脂肽类生物表面活性剂研究进展

脂肽是由微生物代谢产生的一类具有很强表面活性的生物表面活性剂,在医药、环境保护、化妆品和微生物采油等方面有良好的应用潜力。该文对脂肽的生产、分离、鉴定及应用进展进行了综述。引用文献45篇。     

脂肽类生物表面活性剂的研究进展

脂肽类生物表面活性剂是一类由微生物产生的次级代谢产物,具有独特的化学结构,表现出优良的表面活性和生理特性。简介了脂肽类生物表面活性剂的产生菌及其种类,重点介绍了海洋微生物所产的脂肽类表面活性剂,并展望了其研究前景。     

一株脂肽类生物表面活性剂产生菌的性能及其影响因素研究

通过对实验筛选出一株产脂肽类生物表面活性剂的菌株BW-23,进行性能及其影响因素研究.结果表明:脂肽表面活性剂的CMC浓度为70 mg/L时,表面张力为31.0 mN/m;发酵液稀释10倍后,乳化指数仍为24.72％;在10～60℃间菌株BW-23所产的生物表面活性剂的耐热性较好;菌株BW-23在pH值为5.0～8.0时表面活性最好;当NaCl浓度小于15％时,菌株BW-23水溶液的表面张力变化幅度最小;当Ca2+浓度达到5000 mg/L时,菌株BW-23水溶液的表面张力为30.5 mN/m.     

脂肽类生物表面活性剂在微生物采油中的应用

随着科学技术的进步,越来越多的生物物质被运用到石油开采过程中,同时发挥着重要的积极作用。脂肽是生物代谢过程中产生的一种具有表面活性功能的活性剂,在提高原油采收率方面具有很好的发展潜力。本文主要是在分析脂肽类生物表面活性剂的结构与特性的基础上,探讨其在微生物采油中的具体应用。     

4种脂肽类生物表面活性剂的性能及其影响因素研究

实验室培养石油耐生菌并分离出4种阴离子脂肽类生物表面活性剂A8、A10-EA、A10-MeOH和B3.采用铂金板法和液滴形状分析法分别测定其平衡表面张力和动态界面张力,并研究生物表面活性剂的乳化性能及其对芘污染土壤的淋洗作用.结果表明:A8、A10-EA、A10-MeOH和B3的临界胶束浓度(cmc)分别为1.014,...     

产脂肽生物表面活性剂细菌的筛选及培养基优化

利用变色圈法和噬油斑法从土壤样品中分离筛选出一株产生物表面活性剂的细菌菌株LB345,通过薄层层析(TLC)确定其所产生物表面活性剂为脂肽,并通过单因素实验及L9(34)正交实验对菌株的培养基配方进行了优化,确定优化培养基的组成(g/L):葡萄糖30,NaNO32,KH2PO410,Na2HPO410,FeSO42.5×10-4,MgSO4.7H2O 0.03,NaC l 5,CaC l20.4,酵母粉0.3,初始pH值5,培养温度37℃,发酵时间7 d。在上述条件下,菌株LB345的脂肽产量可达到0.7 g/L。     

脂肽-糖脂混合型生物表面活性剂的性能及助剂

分离提取了枯草芽孢杆菌Bacillus subtilis THY-8发酵产物中的生物表面活性剂,采用飞行时间质谱鉴定为鼠李糖脂和表面活性素、芬芥素等的混合物。考察了该混合型生物表面活性剂的性能,研究了其对油砂原油的驱油效率,并探索了合适的助剂种类及配伍浓度。结果表明,THY-8所产的脂肽-糖脂混合型生物表面活性剂具有良好的表面活性、热稳定性和乳化性,pH值为5.5时表面张力为27.59 mN/m,临界胶束浓度为15 mg/L;在70 ℃放置5天,表面张力基本不变;可将液体石蜡乳化形成粒径10～30 μm的乳液。正辛醇助剂与该混合生物表面活性剂复配后界面张力降低到10?3 mN/m,驱油效率提高3.2倍。含0.9 g/L生物表面活性剂的发酵液驱油效果与正辛醇-生物表面活性剂复配体系相当。     

