富里酸诱导对三角褐指藻EPA合成积累的影响

探究不同富里酸质量浓度对三角褐指藻二十碳五烯酸(EPA)合成积累的影响。结果表明，在质量浓度20 mg/L富里酸诱导下，三角褐指藻EPA含量和产量均达到最大值，为19.81 g/100 g和738.91 mg/L，较无富里酸诱导EPA含量和产量分别提高1.12和1.50倍。外源富里酸作用提高了三角褐指藻胞内过氧化物酶(POD)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)的酶活，使色素(叶绿素、类胡萝卜素)和总多酚抗氧化组分比例增加，活性氧(ROS)和丙二醛(MDA)水平降低，整体抗氧化能力获得显著提升，有效阻抑EPA的氧化分解；富里酸作用同时还上调了EPA合成通路去饱和酶(Δ⁵-FADS、Δ⁶-FADS、Δ¹²-FADS、Δ¹⁵-FADS、Δ¹⁷-FADS)和延长酶(Δ⁶-ELOVL)等系列关键酶，使其上调表达量较无富里酸作用分别增加0.33、0.94、0.33、0.58、1.15和0.70倍，为EPA高效合成积累提供前驱物和能量。     

营养元素对三角褐指藻生长和脂类积累的影响

研究了不同营养元素(氮、磷、硅、铁)在不同培养浓度条件下,对三角褐指藻生长以及细胞脂类积累的影响作用。结果显示:藻细胞生长随氮含量的增加而增加,但超过一定浓度后作用不明显,最适合三角褐指藻生长的氮含量为 1.76 mmol/L。缺氮和低氮(0.22~0.44 mmol/L)培养能够明显提高藻细胞脂类含量。缺磷培养能有效促进藻株脂类积累,但是藻细胞生长受到明显抑制。缺硅导致藻细胞的生长减缓,但是对藻细胞的油脂积累影响不显著。在缺铁和高铁(0.048 mmol/L)条件下,藻的总脂含量均高于正常的培养条件。实验证明通过两步培养的方法,先在营养充足的培养基中进行藻细胞生长,然后将藻细胞转移到海水中培养,可以明显提高藻细胞的油脂含量。最终本实验确定海水为诱导三角褐指藻脂类积累的最佳诱导培养基。     

二乙醇胺强化胶球藻Coccomyxa subellipsoidea C-169固定CO2和积累油脂

以优良藻株胶球藻Coccomyxa subellipsoidea C-169为受试对象,探究不同二乙醇胺（DEA）浓度对胶球藻固定CO₂及积累油脂的影响。结果表明,适宜浓度DEA可显著提高胶球藻固定CO₂和积累油脂效率。在40mg/L DEA条件下,胶球藻生物量、CO₂固定效率、油脂含量、油脂产率均达到最大值为0.97g/L、225.98mg/(L·d)、64.33%、59.9mg/(L·d),分别较无DEA对照提高了1.64倍、1.64倍、1.15倍和1.27倍。外源DEA作用提高了体系气液传质系数,增强CO₂传质效率,使得胶球藻可用无机碳源比例增加,同时上调固碳路径Rubisco和CA加强胶球藻固定CO₂,上调脂肪酸路径ACCase以及下调ACCase竞争路径PEPC为油脂合成积累提供前体和能量,从而协同强化了胶球藻固定CO₂和积累油脂。本文研究结果为工业化胶球藻CO₂生物减排及可再生能源开发提供依据。     

