环脂肽类生物表面活性剂结构、功能及生物合成

环脂肽是由微生物产生的一类生物表面活性剂,由亲水的肽环和亲油的脂肪烃链两部分组成,具有独特的化学结构和生理功能。除具表面活性外,环脂肽还具有抗真菌、抗细菌、抗病毒、抗肿瘤等生物活性,具有广阔的应用前景,但我国对这一领域的研究却刚刚起步。本文介绍了目前已知环脂肽的结构类型、结构与功能的关系、相关功能特点等,着重介绍了环脂肽生物合成的非核糖体多酶体系及合成酶基因操纵子,并对环脂肽的应用前景进行了展望。     

脂肽类生物表面活性剂的研究进展

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、食品、化妆品和微生物采油等方面有良好的应用潜力。本文对脂肽的生产、分离、鉴定及应用方面进行了综述     

一种脂肽类生物表面活性剂产生菌的筛选

从油田地层水中筛选分离得到1株能够产生表面活性剂的细菌,经鉴定为枯草芽孢杆菌。分析了该菌株的生理形态和生长特性,以及该菌株代谢产生的生物表面活性剂的性质。薄层色谱与原位水解显色和红外光谱分析表明,培养后菌株代谢产生的生物表面活性为脂肽。它能使水的表面张力降低到26mN/m,其临界胶束浓度为0.025mg/mL。     

环脂肽类生物表面活性剂结构、功能及生物合成*

环脂肽是由微生物产生的一类生物表面活性剂,由亲水的肽环和亲油的脂肪烃链两部分组成,具有独特的化学结构和生理功能。除具表面活性外,环脂肽还具有抗真菌、抗细菌、抗病毒、抗肿瘤等生物活性,具有广阔的应用前景,但我国对这一领域的研究却刚刚起步。本文介绍了目前已知环脂肽的结构类型、结构与功能的关系、相关功能特点等,着重介绍了环脂肽生物合成的非核糖体多酶体系及合成酶基因操纵子,并对环脂肽的应用前景进行了展望。     

石油降解菌X-1所产表面活性剂的研究

对石油污染土壤中筛选到的能产生生物表面活性剂的石油降解菌X-1(芽孢杆菌),进行表面活性剂的提取和鉴定,并对其产剂条件进行了优化。结果表明:菌株X-1产生的生物表面活性剂为浅黄色粉末状物质。通过硅胶板薄层层析和红外光谱分析,判定表面活性剂为脂肽、脂蛋白类物质。菌株X-1产生表面活性剂的最佳条件为:温度32℃,pH 7.0,盐度2 g/L NaCl,最佳碳源为淀粉,最佳氮源为蛋白胨。     

一株表面活性剂产生菌的筛选及其特性研究

从氧化沟含油污水中分离得到1株能产生物表面活性剂菌株S6(Pseudomonas sp.),经生理生化实验和16SrDNA序列分析鉴定,S6为铜绿假单胞菌。红外光谱分析得知S6在代谢过程中能够产生糖脂类表面活性物质。其临界胶束浓度(CMC)为50mg/L,可将水的表面张力由72mN/m降到33.9mN/m。发酵液的表面张力和排油直径的测定结果显示发酵液在不同的盐度、pH和溶解氧量条件下,具有较稳定的表面活性。通过正交实验确定了优化培养基条件为葡萄糖10g、尿素5g、磷酸二氢钾1g、微量元素液2mL、pH8.0、水1000mL;S6在优化培养基中合成生物表面活性剂的产量为0.173g/L。     

一株生物表面活性剂产生菌的分离及产剂性能研究

利用蓝色凝胶平板筛选法进行筛选,从华北某油田受污染的土壤中分离出一株优良的生物表面活性剂产生菌H1,生理生化反应及16S rDNA序列分析结果表明,该菌属于克雷伯氏菌属(Klebsiella),与Klebsiella pneumoniae同源性为99%。产剂性能研究试验表明,以4 g/L的蔗糖为碳源,以3 g/L的硝酸铵为氮源,初始pH值为7.0,30℃的培养条件有利于该生物表面活性剂的合成。     

