槐糖脂的生物合成、发酵及分离纯化

槐糖脂是一类由酵母菌代谢生产的糖脂型生物表面活性剂,具有优越的表/界面活性和稳定性,且无毒、无刺激、易被生物降解,在众多领域具有良好的应用前景,被认为是最具潜力替代化学表面活性剂的生物表面活性剂之一。历经50余年的研究,槐糖脂的发酵生产工艺日趋成熟,但产品的分离纯化仍是难点。本文系统地综述了槐糖脂的结构、生物合成途径,重点关注近年来槐糖脂的发酵生产研究现状,以及分离纯化研究现状。并对槐糖脂的发酵生产和分离研究进行了展望,旨在促进槐糖脂的规模化生产与市场化发展。     

一株高产表面活性剂的南极土地杆菌的分离及其特性

【背景】生物表面活性剂具有毒性低、生物兼容性好和可降解等优点,是化学表面活性剂的优良替代物。目前产生物表面活性剂的微生物多为常温菌,从低温环境中挖掘高产新型生物表面活性剂的生产菌株具有重要的意义。【目的】从南极土壤中筛选产表面活性剂的低温微生物,对其表面活性剂进行纯化和结构解析并评估其性能。【方法】采用排油圈法对分离自南极菲尔德斯半岛土壤样品中的细菌菌株进行筛选,获得一株在菌苔表面产白色固体颗粒的菌株,对菌株进行形态观察和16SrRNA基因序列分析以确定该菌株系统发育地位。利用高效液相色谱法(high performance liquid chromatography, HPLC)分离产物,并用核磁共振波谱(nuclear magnetic resonance,NMR)技术对产物的化学结构进行鉴定。采用单因素试验和响应面设计方法对发酵培养基进行优化。此外,对产物的乳化性能及其对柴油的降解能力进行评估。【结果】得到了一株高产生物表面活性剂的耐冷土地杆菌属(Pedobacter)GW9-17,其最优发酵培养基(g/L)组成为：可溶性淀粉18.0、胰蛋白胨9.0、C3H3NaO3 4.4、K...     

表面活性剂对中性粒细胞的影响

本文探讨了一种新的筛选血细胞作用试剂的方法。中性粒细胞经分离纯化后,表面活性剂对其作用效果可避免受到其他血细胞的影响,能准确反应表面活性剂的作用效果。此方法是筛选血细胞作用试剂的理想方法。     

生物表面活性剂及其应用

生物表面活性剂主要是由微生物产生的一种生物在分子物质,具有或优于化学合成表面活性剂的理化特性,作为一种绿色天然产物。极有可能取代化学合成表面活性剂,其应用前景十分广阔。本文阔述了生物表面活性剂的特点,种类,着重介绍它的潜在应用。     

新型生物表面活性剂甘露糖赤藓糖醇脂（MEL）的分离与表面性质研究

本文通过对Ｃａｎｄｉｄａａｎｔａｒｃｔｉｃａ生产的生物表面活性剂甘露糖赤藓糖醇（ＭＥＬ）的分离条件的研究,得到了该生物表面活性剂分离的最佳条件：硅胶粒径２００目,洗脱剂分为氯信丙酮混合溶剂,配比分别是７：３（ＭＥＬ－Ａ）与６：４（ＭＥＬ－Ｂ）,洗脱速率为０．２５ｍｌ／ｍｉｎ,洗脱剂用量为４００ｍｌ／ｇＭＥＬ。对ＭＥＬ表面性质的研究发现其具有较好的表面活性,是一种良好的天然表面活性剂。     

生物表面活性剂的合成与提取研究进展*

生物表面活性剂（Biosurfactant）是由微生物产生的具有高表面活性的生物分子。相对于化学合成的表面活性剂,生物表面活性剂对生态系统的毒性较低,且可生物降解。因此,生物表面活性剂开始应用于环境污染治理的各个方面。中从生物表面活性剂生产菌的筛选、培养基的优化及生物表面活性剂的提取等方面对近年来生物表面活性剂的研究进展进行了总结,并对未来的发展方向作了展望。     