烯酰还原酶基因的替换对裂殖壶菌合成二十碳五烯酸的影响

二十碳五烯酸（eicosapentaenoic acid,EPA）因具有调节血脂、降低纤维蛋白、预防心血管疾病以及抗炎抗过敏的生理功能,被广泛应用于食品、医疗、化妆品以及饲料添加等领域。目前,EPA的需求日益增加,但是富含多不饱和脂肪酸（polyunsaturated fatty acids,PUFAs）的鱼油等自然资源逐渐匮乏,利用改造的微生物菌种发酵生产EPA的方式成为主要趋势。本研究利用同源重组技术将Shewanella sp. SCRC2738的烯酰还原酶基因（enoyl-reductase,sh-ER）分别敲入Schizochytrium limacinum SR21的ORFB-ER和ORFC-ER基因中,调控多不饱和脂肪酸合成的偏好性以提高EPA的产量。研究表明,sh-ER替换ORFB-ER基因的重组菌株（B-sh-ER）中EPA含量提高了85.7%,聚酮合酶（polyketide synthases,PKS）途径相关基因转录水平明显上调。而sh-ER替换ORFC-ER基因的重组菌株（C-sh-ER）中PUFAs合成基本不变。在5 L发酵罐中放大培养后,B-sh-ER重组菌株总油脂提高28.7%,达到73.2 g/L;EPA产量提高71.6%,达到732.4 mg/L。本研究为促进裂殖壶菌PUFAs高产提供了新的策略,同时也为调控裂殖壶菌合成EPA提供了新的视角。     

海水小球藻和三角褐指藻对U(Ⅵ)的吸附研究

以冷冻干燥法制备海水小球藻和三角褐指藻藻粉,考察pH、时间、温度、初始U(Ⅵ)浓度、盐浓度等对两种微藻在水溶液中吸附U(Ⅵ)的影响,并由Langmuir模型拟合结果分析得出海水小球藻和三角褐指藻对U(Ⅵ)的吸附量最高分别达1 314.0 mg/g和1 450.0 mg/g。采用BM、SEM、EDS、FTIR等方法对两种微藻吸附U(Ⅵ)前后形貌及结构进行表征,分析可能存在的吸附机理。此外,模拟深海高压环境考察藻粉对U(Ⅵ)的吸附,得出2种藻粉在一定超高压环境下U(Ⅵ)吸附性能良好,且三角褐指藻优于海水小球藻。     

通气量和CO2对Nannochloropsis sp.在光生物反应器中的生长和EPA合成的影响

实验考察了在气升式内环流光生物反应器中通气量、CO2含量等培养条件对Nannochloropsis sp.生长及EPA合成的影响. 结果表明,在气升式内环流光生物反应器中培养,Nannochloropsis sp.生长速率显著提高. 培养8 d,Nannochloropsis sp.生物量(干重)可达857 mg/L,是摇床培养的2倍. 在一定范围内,Nannochloropsis sp.的生长速率随通气量的增加而增加,在本实验条件下,通气量为500 mL/min时生长最快,而过高的通气量则对Nannochloropsis sp.的生长没有促进作用. 在通气中含1%(j) CO2时,可加快藻细胞的生长,最大生长速率可达不配加CO2时的1.8倍. 通气量和CO2对Nannochloropsis sp.细胞内总脂肪酸及EPA的积累有显著影响. 在通气量为400 mL/min及CO2含量为0.5%时,培养液中EPA产量最高,达到39.0 mg/L.     

新型天然活性物修护肌肤机理分析

简要介绍了皮肤羰基化反应的诱因,重点从皮肤中蛋白质羰基化产生机理分析了其对人体肌肤产生的不良反应.讨论了蛋白质的降解系统,最后根据蛋白质的羰基化产生机理以及降解方式,提出建议解决方案:二葡糖基棓酸、玫瑰茄花提取物、欧洲酸樱桃花提取物可以通过降低ROS含量和三角褐指藻提取物提高20S酶体活性加速羰基化蛋白质水解水平降低人...     

褐煤粒度对碱法制备胡敏酸和富里酸的影响

以不同粒度的白音华褐煤碱性煤浆为原料,5%(质量分数,下同)NaOH溶液和1 mol/L H2SO4溶液为pH值调节剂,制备胡敏酸和富里酸。通过容量法和紫外可见分光光度法分析胡敏酸和富里酸的含量、提取率、E4/E6值和DPPH(1,1-二苯基-2-三硝基苯肼)抗氧化活性,探讨褐煤粒度对胡敏酸和富里酸的影响规律。结果表明:当褐煤粒度减小到13.28μm时,胡敏酸和富里酸的总提取率为86.34%,胡敏酸与富里酸的分子量和芳香缩合度最为相似。该粒度条件下,富里酸的提取率可达62.28%,游离腐植酸质量分数为47.4%,DPPH自由基清除率为41.3%,富里酸的抗氧化活性显著。     