一株高效表面活性剂产生菌的筛选及其活性产物的结构与性质

采用血平板法结合表面张力法从大庆油田高台子低渗透油藏采出水中筛选出一株高效表面活性剂产生菌,编号为DY-9.16S rDNA序列同源性比对结果显示,DY-9与地衣芽孢杆菌(Bacillus licheniformis)的序列相似性达99％.在45℃、180 r·min-1振荡培养条件下,DY-9在20 g·L-1糖蜜为碳源的培养基中生长良好,24h内将发酵液的表面张力从初始的69.3 mN·m-1降低至26.5 mN·m-1.48 h发酵液中表面活性剂粗品的产量达0.48 g·L-1,其临界胶束浓度为28 mg·L-1.菌株产生的表面活性剂在高温(120℃,1h)、高盐(12％ NaCl)及较宽的pH(2～12)条件下保持稳定,溶液的表面张力低于30 mN·m-1.经傅里叶变换红外光谱(IF-TR)和高效液相色谱-质谱联用(HPLC-MS)分析,菌株DY-9的表面活性产物为环状脂肽类表面活性剂.     

一株表面活性剂产生菌的分离及抑菌活性

【目的】研究分离得到的表面活性剂产生菌的产表面活性剂能力、分类地位和抑菌活性。【方法】采用血平板、油平板进行表面活性剂产生菌的分离,以排油圈法进行表面活性的测定;通过生理生化特性和16S rDNA序列相似性分析对BS1菌株进行初步鉴定;利用对峙培养法和菌丝生长、孢子囊形成、孢子萌发的抑制率测定研究其抑菌活性。【结果】从石油污染土壤中分离到的BS1菌株可产生表面活性剂,在分类学地位上属于假单胞菌属(Pseudomonas sp.)。BS1菌体、发酵上清液、挥发性物质对12种供试病原真菌均表现出一定的抑制作用。BS1菌体、发酵上清液对大豆疫霉菌(Phytophthora sojae)的抑制率最大,分别达到65.31%和95.93%。发酵上清液通过影响大豆疫霉菌菌丝生长、孢子囊形成、孢子萌发等方式抑制病原菌的正常生长,稀释20倍的发酵上清液依然具有明显的抑制作用。BS1菌株产生的挥发性物质对大豆菌核菌(Sclerotinia sclerotiorum)的抑菌效果最好,抑制率达到84.25%。【结论】BS1菌株在产生表面活性剂的同时,还具有生物防治作用潜力。     

Serrawettins:黏质沙雷氏菌合成的脂肽类生物表面活性剂

沙雷氏菌属的菌株可产生种类丰富的生物表面活性剂,如serrawettins、rubiwettins以及鼠李糖脂等.Serrawettins是由黏质沙雷氏菌(Serratia marcescens)合成的脂肽类生物表面活性剂,根据分子中氨基酸或肽组分的差异,serrawettins又可分为serrawettin W1、s...     

Dietzia natronolimnaios sp. nov., a new member of the genus Dietzia isolated from an East African soda lake

Two novel alkaliphilic aerobic organotrophic bacteria have been isolated from a moderately saline and alkaline East African soda lake. The new isolates grow at pH values between 6 and 10, with a pH optimum for growth of 9.0, and at a salt concentration between 0% and 10% (w/v). Phylogenetic analysis based on 16S rDNA sequence shows that these isolates are very closely related (99.6% similarity) and are members of the monospecific genus Dietzia (98.8% and 98.7% similarity). DNA/DNA hybridization revealed a relatedness of 83% between the two isolates, but only 8% between them and the type strain Dietzia maris. The G + C content as measured by thermal denaturation is 66.1 mol%. Phenotypic comparisons between D. maris and one isolate showed that they share very similar morphological and chemotaxonomic properties, but differ significantly in carbon source utilization profiles and halotolerance in alkaline medium. We propose a second species of this genus which we name Dietzia natronolimnaios (type strain 15LN1 = CBS 107.95). Received: October 14, 1997 / Accepted: February 26, 1998     