发酵法生产生物表面活性剂

发酵法生产表面活性剂相对于化工法而言有着无可比拟的优势。综述了发酵法生产生物表面活性剂的微生物源、发酵机理、发酵条件和产物分离技术等方面的研究进展 ,并简要介绍了其工业应用前景。     

石蜡酪杆菌B126产生糖脂的适宜条件

<正> 生物表面活性剂的研制是从本世纪70年代发展起来的。由于可产生表面活性剂的微生物种类、生物表面活性剂的类型及可作为其底物的原料较多,一些产品的性能与化学合成的相当,可降解性较大、比较安全,而日益受到注意。乙酸钙不动杆菌(Acinetobacter calcoaceticus)RAG-1产生的生物乳化剂Emulsan的商品化和生物表面活性剂在各种工业、尤其是石油工业中的可用性,也促进了该领域的发展。 糖脂是一类重要的生物表面活性剂。我们分离筛选到一株糖脂产生菌,鉴定为一新种:石蜡酪杆菌(caseobacter paraffinicnm)B126。本文报道该菌产生糖脂的适宜条件。     

生物表面活性剂生产及应用研究进展

生物表面活性剂主要是由微生物代谢产生的,具有疏水基团和亲水基团的两亲性物质,它们能显著降低表面与界面张力。与化学表面活性剂相比,生物表面活性剂具有毒性低、生物兼容性好、可降解等优点,在众多领域具有良好的应用前景,但生物表面活性剂的高生产成本限制了商业化发展。本文旨在分析微生物表面活性剂的生产,重点是生产过程和代谢途径的优化,以探索产量与成本的关键因素,为生物表面活性剂商业化发展提供解决方案。     

生物表面活性剂

引言表面活性分子是细胞膜的基本组分,以这个意义讲,“生物表面活性剂”是普遍存在的。较为实用的是将此专门名词用来表示得自特定微生物的可用的和可分离到的表面活性剂,即使就这一点来说,也不是那么容易地区分出专门释放出的表面活性剂和由受损细胞所放出的膜碎片的表面活性剂。众所周知的化学合成表面活性剂,在民用和工业上具有广泛的用途,这导致发展出用途不同、性能各异的种类繁多的表面活性剂,但对这些表面活性的性能并非都了解得很透彻。这也产生了这样一种想法,即生物来源的表面活性剂会扩大现有表面活性剂的范围,在某些情     

Potential application of cyclic lipopeptide biosurfactants produced by Bacillus subtilis strains in laundry detergent formulations

AIMS: Crude cyclic lipopeptide (CLP) biosurfactants from two Bacillus subtilis strains (DM-03 and DM-04) were studied for their compatibility and stability with some locally available commercial laundry detergents. METHODS AND RESULTS: CLP biosurfactants from both B. subtilis strains were stable over the pH range of 7.0-12.0, and heating them at 80 degrees C for 60 min did not result in any loss of their surface-active property. Crude CLP biosurfactants showed good emulsion formation capability with vegetable oils, and demonstrated excellent compatibility and stability with all the tested laundry detergents. CONCLUSION: CLP biosurfactants from B. subtilis strains act additively with other components of the detergents to further improve the wash quality of detergents. The thermal resistance and extreme alkaline pH stability of B. subtilis CLP biosurfactants favour their inclusion in laundry detergent formulations. SIGNIFICANCE AND IMPACT OF THE STUDY: This study has great significance because it is already known that microbial biosurfactants are considered safer alternative to chemical or synthetic surfactants owing to lower toxicity, ease of biodegradability and low ecological impact. The present study provides further evidence that CLP biosurfactants from B. subtilis strains can be employed in laundry detergents.     