一株产脂肽类生物表面活性剂菌株的分离及代谢产物分析

采用多次富集培养、血平板筛选方法,从新疆克拉玛依油田油水样中分离得到产生物表面活性剂菌株L1。该菌株与已培养的土壤芽孢杆菌(Brevibacillus agri)的16S rDNA序列同源性达到99%;其代谢产物具有降低表面张力的作用,可以将发酵液表面张力从最初的69.56 mN.m-1降到29.36 mN.m-1;菌株代谢产物经薄层层析分析初步鉴定为脂肽类生物表面活性剂,红外光谱定性该生物表面活性剂属于环脂肽类表面活性剂。     

生物表面活性剂产生菌的诱变育种及特性研究

以铜绿假单胞菌(Pseudomonas aeruginosa)FC-69为出发菌株,以排油圈直径和生物表面活性剂产量为考核指标,采用紫外线和亚硝基胍复合诱变,筛选到一株生物表面活性剂高产菌株FC-69-52,并对其遗传稳定性和特性进行了研究.结果表明,高产菌株FC-69-52的排油圈直径达到7.12 cm、生物表面活性...     

生物表面活性剂

生物表面活性剂具有优于化学合成表面活性剂的理化特性,包括从动植物材料中提取、微生物发酵 和酶法3种合成方法;作为一种绿色天然产物,可应用于石油化工、生物修复、食品工业、化妆品和医药;目前,生物 表面活性剂的高成本影响了其广泛应用,若价格能达到消费者可以接受的水平,其应用前景将十分广阔。     

Foaming properties of surfactin,a lipopeptide biosurfactant fromBacillus subtilis

Foaming properties of surfactin were investigated and compared to those of sodium dodecyl sulfate (SDS) and bovine serum albumin (BSA). Foams were formed by a bubbling technique. Evolution of the foam volume and the liquid in the foam was monitored with optical and conductimetric methods to characterize foam formation and stability. Excellent foaming properties of surfactin were shown by its higher ability to form and stabilize the foam at a concentration as low as 0.05 mg/mL, in comparison with SDS and BSA. Surfactin produced a foam with intermediate maximum density and stabilized the liquid in foam, as well as BSA.     

Bioremediation of Polycyclic Aromatic Hydrocarbon Contaminated Soil by a Microbial Consortium through Supplementation of Biosurfactant Produced by Pseudomonas aeruginosa Strain

Lipopeptide biosurfactant produced by Pseudomonas aeruginosa Lbp 3 strain isolated from petroleum contaminated soil was investigated for its potential to enhance bioavailability, and hence, the biodegradation of polycyclic aromatic hydrocarbons (PAHs) in contaminated soil microcosms. Experiments were conducted on a soil spiked with equal parts of the PAHs Phenanthrene, Fluoranthene, and Pyrene to a final concentration of 1200 mg of total PAHs per kg of dry soil. To evaluate biodegradation enhancement efficiency, 50 g spiked soil samples were supplemented with 50 mgL^?1, 100 mgL^?1, 300 mgL^?1, and 1000 mgL^?1of lipopeptide dissolved in 30 mL of MSM, and incubated for 40 days at 30°C in darkness. Statistically significant (P < 0.05) biodegradation rates were observed in all the amended microcosms in comparison to the unamended controls. Maximal biodegradations (> 96% of Phenanthrene and Fluoranthene and > 93% of Pyrene) were observed in the soil microcosms supplemented with 1000 mgL^?1and 50 mgL^?1 lipopeptide. The effect of substrate interactivity of the PAHs on the biodegradation kinetics was also tested in comparison with sole substrate microcosms. Competitive inhibition of the biodegradation of low molecular weight PAHs was observed as a result of substrate interactivity in the multisubstrate system.     