Dietzia sp. S-JS-1利用废弃油脂生产生物破乳剂的研究

生物破乳剂是近期开发出来的用于油水分离的新型破乳剂。本研究利用从受石油污染的土壤中筛选得到、并采用16S rRNA鉴定为Dietzia sp.的一株破乳剂产生菌, 在以废弃油脂MWFO、SWFO为碳源培养下, 得到的生物破乳剂的粗重为4 g/L、3.5 g/L; 对于W/O、O/W模型乳状液的破乳效果均可超过以液体石蜡产生的破乳剂, 且以SWFO废弃油脂培养得到的生物破乳剂可以同时应用于两种模型乳状液的使用。对于碳源利用方面Dietzia sp.在利用两种废弃油脂脂肪酸的过程中, 都是优先利用C16和C18的脂肪酸, 但对于两种废弃油脂的利用率上存在一定差异。采用TLC和FTIR分析发现, 3种碳源培养得到的生物破乳剂均为脂肽类生物破乳剂, 其破乳剂的化学结构还有待进一步研究。     

Isolation and structural characterization of biosurfactant produced by an alkaliphilic bacterium Cronobacter sakazakii isolated from oil contaminated wastewater

Production of biosurfactant from an alkaliphilic bacterium Cronobacter sakazakii (accession no. JN398668) was screened by haemolytic assay, emulsifying activity and surface tension measurement. Biosurfactant, comprised of total sugars (73.3%), reducing sugars (1.464%), protein (11.9%), uronic acid (15.98%) and sulfate (6.015%), showed low viscosity with pseudoplastic rheological behavior and exhibited significant emulsification activity with oils and hydrocarbons. A series of low and mid range mass peaks (m/z) corresponding to mono-, di-, tri- and oligosaccharides were detected in the positive ion reflector mode of MALDI TOF-TOF MS. GC-MS analysis revealed composition of monosaccharide moieties (w/w) viz. glucose (14%), mannose (24%), galactose (14%), xylose (20%) and arabinose (1.9%). ¹H NMR, FT-IR and EDX analyses confirmed the characteristic various functional groups, bonds and elements respectively. Thermostability (up to 260 °C) and CI (0.456) were determined by TG and DSC analyses. Inherent properties of biosurfactant make it a potential candidate for bioremediation of oil and hydrocarbons.     

Dietzia sp.S-JS-1利用煎炸废油生产生物破乳剂及其性能研究

以前期研究中筛选得到的破乳剂产生菌Dietzia sp.S-JS-1为研究对象,采用煎炸废油为培养碳源,考察菌株的生物量和表面张力,研究处理方式、温度、乳状液pH对破乳剂在两种模型乳状液W/O型(water in oil)和O/W型(oilin water)中破乳性能的影响,并初步分析生物破乳剂成分。结果表明:菌株最大生物量为2.6 g/L,其产生的破乳剂能够将纯水表面张力从72.0 mN/m降低到32.5 mN/m。冻融对破乳剂效果的影响小于高温灭菌;破乳剂经冷冻干燥处理后的破乳效果明显好于烘干处理;破乳剂在35℃～75℃时具有较好的破乳效果,脱水率均在75%以上;破乳剂在W/O型乳状液中的效果随着pH变大而逐渐增加,pH=10时的脱水率高达99.8%,而在O/W型乳状液中,pH=7时的脱水率最高,为90%左右。薄层色谱结果表明S-JS-1利用煎炸油生产的生物破乳剂可能含有5种脂肽类物质。     

Microbial degradation of disodium terephthalate by alkaliphilic Dietzia sp. strain GS-1

An alkaliphilic Dietzia sp., strain GS-1, which degraded disodium terephthalate (DT), was isolated from soil. Strain GS-1 degraded 19.3 mM of DT in 168 h at pH 10. The maximum degradation velocity was 0.46 mM/h. The resting cells efficiently degraded 28.7 mM of DT in 51 h at 28 degrees C and pH 10. The degradation velocity was 0.41 mM/(h g-wet cell).     

Properties of alkaliphilic halophiles

Summary Microorganisms capable of growth under highly alkaline conditions have been isolated from natural habitats. The isolation process utilized pH levels of 9.7 to 11.0, salts of 4.0 to 5.0%, temperatures of 45–50°C, and anaerobic conditions. Four isolates are described as gram-positive, spore-forming, motile, catalase-positive rods. This indicates that they are in the genusBacillus. The culture characteristics of these and two other isolates were evaluated. All six strains tolerated up to 11.0% salts in the growth medium. The purpose of this study was to evaluate these microorganisms for their potential use in combination with an alkaline flood for enhanced oil recovery. Useful products in in situ microbial-enhanced oil recovery include gases, surfactants, polymers and acids. The best gas producer wasBacillus strain ACP-1 which evolved an average of 2.11 ml gas per ml medium in 96 h.Bacillus strain ACP-1 reduced the surface tension of the growth medium from 50.3 mN/m to an average of 44.1 mN/m. Another aspect of this research project included investigation of the movement of these microbes through a porous medium. Various synthetic surfactants were found to improve movement through a porous system, while other surfactants improved gas production.     