要闻链接

仙婷(中国)有限公司代理的三角褐指藻提取物正式投放市场仙婷(中国)有限公司(SETHICCHINA)(www seth ic china.com)于2004年10月19日在广州正式宣布向市场投放三角褐指藻提取物(Thalassane) ,它是由克里斯汀 迪奥(ChristianDior)研究中心开发的微藻类提取物 ,其功效是使皮肤恢复到年轻时的状态。三角褐指藻提取物是通过一种新颖的作用机理发挥其功效的 ,那就是“泛素调节的蛋白质降解” ,也正是这个机理使其发现者(以色列科学家阿龙·切哈诺沃、阿夫拉姆·赫什科和美国科学家欧文·罗斯)在2004年10月6日获得了诺贝尔化学奖。在20世纪…     

富里酸络氨铜的合成与表征

针对富里酸在农业上的重要作用,合成一种兼具富里酸和铜离子优点的富里酸络氨铜(FA-Cu),将其应用到农作物肥料中,达到绿色环保、低成本的优点。本文采用单因素和正交试验的方法,研究了pH值、富里酸浓度、硫酸铜浓度等因素对合成富里酸络氨铜的质量、纯度、颗粒均匀程度的影响。结果表明:富里酸浓度为3%,硫酸铜浓度为4%,pH值为7时为最佳合成条件,此条件下合成的富里酸络氨铜沉淀颗粒体积较小、分布均匀、没有团簇现象,并通过红外光谱分析和热重分析对产物进行了表征,分析结果表明合成了富里酸络氨铜。     

Oxidative stability of soybean oils with altered fatty acid compositions

The oxidative stabilities of one canola oil and six soybean oils of various fatty acid compositions were compared in terms of peroxide values, conjugated dienoic acid values and sensory evaluations. Two of the soybean oils (Hardin and BSR 101) were from common commercial varieties. The other four soybean oils were from experimental lines developed in a mutation breeding program at Iowa State University that included A17 with 1.5% linolenate and 15.2% palmitate; A16 with 2% linolenate and 10.8% palmitate; A87-191039 with 2% linolenate and 29.6% oleate; and A6 with 27.5% stearate. Seed from the soybean genotypes was cold pressed. Crude canola oil was obtained without additives. All oils were refined, bleached and deodorized under laboratory conditions with no additives and stored at 60°C for 15 days. The A17, A16, A87-191039 and A6 oils were generally more stable to oxidation than the commercial soybean varieties and canola oil as evaluated by chemical and sensory tests. Canola oil was much less stable than Hardin and BSR 101 oils by both chemical and sensory tests. The peroxide values and flavor scores of oils were highly correlated with the initial amounts of linolenate (r=0.95, P=0.001). Flavor quality and flavor intensity had negative correlations with linolenate, (r=−0.89, P=0.007) and (r=−0.86, P=0.013), respectively.     

天然脂肪酸及其聚合物

简介天然脂肪酸的性质及国内外的生产、消耗水平；重点介绍一烯酸中的油酸的来源、古量、用途，还介绍天然脂肪酸聚合物二聚酸的结构、性质、生产工艺、品种、质量、用途、市场等。     

气相色谱法测定化妆品中脂肪酸含量

建立了气相色谱法检测化妆品中脂肪酸(十二酸、十四酸、十六酸、十八酸)。采用HP-5毛细管柱,研究脂肪酸甲酯化及气相程序升温的参数,得到了应用保留时间和峰面积对脂肪酸进行定性定量的方法。结果表明,此方法参数可以使化妆品中的脂肪酸得到很好分离,具有较高的准确性和重复性,线性相关系数均为1,测定结果与实际添加量的偏差在2%以内。     

