岷山毛建草挥发油化学成分分析

利用气相色谱 质谱联用技术对岷山毛建草的挥发油成分进行分析 ,共鉴定出 6 1种组分。其中主要成分为十六烷酸、十六烷酸乙酯、3 ,5 双烯 豆甾烷、N ,N 二苯基 [1,1 联苯 ] 4,4′肼、邻苯二甲酸二丁酯、二十七烷、二十九烷、三十二烷、十八烷酸乙酯、二十二烷酸乙酯等 ,其中十六烷酸和十六烷酸乙酯的含量较高 ,占挥发油成分总量的 14 2 %。检出成分占挥发油成分的 6 3 3%。     

燕子掌挥发油化学成分的研究

应用气象色谱-质谱联用技术对燕子掌挥发油化学成分进行了分析研究,共鉴定出66种组分与燕子掌主要挥发性化学成分以苯乙醇、2,6,6-三甲基-2,4-环庚二烯-1-酮、6,10,14-三甲基十五烷-2-酮、十六烷酸甲酯、十六烷酸乙酯、十八烷酸甲酯为主要成分,化合物类型以酮、酯、类等化合物为主,其中十六烷酸甲酯的含量最高,占挥发油总量的26．13％。     

云南干巴菌挥发油化学成分的研究

利用气相色谱－质谱联用技术对云南干巴菌的挥发油化学成分进行了研究,共鉴定出49种组分。其中主要成分为业油酸甲酯、棕榈酸、1,1－二乙氧基乙烷、苯乙醛、十六碳烯酸、十五烷酸、邻苯二甲酸二丁 、苯甲酸、苯乙醇、硬脂酸、二十一烷、肉豆蔻酸、十八碳烯酰胺、苯乙酸等,其中亚油酸甲酯的含量最高,占挥发油成分总量的27.12％,检出成分占挥发油总量的90％。     

豺皮樟叶挥发油化学成分的研究

利用GC－MS联用技术从豺皮樟（Litsea rotundifolia var.oblongifolia)叶挥发油中分离和鉴定了27个化合物,占挥发油总量的88．75％,其中主要成分是十二烷酸（43．68％）,肉豆蔻酸（14．61％）,十一烷酸（4．70％）,棕榈酸（4．15％）。     

广藿香根与根茎挥发油成分研究

应用气相色谱－质谱联用技术对广藿香根和根茎中挥发油成分进行了分析,从根油中分离出５０个色谱峰,鉴定了４７个化合物,占总量的９５．０２％,主要含广藿香酮（８１．７１％）、ｄ－苦橙油醇（２．８８％）、十六烷酸（２．２１％）、广藿香醇（１．９８％）和３,７,１１－三甲基－２,６,１０－十二烷三烯－２－醇乙酸酯（１．０９％）、广藿香醇（１．９８％）和３,７,１１－三甲基－２,６,１０－十二烷三烯－１－醇乙     

云南丛生树花净油的组成：1.主要的脂肪酸乙酯

根据气相色谱-质谱数据推定云南丛生树花净油液体部分中四种主要成分为辛酸乙酯、十六烷酸乙酯、十八烷酸乙酯和2,4,6-十八碳三烯酸乙酯。     

蝴蝶果茎挥发油的化学成分

采用水蒸汽蒸馏法从大戟科蝴蝶果茎中提取挥发油,用气相色谱-质谱联用技术对挥发油化学成分进行分析。分离出36个峰,鉴定出35种化合物,占总油量的98.34%,并应用面积归一化法测定各成分的相对百分含量。其主要成分为十六烷酸乙酯(13.19%)、正十六烷酸(11.11%)、十八碳烯酸乙酯(6.18%)、正十八烷(4.98%)、(Z,Z)-9,12-十八碳二烯酸(4.90%)及十八碳二烯酸乙酯(4.21%)。     

鸡屎藤挥发油化学成分的研究

利用气相色谱－质谱联用（ＧＣ／ＭＳ）技术对鸡屎藤挥发油化学成分进行分析研究,初步鉴定了３１种成分,它们占挥发油总量的７７．１６％,其中含量友上的有乙氧戊烷、乙酸异戊酯、苯甲醛、己酸乙酯、甲酸苯甲酯、乙酸苯甲酯、乙酸－２－苯乙酯、５,６,７,７ａ－四氢－４,４,７ａ－三甲基－２（４Ｈ）－苯并呋喃酮、十五碳酸乙酯、十六碳酸和癸酸异戊酯等１１种成分。     

