Substrate specificity of the lipase fromCandida parapsilosis

Substrate specificity of the acyltransferase activity of the lipase (EC 3.1.1.3) fromCandida parapsilosis CBS 604 was studied in aqueous media. The specificity toward both acid and alcohol parts of a large number of acylglycerols and aliphatic esters was investigated. This lipase showed a high activity in the presence of esters with long-chain fatty acids and particularly unsaturated fatty acids with acis-Δ9 double bond. It was observed that the activity profile depended not only on the alcohol part of the acyl ester, but also on the temperature of the reactant medium. The best lipid substrates had their melting point between −40 to +20°C, 14 to 18 carbon atoms in the acyl group and 1 to 4 carbon atoms in the alkyl group. The enzyme, defined as an acyltransferase in a previous paper, showed a high affinity for primary and secondary alcohols with a short carbon chain (1 to 5 carbon atoms) as acyl acceptors. The influence of free alcohols in the reactant medium on the hydrolysis and alcoholysis activities of the enzyme is discussed. Two phenomena seem to be involved, depending on the alcohol: competition with water for the acyltransfer reaction and lipid substrate dilution when the alcohol places at the oil/water interface.     

Characteristics of the lipase fromCandida rugosa modified with copolymers of polyoxyethylene derivative and maleic acid anhydride

The hydrophilic copolymer, polyethylene oxide (PEO) allyl ester-maleic anhydride (MA), copolymer was used to modify the lipase from Candida rugosa. MA, in a functional group, reacts easily with amino acids of lipase. The degree of modification (DM) was varied by changing the weight ratio of copolymer to protein of lipase over the range of 10–120 (w/w). The specific activity decreased as DM increased. At the maximum modification degree of 35%, the modified lipase retained more than 65% of the unmodified native lipase activity. The modified lipase displayed a high stability of activity against temperature and pH. The remaining activity of modified lipase was about 2–4 fold of that of native lipase in the severe pH and temperature condition. Finally, it showed 20% greater reaction of substrate at 10 hr than in the case where native lipase was used.     

Preparation of active carbon from yeast

Results are given for laboratory production of activated carbon from yeast (Saccharomyces cerevisiae). The carbon was obtained by carbonization and simultaneous activation of the yeast cells previously impregnated with chemicals (H₃PO₄-K₂CO₃-ZnCl₂). The influence of the different activation conditions on development of porous structure was studied.     

羟甲基次膦酸的制备研究

本文介绍了羟甲基次膦酸的制备方法，提出利用普通的生产原料和设备合成羟甲基次膦酸和氯甲基膦酰氯的最佳工艺。     

Preparation of petroselinic acid

Petroselinic acid of a grade which is suitable for most laboratory applications has been prepared by a single crystallization of the mixed fatty acids of parsley seed oil from 90% ethanol. A product of higher purity has been prepared from this acid by application of urea segregation techniques for the removal of saturated materials. No evidence of the presence of unsaturated fatty acids other than petroselinic acid was found in either of these samples when their ozonolysis products were examined chromatographically. On the basis of iodine values, assuming the absence of other unsaturated materials, the purities of the two preparations are 96.0 and 99.4%. One of the laboratories of the Southern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.     

Peculiar properties of lipase fromCandida parapsilosis (Ashford) langeron and talice

A newCandida parapsilosis lipase was isolated and studied. This enzyme was purified by hydrophobic chromatography on a phenyl-sepharose CL4B column followed by gel permeation on a Sephacryl S300 HR column. It was a 160 kg·mol⁻¹ molecular-weight oligomeric enzyme. Optimal activity was obtained at 45°C and pH 6.5. The lipase activity toward various acylglycerols and esters was studied. The hydrolysis rate was greater for secondary acylesters than for primary acylesters. This lipase showed a high specificity for long-chain fatty acids and particularly for polyunsaturated fatty acids. This enzyme was able to catalyze the synthesis of various oleoylesters in aqueous medium.     