脂肪酸甘油酯磺酸盐的合成

以α-磺酸脂肪酸甲酯和甘油为原料,经酯交换及中和反应合成了脂肪酸甘油酯磺酸盐。得到较佳的反应条件为:四氯化碳作溶剂,n(α-磺酸脂肪酸甲酯)∶n(甘油)=1∶5,75℃反应4 h,高效液相色谱分析α-磺酸脂肪酸甲酯的转化率可达66.33%。采用红外光谱和质谱确证了脂肪酸甘油酯磺酸盐的结构,结果表明,反应产物中除了含有单脂肪酸甘油酯磺酸盐外,还含有脂肪酸甲酯磺酸盐和二脂肪酸甘油酯磺酸盐。     

生物柴油在精细化学品领域的应用

论述了生物柴油(即脂肪酸甲酯)代替脂肪酸在制造精细化工品上的优势,并列举了生物柴油在表面活性剂工业、塑料助剂、醇酸树脂、皮革化学品上的应用。指出了用生物柴油代替脂肪酸具有成本低廉、工艺简化的优点,并可提高生物柴油的应用价值,具有广阔的应用前景。     

Digestibility of fatty acid monomers,dimers and polymers in the rat

This study was designed to determine digestibilities of fatty acid monomers, dimers and polymers as components of diets containing thermally oxidized oils. Male Wistar rats were fed semipurified diets supplemented with unheated, heated and a 1:1 mixture of unheated/heated olive oils at 6, 12 and 20% w/w of diet. In a 14-d experimental period, fecal lipids were extracted and analyzed by a combination of adsorption and high-performance size-exclusion chromatographies. Thus, it was possible to separate and quantitate five groups of fatty acids—nonpolar monomers, oxidized monomers, nonpolar dimers, oxidized dimers and polymers. Nonpolar fatty acid monomers showed high digestibilities, although significantly influenced by the alteration level of the dietary oil. The apparent absorption of oxidized fatty acid monomers averaged 76.6%. Among polymeric fatty acids, the lowest digestibilities were found for nonpolar dimers (10.9% on average), whereas oxidized dimers and polymers possessed higher apparent absorbability than expected, ranging from 22.7% to 49.6%. Chemical modifications prior to absorption, leading to less complex products, may have contributed to enhanced digestibility of polymers.     

Determination of vernolic acid content in the oil ofEuphorbia lagascae by gas and supercritical fluid chromatography

Determination of the content of vernolic acid (12,13-epoxy-9c-octadecenoic) in the oil ofEuphorbia lagascae has been performed by gas chromatography of the fatty acid methyl ester derivatives of the triacylglycerols in the oil and by supercritical fluid chromatography (SFC) of the raw oil and the fatty acid derivatives of the oil. The content of vernolic acid was found to be 55 wt%. The three methods were compared, and SFC analysis of the fatty acid derivatives was found to be the most accurate method.     

Simultaneous Determination of Free Fatty Acids and Esterified Fatty Acids in Rice Oil by Gas Chromatography

Free fatty acids (FFA) in crude rice oil were selectively and stoichiometrically derivatized to fatty acid N,N-dimethylamides (FADMA) by catalytic condensation at 45 °C, and then esterified fatty acids (eFA) were directly converted to fatty acid methyl esters (FAME) at 37 °C. The mixture of FADMA and FAME formed in a single test tube was injected into the capillary column of a gas chromatograph (GC). No mutual contamination occurred between FFA and eFA, and reliability of the method was confirmed by comparison between GC data obtained by this method and by a conventional isolation method. The advantages of the present method are that no FFA isolation procedures are required, the reactions proceed under mild temperature conditions, and FFA and eFA can be analyzed simultaneously by GC.     

Stabilisation of the Fatty Acid Decarboxylase from Chlorella variabilis by Caprylic Acid

The fatty acid photodecarboxylase from Chlorella variabilis NC64 A (CvFAP) catalyses the light-dependent decarboxylation of fatty acids. Photoinactivation of CvFAP still represents one of the major limitations of this interesting enzyme en route to practical application. In this study we demonstrate that the photostability of CvFAP can easily be improved by the administration of medium-chain length carboxylic acids such as caprylic acid indicating that the best way of maintaining CvFAP stability is ‘to keep the enzyme busy’.