Sustainable Production of Biosurfactant from Agro-Industrial Oil Wastes by Bacillus subtilis and Its Potential Application as Antioxidant and ACE Inhibitor

The microbial conversion of agro-industrial oil wastes into biosurfactants shows promise as a biomass refinery approach. In this study, Bacillus subtilis #309 was applied to produce surfactin using rapeseed and sunflower cakes, the most common oil processing side products in Europe. Studies of the chemical composition of the substrates were performed, to determine the feasibility of oil cakes for surfactin production. Initially, screening of proteolytic and lipolytic activity was performed to establish the capability of B. subtilis #309 for substrate utilization and hence effective surfactin production. B. subtilis #309 showed both proteolytic and lipolytic activity. The process of surfactin production was carefully analyzed by measurement of the surfactin concentration, pH, surface tension (ST) and emulsification index (E₂₄). The maximal surfactin concentration in the sunflower and rapeseed cake medium reached 1.19 ± 0.03 and 1.45 ± 0.09 g/L, respectively. At the same time, a progressive decrease in the surface tension and increase in emulsification activity were observed. The results confirmed the occurrence of various surfactin homologues, while the surfactin C₁₅ was the dominant one. Finally, the analysis of surfactin biological function exhibited antioxidant activity and significant angiotensin-converting enzyme (ACE)-inhibitory activity. The half-maximal inhibitory concentration (IC₅₀) value for ACE inhibition was found to be 0.62 mg/mL for surfactin. Molecular docking of the surfactin molecule to the ACE domains confirmed its inhibitory activity against ACE. Several interactions, such as hydrophobic terms, hydrogen bonds and van der Waals interactions, were involved in the complex stabilization. To the best of our knowledge, this is the first report describing the effect of a lipopeptide biosurfactant, surfactin, produced by B. subtilis for multifunctional properties in vitro, namely the ACE-inhibitory activity and the antioxidant properties, using different assays, such as 2,2-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP). Thus, the ACE-inhibitory lipopeptide biosurfactant shows promise to be used as a natural antihypertensive agent.     

Biosurfactants: Recent advances

Surfactants find applications in a wide variety of industrial processes. Biomolecules that are amphiphilic and partition preferentially at interfaces are classified as biosurfactants. In terms of surface activity, heat and pH stability, many biosurfactants are comparable to synthetic surfactants. Therefore, as the environmental compatibility is becoming an increasingly important factor in selecting industrial chemicals, the commercialization of biosurfactant is gaining much attention. In this paper, the general properties and functions of biosurfactants are introduced. Strategies for development of biosurfactant assay, enhanced biosurfactant production, large scale fermentation, and product recovery are discussed. Also discussed are recent advances in the genetic engineering of biosurfactant production. The potential applications of biosurfactants in industrial processes and bioremediation are presented. Finally, comments on the application of enzymes for the production of surfactants are also made.     

Biosurfactant-Assisted Bioremediation of Polycyclic Aromatic Hydrocarbons (PAHs) in Liquid Culture System and Substrate Interactions

A lipopeptide biosurfactant was produced by the bacterium Pseudomonas aeruginosa strain LBP9 isolated from petroleum-contaminated soil. Phenanthrene, fluoranthene, and pyrene were used as model polycyclic aromatic hydrocarbons (PAHs) to study the effect of the biosurfactant on the biodegradation of mixed and sole substrate PAHs, and examine substrate interactivity effects on their biodegradation in liquid culture. At 400 mg/L amendment of lipopeptide, the solubility of phenanthrene, fluoranthene, and pyrene were increased to 19, 33, and 45 times their aqueous solubility, respectively, and the extent of substrate utilization rate (q_max?) of PAHs was enhanced up to three-fold in the sole substrate studies in comparison to the unamended controls. In the ternary PAH mixture at total concentration of 300 mg/L, with equal parts of each PAH, 77%, 57%, and 33% degradation of phenanthrene, fluoranthene, and pyrene were observed, respectively, at 400 mg/L lipopeptide amendment on day 30 of incubation. Whereas in the sole substrate experiments at 300 mg/L concentration of each PAH and the same level of lipopeptide amendment more than 98% fluoranthene and 76% pyrene were degraded and phenanthrene removal was so rapid that at day 4 of incubation more than 80% was degraded. Biosurfactants at optimum amounts enhanced biodegradation of PAHs. Lipopeptide amendments of 200 mg/L and 400 mg/L were found out to be optimum amounts for statistically significant (p < 0.05) biodegradation of the PAHs in the experiments. However, despite biosurfactant-enhanced bioavailability of the PAHs, biodegradation rate was competitively inhibited in the multisubstrate microcosms.     