Preparation of linseed acid chlorides

A method is described for the preparation of linseed acid chlorides in excellent yields and functional purity. After linseed acids are reacted with phosphorus trichloride, the mixture is briefly heated in vacuo, cooled, and decanted. The linseed acid chlorides were also distilled in a specially modified molecular still to obtain a nearly colorless product. Presented at AOCS meeting in Cincinnati, Ohio, 1965. A laboratory of the No. Util. Res. and Dev. Div., ARS, USDA.     

Preparation of polymer-supported amino acid

Summary Insoluble polymer-supported amino acids have been synthesized by simple one-pot synthesis. Amino acids were solubilized in organic solvent by trimethylsilylation. Solubilized amino acids (L-Tyr, L-Ser, D-HPG, L-Cys) having functional groups such as OH or SH were easily attached to crosslinked polystyrene beads through benzyl ether or thioether linkage. Other amino acids without extra functional groups could be attached to the polymer through benzyl amine linkage.     

2,2-二羟甲基丙酸的合成工艺

以丙醛和甲醛为原料,经羟醛缩合及氧化两步反应,合成了2,2-二羟甲基丙酸。缩合反应在35 ℃、甲醛与丙醛物质的量比为2.4、碳酸钾用量为原料质量的6%的条件下反应10 h,氧化反应在95 ℃、过氧化氢与丙醛物质的量比为0.9的条件下反应10 h,获得了最佳反应结果,产品总收率53.5%,纯度99%。     

聚乳酸微球的制备

以L-乳酸为原料,锡粒为催化剂,实现了丙交酯的开环聚合反应,红外光谱结果表明,合成了分子量可控的聚乳酸。以二氯甲烷为溶剂,聚乙烯醇为表面活性剂,制备了聚乳酸微球,研究了聚乙烯醇浓度对聚乳酸微球的影响。结果表明,当聚乙烯醇浓度增加时,微球半径变小,但粒径分布均匀度下降,聚乙烯醇浓度为1%时,聚乳酸成球效果较好。     

Preparation of pure petroselinic acid

Petroselinic acid of 99.5–100% purity has been isolated from coriander, fennel and anise oil by acid soap crystallizations at 4C, followed by urea segregations at room temperatures.     

Factors affecting the acyltransfer activity of the lipase fromCandida parapsilosis in aqueous media

This study describes the influence of various factors on the hydrolysis and alcoholysis activities of the lipase fromCandida parapsilosis (Ashford), Langeron and Talice in aqueous media. Optimal activities were obtained at 45°C and pH 6–6.5. The influence of the nature of the substrate on the temperature activity profiles was observed. Total or partial recovery of the activities was obtained when methanol was added to the enzyme extract after thermal denaturation. A tyrosin residue appeared to be necessary for lipase function. Magnesium was a required metal cofactor. These activities were optimal in the presence of high amounts of water (water activity >0.9).     

柠檬酸硬脂酸单甘脂的合成研究

通过对柠檬酸硬脂酸单甘脂的合成研究 ,确定了以乙酸为催化剂兼溶剂 ,柠檬酸与硬脂酸单甘脂进行酯化反应的最佳工艺路线。结果表明 ,在此工艺路线下的最佳工艺条件为 :柠檬酸与硬脂酸单甘脂的摩尔比为 2∶1,乙酸用量为 10 0 % (以硬脂酸单甘脂质量计 ) ,反应温度为 12 0℃ ,酯化反应时间 3h ,真空度为 0 9MPa。该产品可作为食品乳化剂 ,在食品工业中有广泛的应用前景     

水杨酸重排法制备对羟基苯甲酸

研究了反应诸因素对水杨酸重排法制备对羟基苯甲酸产率的影响，推荐的反应条件为：反应时间７０ｍｉｎ，反应温度２４０℃，水杨酸与ＫＯＨ的物质的量比为１：１．１。按重量法计对羟基苯甲酸的收率超过３７％。     