Identification and biodegradation potential of a novel strain of Dietzia cinnamea isolated from a petroleum-contaminated tropical soil

A bacterial strain, named P4, isolated previously from microcosms containing oil-contaminated soil collected from an environmentally protected area of a tropical Atlantic forest (Biological Reserve of Poço das Antas) located in Brazil was identified as Dietzia cinnamea by morphological, biochemical and genotypic tests. Arabian Light and Marlin oils were both degraded when strain P4 was tested for oil degradation ability in microplates. Total Petroleum Hydrocarbons (TPH) analysis, determined by gas chromatography, showed that strain P4 degraded a wide range of n-alkanes, and also pristane and phytane. Furthermore, this strain was also able to grow in mineral liquid media amended with carbazole, quinoline, naphthalene, toluene, gasoline and diesel as the sole carbon sources. The species D. cinnamea has been previously described with only one representative strain isolated from a perianal swab of a patient with a bone marrow transplant. With the results presented here this species is implicated not only as a human pathogen but also as a potential strain for further studies concerning its role for bioremediation of oil contaminated soil.     

生淀粉酶生产菌株Paenibacillus sp.的筛选和酶的纯化及酶学性质

分离得到1株产生淀粉酶的菌株,通过扩增和测定16S rDNA序列并进行比对,发现是Paenibacillus属的细菌。液体摇瓶发酵结束后,其产生的生淀粉酶比酶活达108.5U/mL。通过饱和(NH4)2SO4沉淀、Sephacryl S-300层析的方法对其所产的生淀粉酶进行分离纯化,得到纯化的酶蛋白比酶活为5112.04U/mg,纯化倍数为14.1,相对分子质量约为1.0×105。该酶以木薯生淀粉为底物时,最适pH5.6,最适温度50℃。金属离子Ca2+、Mg2+对该酶具有激活作用,Zn2+、Cu2+、Fe2+、Ni2+、Mn2+、Co2+和EDTA2-对该酶均具有抑制作用。     

Sequencing of three lambda clones from the genome of alkaliphilic Bacillus sp. strain C-125

The nucleotide sequences of three independent fragments (designated no. 3, 4, and 9; each 15–20 kb in size) of the genome of alkaliphilic Bacillus sp. C-125 cloned in a λ phage vector have been determined. Thirteen putative open reading frames (ORFs) were identified in sequenced fragment no. 3 and 11 ORFs were identified in no. 4. Twenty ORFs were also identified in fragment no. 9. All putative ORFs were analyzed in comparison with the BSORF database and non-redundant protein databases. The functions of 5 ORFs in fragment no. 3 and 3 ORFs in fragment no. 4 were suggested by their significant similarities to known proteins in the database. Among the 20 ORFs in fragment no. 9, the functions of 11 ORFs were similarly suggested. Most of the annotated ORFs in the DNA fragments of the genome of alkaliphilic Bacillus sp. C-125 were conserved in the Bacillus subtilis genome. The organization of ORFs in the genome of strain C-125 was found to differ from the order of genes in the chromosome of B. subtilis, although some gene clusters (ydh, yqi, yer, and yts) were conserved as operon units the same as in B. subtilis. Received: April 17, 1998 / Accepted: June 23, 1998     

一株抗万古霉素耐药菌的抗生素产生菌AR1148的鉴定

从土壤中分离得到一株放线菌AR1148,其代谢产物对万古霉素耐药肠球菌有较明显的抑菌活性。该菌株的基内菌丝无横隔,气生菌丝丰茂,分枝较好,孢子椭圆形,表面光滑。菌丝细胞壁工型,含有L-2,6-二氨基庚二酸（LL-DAP）和甘氨酸。菌株AR1148归属于链霉菌属金色类群。根据16SrDNA序列分析,该菌株与现有种差异明显,聚类在不同的分支。定名为Streptomyces sp．AR1148。