Biosurfactants,an help in the biodegradation of hexadecane? The case of <Emphasis Type="Italic">Rhodococcus</Emphasis> and <Emphasis Type="Italic">Pseudomonas</Emphasis> strains

The roles of the extracellular biosurfactants produced by two bacterial strains, Pseudomonas aeruginosa GL1 and Rhodococcus equi Ou2, in hexadecane uptake and biodegradation were compared. For this purpose, cell hydrophobicity and production of glycolipidic biosurfactants were evaluated during bacterial growth on hexadecane, as well the effects of these biosurfactants on culture supernatants properties i.e., surface and interfacial tensions, and emulsification and pseudosolubilization capacities. The results showed that the role of biosurfactants was different in these two strains and was directly related to the hydrophobicity of the bacterial cells concerned. Extracellular biosurfactants produced by strain R. equi Ou2 had only a minor role in hexadecane degradation. Direct interfacial accession appeared to be the main mechanism for hexadecane uptake by the hydrophobic cells of strain R. equi Ou2. On the contrary, the biosurfactants produced by P. aeruginosa GL1 were required for growth on hexadecane, and their pseudosolubilization capacity rather than their emulsification capacity was involved in substrate degradation, allowing uptake from hexadecane micelles by the hydrophilic cells of this bacterium. The roles of biosurfactants thus differ widely among bacteria degrading hydrophobic compounds. J.-P. Vandecasteele—in retirement     

Potential applications of microbial surfactants in biomedical sciences

The main commercial use of biosurfactants is in pollution remediation because of their ability to stabilize emulsions. This enhances the solubility and availability of hydrophobic pollutants, thus increasing their potential for biodegradation. One useful property of many biosurfactants that has not been reviewed extensively is their antimicrobial activity. Several biosurfactants have strong antibacterial, antifungal and antiviral activity. Other medically relevant uses of biosurfactants include their role as anti-adhesive agents to pathogens, making them useful for treating many diseases and as therapeutic and probiotic agents. Here, we discuss some of the new and exciting applications and related developments of various microbial surfactants in the field of biomedical sciences.     

生物表面活性剂修复重金属污染研究进展

重金属在环境中积累会对动植物和人体健康造成危害。生物表面活性剂环境相容性好,在环境污染修复方面的应用日益受到关注。本文介绍了生物表面活性剂及其在重金属污染修复中的应用;生物表面活性剂与重金属络合的机理;影响二者络合的因素(如pH值、表面活性剂浓度、重金属存在形态等);对生物表面活性剂修复重金属污染的前景进行了展望。     

Production and surface-active properties of microbial surfactants

A new source of surface-active compounds produced by microbes was investigated. These biologically derived surfactants (biosurfactants) were found to be extracellular products of two newly isolated Corynebacterium species, which were gorwn on kerosene (Imperial Oil No.9). Batch-growth kinetic studies were carried out in a 14 liter fermentor and the production of biosurfactants was found to be cell growth associated. The surface tension of the whole microbial broth was reduced to a minimum of about 30 dyn/cm, as compared with the surface tension for distilled water of 72 dyn/cm. The crude biosurfactants were recovered from the cell-free broth, freeze-dried, redissolved in water, and their surface-active properties were studied. The biosurfactants reported here were found to be nontoxic and their ability to lower the surface tension of water was found to be comparable to that of sodium dodecylbenzene sulfonate, common commercial synthetic surfactant.     

Multiple roles of biosurfactants in structural biofilm development by Pseudomonas aeruginosa

Recent studies have indicated that biosurfactants produced by Pseudomonas aeruginosa play a role both in maintaining channels between multicellular structures in biofilms and in dispersal of cells from biofilms. Through the use of flow cell technology and enhanced confocal laser scanning microscopy, we have obtained results which suggest that the biosurfactants produced by P. aeruginosa play additional roles in structural biofilm development. We present genetic evidence that during biofilm development by P. aeruginosa, biosurfactants promote microcolony formation in the initial phase and facilitate migration-dependent structural development in the later phase. P. aeruginosa rhlA mutants, deficient in synthesis of biosurfactants, were not capable of forming microcolonies in the initial phase of biofilm formation. Experiments involving two-color-coded mixed-strain biofilms showed that P. aeruginosa rhlA mutants were defective in migration-dependent development of mushroom-shaped multicellular structures in the later phase of biofilm formation. Experiments involving three-color-coded mixed-strain P. aeruginosa biofilms demonstrated that the wild-type and rhlA and pilA mutant strains formed distinct subpopulations on top of each other dependent on their ability to migrate and produce biosurfactants.     