乙醇酸和聚乙醇酸的制备与分离研究进展

乙醇酸作为一种重要的精细有机合成中间体,来源广泛。天然产物水解法,或化学法、生物法反应可得到乙醇酸粗品。现阶段我国乙醇酸的生产技术已经成熟,然而分离提纯乙醇酸的技术相对滞后。乙醇酸的分离提纯成为研究的重点和难点。本文着重总结了乙醇酸的5种分离提纯方法,主要有蒸馏和精馏法、结晶和重结晶法、甲醇酯化水解法、电渗析分离法、溶剂萃取法,其中甲醇酯化水解法和溶剂萃取法应用较多。指出了各种方法所得乙醇酸的纯度及其不足以及各种方法适用条件。此外,本文也综述了近几年合成聚乙醇酸的研究包括直接熔融聚合法、缩聚开环法、溶剂法、悬浮聚合法等,指出了各种方法的优缺点。最后,展望了乙醇酸和聚乙醇酸的应用前景,萃取法是得到高纯度乙醇酸的较好的方法,能为聚乙醇酸的合成提供优质原料,可以打破合成聚乙醇酸所用的乙交酯单体主要依赖于进口的局面。     

Preparation of long-chain fatty acid chlorides

Summary A rapid method has been found for preparing the long-chain fatty acid chlorides, which eliminates purification by distillation. It gave a quantitative yield of product containing less than 1.5% free acid. The method involves treating the free acid with phosphorus pentachloride or trichloride in an inert organic solvent and removing the excess chlorinating agent by washing the solvent phase with water. Phosphorus pentachloride and Skellysolve “F” were preferred for laboratory preparations. For commercial purposes however either chlorinating agent could be used in a variety of inert organic solvents. Infrared analysis was found to give a rapid measure of the free acid content of the prepared acid chlorides. Presented at the fall meeting, American Oil Chemists' Society, Philadelphia, Pa., Oct. 10–12, 1955. Issued as N. R. C. No. 4240.     

一种软脂酸镁清净剂的研制

以软脂酸、二氧化碳、活性-60氧化镁为原料合成润滑油类清净剂,实验结果表明,软脂酸质量为5 g,活性-60氧化镁为8 g,甲醇8 mL,70℃反应2 h,可得到碱值为282 mg(KOH)/g的软脂酸镁盐清净剂;红外谱图(IR)显示软脂酸镁清净剂含有无定型的MgCO3。     

酸性镀锌光亮剂的配制

1　前言酸性镀锌包括氯化钾镀锌、氯化钠镀锌、铵盐镀锌、硫酸盐镀锌等。其所用光亮剂均为组合型光亮剂,而且组成成分基本相同,在某些情况下,甚至可以通用。当然,硫酸盐镀锌工艺由于盐浓度较高,所以光亮剂的耐盐性要求较高。现就几种镀锌工艺光亮剂组成、含量、特点等予以介绍,并推荐相应的参考配方。2　酸性镀锌光亮剂组成成分市售酸性镀锌光亮剂的配方是保密的,各自配方虽不尽相同,但大同小异,一般均含有以下基本成分:21　主光亮剂大多是酮类、饱和或不饱和芳香醛、杂环醛。如苄叉丙酮、邻氯苯甲醛、对氯苄叉丙酮、洋茉莉醛、茴香醛等。以…     

2,6-二甲基苯硼酸的制备

以硼酸三丁酯为硼化剂,利用格氏试剂法制备2,6-二甲基苯硼酸,考察了温度和反应物配比对产率的影响。先制得格氏试剂(产率98.2%),然后在-10℃与硼酸三丁酯进行亲核取代,快速升温至20℃,经酸性水解得产品,总产率72.2%。对产品进行了核磁共振谱和质谱表征。