藏药短管兔耳草挥发性化学成分的研究

采用毛细管气相色谱—质谱联用技术对藏药短管兔耳草挥发性化学成分进行了研究,经毛细管色谱分离出62个峰,共确定了其中41种化学成分,所鉴定的化合物含量占全挥发油的77．32％;用气相色谱面积归一化法测定了各化学成分的相对含量,其主要化学成分为：二苯胺(16．47％)、邻苯二甲酸丁基—8—甲基壬基酯(6．42％)、二十六碳烷(4．76％)、十六烷酸(3．66％)、二十四碳烷(3．40％)、邻苯二甲酸二丁酯(3．38％)、二十二碳烷(3．30％)、二十碳烷(3．26％)、十六烷酸乙酯(2．77％)、十八碳烷(2．76％)、戊酸(2．48％)、3—乙基环辛烯(2．05％)等。     

云南使君子仁油化学成分的GC-MS分析

以常规溶剂萃取得使君子仁油,取两份油,一份经甲酯化处理,别一份不甲酯化,然后采用重量法和气相色谱-质谱联用技术分别测定使君子仁油含量和脂肪酸成分。结果表明：使君子仁油含量为15％;从甲酯化脂肪油中共检测出5种成分,其中E-9-十八烯酸占脂肪酸总量的46．99％,十六烷酸甲酯占脂肪酸总量的28．25％;另外,从未甲酯化脂肪油中共检测出7种成分,其中含防十八烯酸63．19％,十六烷酸甲酯15．26％,同时还检测出11．79％的γ-生育酚。使君子仁油是具有抗氧化性的植物源脂肪油,是开发和利用E-9-十八烯酸,十六烷酸甲酯和γ-生育酚的理想原料,在食用、医疗保健方面具有巨大潜力和广阔前景。     

Enrichment of pinolenic acid from pine nut oil via lipase-catalyzed ethanolysis with an immobilized Candida antarctica lipase

Abstract

Pinolenic acid (PLA) enrichment as an ethyl ester from pine nut oil was successfully accomplished in a batch reactor by lipase-catalyzed ethanolysis using Novozym 435 lipase from Candida antarctica as a biocatalyst. PLA is predominantly an sn-3 substituent of the pine nut oil triacylglycerol (TAG), where it accounts for about 39 mol% of the fatty acids esterified at that position. In the presence of ethanol, Novozym 435 exhibited sn-3 regiospecificity with respect to the TAG of pine nut oil. The effect of the molar ratio of reactants on PLA enrichment by ethanolysis was investigated. The molar ratios of pine nut oil to ethanol were varied from 1:20 to 1:100. A fatty acid ethyl ester (FAEE) fraction with higher PLA content was obtained in the early stage of the reaction, although the yield of PLA was small. However, the PLA content of the FAEEs decreased with increasing reaction time, while the yield of PLA increased. The molar ratio of pine nut oil to ethanol that produced the optimum content and yield of PLA in FAEEs was 1:80.     

Effect of frying time on free fatty acid generation and esterification rate in Aspergillus sp.-catalyzed transesterification of cottonseed oil

Abstract

The present study was carried out to examine the effect of different frying times of edible oil on the extent of transesterification catalyzed by the whole-cell biocatalyst, Aspergillus (RBD01). Cottonseed oil was chosen as a conventional and cost-effective edible oil used commercially in India. The results showed that increased frying time of the oil decreased the extent of the transesterification reaction and hence alkyl ester production. Nearly complete (>98%) transesterification to ethyl alcohol was observed with used oil containing a free fatty acid (FFA) content of 3.7%, whereas beyond an FFA content of 4.0% the yield was reduced. Biocatalyzed hydrolysis (in the absence of the ethyl alcohol acceptor) of used frying oil resulted in decreasing yield of FFA from 84.0% to 27.6% with increasing frying time. With fried oil capable of a hydrolysis yield of 82–41% FFA, transesterification reactions were nearly complete. With the lower hydrolysis yields of 38–27% FFA, the transesterified ethyl ester yield decreased to 61–51%. These observations indicate that factors other than the presence of FFA and moisture influence the biocatalytic transesterification of used cooking oils.     