Evaluation of microbial surfactants for recovery of hydrophobic pollutants from soil

Summary Several microbially produced biosurfactants were evaluated for their ability to remove hydrophobic compounds from soil. The biosurfactants produced byPseudomonas aeruginosa UG2 andAcinetobacter calcoaceticus RAG-1 displayed the best results, with recovery of [¹⁴C]hexachlorobiphenyl from soil slurries of 48.0 and 41.9%, respectively.P. aeruginosa UG2 produced higher levels of extracellular biosurfactants than four otherP. aeruginosa strains.P. aeruginosa UG2 culture filtrate containing biosurfactants enhanced the recovery of several other individual hydrocarbons and polychlorinated biphenyl compounds, as well as several hydrocarbons in a mixture, from soil. The results, suggest that biosurfactants produced byP. aeruginosa UG2 have the potential for remediation of hydrophobic pollutants in soil environments.     

Inhibition of initial adhesion of uropathogenic Enterococcus faecalis by biosurfactants from Lactobacillus isolates.

In this study, 15 Lactobacillus isolates were found to produce biosurfactants in the mid-exponential and stationary growth phases. The stationary-phase biosurfactants from lactobacillus casei subsp. rhamnosus 36 and ATCC 7469, Lactobacillus fermentum B54, and Lactobacillus acidophilus RC14 were investigated further to determine their capacity to inhibit the initial adhesion of uropathogenic Enterococcus faecalis 1131 to glass in a parallel-plate flow chamber. The initial deposition rate of E. faecalis to glass with an adsorbed biosurfactant layer from L. acidophilus RC14 or L. fermentum B54 was significantly decreased by approximately 70%, while the number of adhering enterococci after 4 h of adhesion was reduced by an average of 77%. The surface activity of the biosurfactants and their activity inhibiting the initial adhesion of E. faecalis 1131 were retained after dialysis (molecular weight cutoff, 6,000 to 8,000) and freeze-drying. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy revealed that the freeze-dried biosurfactants from L. acidophilus RC14 and L. fermentum B54 were richest in protein, while those from L. casei subsp. rhamnosus 36 and ATCC 7469 had relatively high polysaccharide and phosphate contents.     

Characterization of biosurfactants and their use in pollution removal – State of the Art. (Review)

Surface-active compound of biological origin (biosurfactants) have only been described in the past few decades. With the advantage of biodegradability and production on renewable resources, biosurfactants have been gaining prominence and their applications are becoming wider. So far, literature contains mixed reports on the successes of the applications of biosurfactants and their economical viability. They remain compounds which are not very well understood, yet, with several important applications. The target industries for biosurfactant use are the petroleum remediation industries and environmental conservation agencies. These industries, however, seem reluctant to use them for fear of dealing with microbes or microbial products. This includes cleaning up oil spills from the environment, remediation of metal-contaminated soils or waste streams, mobilizing heavy oil sludge and enhanced oil recovery. The importance of biosurfactants, their production, characteristics and limited successes and applications in oil pollution remediation and oil storage tank cleaning are discussed.     

Rapid quantification of a microbial surfactant by a simple turbidometric method

Quantification of the biosurfactants produced by a variety of microorganisms is a time taking and difficult task due to the lack of rapid, efficient and accurate methods. This work presents a simple turbidometric method for quantification of crude biosurfactants based on their property to become insoluble at low pH values. Biosurfactants obtained from a Bacillus sp. using different carbon substrates showed a good linear correlation (R(2)>0.99) between biosurfactant concentrations and turbidity in the range of 1 to 10 g L(-1) of crude biosurfactants. The substrate specific equations (SSE) and generalized equations (GE) developed in this work effectively predicted the amount of crude biosurfactant produced in different sets of fermentation experiments validating the method. A similar linear correlation was also observed with biosurfactants obtained from two other strains, Bacillus circulans and Pseudomonas sp. This simple method may prove to be effective in fast, accurate and inexpensive quantification of crude biosurfactants produced by diverse bacteria.