A novel alkylpolyglucoside-modified montmorillonite-filled starch bionanocomposites produced by extrusion

Native cassava starch was modified by dry heating treatment, and sodic montmorillonite was modified using an alkylpolyglucoside biosurfactant to produce a novel montmorillonite-filled starch bionanocomposites with improved performance. The bionanocomposites were produced in two extrusion steps using a co-rotating twin-screw extruder. The structural properties of the bionanocomposites were studied by X-ray diffraction. The reinforcement effect and material performance were evaluated by hydrophobicity, solubility, opacity, barrier, thermal and mechanical properties. In general, the dispersion of the nanofillers resulted in bionanocomposites with intercalated structures and improved properties compared with unfilled bioplastics. The main results exhibited that modified montmorillonite showed better compatibility with starch, improving nanofiller dispersion and interaction than the native one. As a result, it increased the hydrophobicity and reduced solubility, water, and oxygen permeabilities in comparison with bionanocomposites based on native starch by 36%, 48%, and 68%, respectively. Also, the tensile strength and Young modulus increased from 0.60 to 2.56 MPa and from 2.99 to 15.68 MPa, respectively. In conclusion, modification of MMT by the biosurfactant is a good approach to enhance dispersion/interaction with the starch matrix.     

Surfactin生物表面活性剂及其驱油研究进展

表面活性素（surfactin）是一类由革兰氏阳性的枯草芽孢杆菌产生的脂肽（lipopeptide）型生物表面活性剂,因其具有优于化学合成表面活性剂的若干优点,如低毒性、高生物降解性、更好的环境相容性,且在极端环境下稳定性好,在提高石油采收率方面有较好的应用潜力,但是目前只有少数的生物表面活性剂可以大规模生产实现工业化应用。本文介绍了surfactin生物表面活性剂的化学结构和生物合成机制,并对其发酵生产过程的影响因素进行分析,为提高其生产经济性探索不同的策略,例如使用更便宜的原材料、优化培养基组分、优化反应器等,系统论述了surfactin生物表面活性剂的驱油机理和其与化学合成表面活性剂的复配研究,同时针对其应用时的不足之处提出研究新思路。     

Time‐dependent dosing of Fe2+ for improved lipopeptide production by marine Bacillus megaterium

BACKGROUND: Lipopeptide production is strongly influenced by trace metals. The availability of free Fe²⁺ in the media throughout the process of fermentation was found to be very critical. Since free Fe²⁺ was reported to be sequestered by the lipopeptide as it was produced, intermittent feeding of Fe²⁺ was strategized and optimized for enhanced lipopeptide production by marine Bacillus megaterium in glucose mineral salts medium (GMSM). RESULTS: Studies with the single‐dose Fe²⁺ (0.48 mmol L^?1) supplementation after 8 h of fermentation resulted in lipopeptide concentration of 3.3 ± 0.1 g L^?1. Lipopeptide production was further enhanced to 4.2 ± 0.15 g L^?1 by adopting a multi‐dose Fe²⁺ feeding strategy. The maximum product yield (Y_P/S) of 0.24 ± 0.02 g g^?1 with specific product formation rate (q_p) of 0.124 ± 0.01 g g^?1 h^?1 was achieved when 0.48 mmol L^?1 Fe²⁺ was fed intermittently at different times as per the designed strategy. CONCLUSION: Lipopeptide concentration was improved 4.7‐fold by single‐dosing and 5.8‐fold by multiple dosing of Fe²⁺, when compared with GMSM without Fe²⁺ supplementation. Copyright © 2012 Society of Chemical Industry