Enantioselective microbial reduction of 3,5-dioxo-6-(benzyloxy) hexanoic acid, ethyl ester

The key chiral intermediate 3,5-dihydroxy-6-(benzyloxy) hexanoic acid, ethyl ester 2a, was made by the stereoselective microbial reduction of 3,5-dioxo-6-(benzyloxy) hexanoic acid, ethyl ester 1. Among various microbial cultures evaluated, cell suspensions of Acinetobacter calcoaceticus SC 13876 reduced 1 to 2a. The reaction yield of 85% and optical purity of 97% was obtained using glycerol-grown cells. The substrate was used at 2 g l⁻¹ and cells were used at 20% (w/v, wet cells) concentrations. The optimum pH for the reduction of 1 to 2a was 5.5 and the optimum temperature was 32°C. Cell extracts of A. calcoaceticus SC 13876 in the presence of NAD⁺, glucose, and glucose dehydrogenase reduced 1 to the corresponding monohydroxy compounds 3 and 4 [3-hydroxy-5-oxo-6-(benzyloxy) hexanoic acid ethyl ester 3, and 5-hydroxy-3-oxo-6-(benzyloxy) hexanoic acid ethyl ester 4]. Both 3 and 4 were further reduced to 2a by cell extracts. Reaction yield of 92% and optical purity of 99% were obtained when the reaction was carried out in a 1-l batch using cell extracts. The substrate was used at 10 g l⁻¹. Product 2a was isolated from the reaction mixture in 72% overall yield. The GC and HPLC area % purity of the isolated product was 99% and the optical purity was 99.5%. The reductase which converted 1 to 2a was purified about 200-fold from cell extracts of A. calcoaceticus SC 13876. The purified enzyme gave a single protein band on SDS-PAGE corresponding to 35,000 daltons.     

Assessment of bacterial acyltransferases for an efficient lipid production in metabolically engineered strains of E. coli

Microbially produced lipids like triacylglycerols or fatty acid ethyl esters are currently of great interest as fuel replacements or other industrially relevant compounds. They can even be produced by non-oleaginous microbes, like Escherichia coli, upon metabolic engineering. However, there is still much room for improvement regarding the yield for a competitive microbial production of lipids or biofuels. We genetically engineered E. coli by expressing fadD, fadR, pgpB, plsB and ‘tesA in combination with atfA from Acinetobacter baylyi. A total fatty acid contents of up to 16% (w/w) was obtained on complex media, corresponding to approximately 9% (w/w) triacylglycerols and representing the highest titers of fatty acids and triacylglycerols obtained in E. coli under comparable cultivation conditions, so far. To evaluate further possibilities for an optimization of lipid production, ten promising bacterial wax ester synthase/acyl-Coenzyme A:diacylglycerol acyltransferases were tested and compared. While highest triacylglycerol storage was achieved with AtfA, the mutated variant AtfA-G355I turned out to be most suitable for fatty acid ethyl ester biosynthesis and enabled an accumulation of approx. 500 mg/L without external ethanol supplementation.     

Maturation of Fermented Rice-koji Miso Can Be Monitored by an Increase in Fatty Acid Ethyl Ester

A mixture of steamed soybean and boiled rice with seeded Aspergillus oryzae was naturally fermented without addition of yeasts or Lactobacilli, and kept matured for 12 months at room temperature. Chemical analysis of this rice-koji miso sample for lipid changes during maturation showed that triacylglycerol was gradually decomposed into free fatty acid, with distinct formation of fatty acid ethyl ester which, six months after the start of fermentation, came to account for 35.0% of total lipid. The ester was constituted primarily with linoleic acid (ca. 50%) and oleic acid (ca. 20%), no appreciable change in this proportion being observed during maturation. Also, the proportion was unique in that this did not reflect the fatty acid composition in a mixture of the two materials. It is possible to monitor the maturation of the rice-koji miso by following up the increase with time in fatty acid ethyl ester.     

