operation and economics of the biosurfactant production. In this study the foaming properties were examined with samples taken along a Pseudomonas aeruginosa fermentation that produced 55 g l^?1 rhamnolipids with a maximum volumetric productivity of 0.080 g l^?1 h^?1 and a maximum specific productivity of 0.013 g g^?1 h^?1. For a better understanding of the process, the broth samples were also centrifuged to prepare cell‐free supernatants and cell suspensions in water, and all samples were evaluated under fixed foaming conditions. In addition to the time profiles of foam rise, the initial foaming rates and maximum foam volumes were determined. Contrary to the general assumption, the cells, not rhamnolipids, were the main foaming agents in the fermentation. Soluble components including rhamnolipids had secondary roles. Supernatant foaming was higher after the culture entered the rhamnolipid‐producing stationary phase; however, the foaming appeared to decrease with increasing rhamnolipid concentrations at high concentrations (>15 g l^?1). The pH effects on foaming of broths, supernatants, and cell suspensions were also studied. Broth foaming was 55 and 80 % less at pH 5.5 and 5.0, respectively, compared to that at pH 6.5. Cell growth and rhamnolipid production at lower pH should be included in future studies. In addition, strain selection or genetic engineering and medium modification to reduce cell hydrophobicity are suggested as useful strategies to address the foaming issue of rhamnolipid fermentation.     

Characterization and emulsification properties of rhamnolipid and sophorolipid biosurfactants and their applications

Due to their non-toxic nature, biodegradability and production from renewable resources, research has shown an increasing interest in the use of biosurfactants in a wide variety of applications. This paper reviews the characterization of rhamnolipid and sophorolipid biosurfactants based on their hydrophilicity/hydrophobicity and their ability to form microemulsions with a range of oils without additives. The use of the biosurfactants in applications such as detergency and vegetable oil extraction for biodiesel application is also discussed. Rhamnolipid was found to be a hydrophilic surfactant while sophorolipid was found to be very hydrophobic. Therefore, rhamnolipid and sophorolipid biosurfactants in mixtures showed robust performance in these applications.     

Comparative Analysis of Rhamnolipids from Novel Environmental Isolates of Pseudomonas aeruginosa

A comparative analysis of rhamnolipids from environmental isolates of Pseudomonas aeruginosa was undertaken to evaluate strain-specific rhamnolipid fingerprints obtained under different growth conditions. Environmental isolates of P. aeruginosa produced rhamnolipids on different types of substrates, including cheap and renewable sources like sunflower oil from deep fryers and sunflower oil mill effluent. Rhamnolipids were monitored by high-performance liquid chromatography–electrospray ionization interface mass spectrometry, which allowed fast and reliable identification and quantification of the congeners present. The highest concentration of total rhamnolipids of 3.33 g/l was obtained by the strain P. aeruginosa 67, recovered from petroleum contaminated soil, and strains D1 (1.73 g/l) and D2 (1.70 g/l), recovered from natural microbial consortia originated from mazut-contaminated soil, grown on sunflower oil as a carbon source. Di- to mono-rhamnolipids ratios were in the range of 0.90–5.39 for different media composition and from 1.12 to 4.17 for different producing strains. Rhamnolipid profiles of purified mixtures of all tested strains are similar with chain length from C₈–C₁₂, pronounced abundance of Rha–C₁₀–C₁₀ and Rha–Rha–C₁₀–C₁₀ congeners, and a low content of 3-(3-hydroxyalkanoyloxy)-alkanoic acids. Concentrations of major congeners of RLs were found to slightly vary, depending on strain and growth conditions, while variations in minor congeners were more pronounced. Statistically significant increase of critical micelle concentration values was observed with lowering the ratio of total mono- to di-rhamnolipids ratio indicating that mono-rhamnolipids start to form micelles at lower concentration than di-rhamnolipids.