Studies on the Chemical Constituents of Rhodiola fastigita S. H. Fu

Rhodiola fastigita is an alpine plant growing at 3300--5400 m above sea level. Seven crystal, compounds were isolated from the rhizome of this plant. They were identified as β- sitosterol, β-sitosterol-3-β-D-galactoside, daucosterol, gallic acid, gallic acid ethyl ester, p-tyrosol and herbacetin-8-arabinoside by IR, MS, H-NMR and chemical method. Daucosterol, β-sitosterol- 3-β-D-galactoside and gallic acid ethyl ester were obtained from the genus Rhodiola L. for the first time.     

（S）-（-）-β-羟基苯丙酸乙酯的微生物法合成

采用酿酒酵母CGMCC No．2266菌体,不对称还原β-羰基苯丙酸乙酯制备光学纯（S）-（-）-β-羟基苯丙酸乙酯。结果表明：采用初始pH为8．0的液体发酵培养基培养的CGMCCNo．2266菌体经过50℃预热处理30min后用于生物转化获得的（S）-（-）-G-羟基苯丙酸乙酯对映体过剩值可以达到100％ee。确定了合成（S）-（-）-β-羟基苯丙酸乙酯的较佳转化条件为pH7．0,温度30℃,转化时间24h,底物浓度为3．63mmol／L,菌体用量为86g/L（干重／反应体积）。以10％葡萄糖为辅助底物,产率比不加辅助底物时提高了75．4％。在最佳转化条件下反应转化率及（S）-（-）-β-羟基苯丙酸乙酯对映体过剩值可分别达到98．4％和100％ee。     

产谷氨酰胺菌株的诱变育种

以黄色短杆菌为出发菌株 ,经过甲基磺酸乙酯化学诱变处理 ,最后得到 1株变异株CAW 1。经初筛、复筛和传代实验 ,表明其是稳定的变异株。其谷氨酰胺的产量由诱变前的 2 .86 %提高到 4.5 8% ,提高了 6 0 .1%。     

Surface films as mosquito larvicides: partitioning the mode of action

Oils and other surface films used against mosquito larvae may act by flooding the tracheal system with oil, by disrupting the surface forces that allow larvae to rest at the surface, by toxicity, or by eliciting chemosensory responses. In an attempt to identify diagnostic symptoms of these modes of action we treated fourth-stage larvae of Culex pipiens L. form molestusForskål (Diptera: Culicidae: Culicinae) with agents operating in a single mode (Ondina oil for flooding with oil, nicotine for toxicity, and the detergent Triton X-100 for disruption of surface forces), in two modes (silicone oil) or in three (eucalyptus oil, citronellal, or caproic acid ethyl ester). We monitored the time course of flooding and immobilisation, used experiments to separate volatile toxicity from toxicity of the aqueous solution, and used video and The Observer software to analyse larval behaviour.Larvae that experienced tracheal flooding applied their mouthparts to the siphon (tail nibbling), often losing contact with the surface while doing so and falling to the bottom. Nicotine immobilised larvae without interfering with surface forces, and the larvae remained immobile hanging from the air-water interface for long periods. In detergent, larvae made repeated unsuccessful attempts to thrust the siphon through the surface. The behaviour-modifying chemicals caproic acid ethyl ester, eucalyptus oil and citronellal all operated in more than one mode. They all decreased the proportion of time larvae spent at the surface, whereas Ondina oil and silicone fluid increased it.Using this approach it should be possible to identify the modes of action of novel larvicidal agents. This could form a basis for rational design of larvicides giving an optimal compromise between efficacy against mosquito larvae and minimal damage to non-target organisms.     

Inhibitory Activities of Aromatic Amino Acid Esters and Peptides against Ovalbumin Permeation through Caco-2 Cell Monolayers

Trp, Phe, and Tyr ethyl esters and their dipeptides with Gly at the C-terminals inhibited ovalbumin (OVA) permeation through Caco-2 monolayers. The inhibitory activity of Trp ethyl ester was the highest at near the concentration of 10^-6 M. It was suggested that Trp ethyl ester inhibited transcellular permeation of OVA.