丙酮酸的发酵代谢机理研究

近年来,丙酮酸广泛用于医药、化工、保健品等行业中,应用领域不断扩大,世界上需求量不断增长。发酵法生产丙酮酸由于具有成本低廉、产品纯度高、反应条件温和、对环境友好而得到发展。论述了代谢分析在丙酮酸发酵中的应用,包括乙酸渗漏菌株的筛选、能量代谢调控等,同时指出了今后的研究方向。     

代谢分析用于丙酮酸发酵的研究进展

丙酮酸是重要的有机合成中间体,广泛应用于医药、化妆品、化学生产等工业中。但目前以发酵法生产丙酮酸的产量不高。近年来,有很多研究者通过代谢控制手段来提高乳酸、缬氨酸、丙酮酸等有机酸的产量。综述了代谢分析在丙酮酸发酵工艺优化中的研究应用进展。     

我国丙酮酸及系列产品合成工艺10 a进展

综述了丙酮酸及系列产品近10 a来合成工艺的发展状况。介绍了目前国内生产丙酮酸的各种合成工艺方法,包括酒石酸法、乳酸氧化法、直接发酵法和酶催化法,阐述了它们的合成反应原理、工艺参数、产率等,评价了这些方法的利弊与发展前景。     

络合萃取分离乳酸与丙酮酸技术研究

丙酮酸是一种重要的有机化工中间体,用途广泛,市场风靡全球。生产方法有化学合成法、酶转化法和生物发酵法。介绍了一种运用生物催化转化与化学催化转化生产方式,技术的关键之一在于乳酸与丙酮酸的分离,本研究采用萃取的方式实现分离,分离成本大幅降低。     

生物转化法生产L-苯基乙酰基甲醇的研究进展

综述了L-苯基乙酰基甲醇(L-PAC)生物转化机理、菌种选育、转化体系选择、生产过程优化、下游处理等方面的研究进展. 目前,主要采用具有高活性的丙酮酸脱羧酶的Saccharomyces属和Candida属菌株,以苯甲醛和丙酮酸为底物转化生产L-PAC. 生成副产物和底物苯甲醛的毒性是限制产量提高的主要因素. 通过菌株筛选和选育可减少副产物生成并提高菌株耐受性. 通过控制及优化转化过程参数、分批补加底物、采取固定化细胞或固定化酶措施及建立适宜的两相转化体系,能有效提高产量.     

番茄红素的理化性质及其生产方法的研究进展

综述了近年来国内外番茄红素的生产方法和研究现状,展望了番茄红素生产的发展方向,认为通过高产菌株的发酵法生产番茄红素将是今后的研究热点。     

基于关键酶表达的发酵调控与分子改造策略对E.coli产丁二酸的影响

考察E.coli JM001及其重组菌株E.coli JM002生物发酵生产丁二酸的性能。E.coli JM001在两阶段发酵产丁二酸过程中通过在有氧培养阶段添加乙酸钠,即可提高丁二酸的生产能力,厌氧阶段的丁二酸收率可达84%,但会有较多的副产物乙酸和丙酮酸积累。以E.coli JM001为出发菌株,敲除其磷酸烯醇式丙酮酸羧化酶(PPC)并导入来源于枯草芽孢杆菌的磷酸烯醇式丙酮酸羧化激酶(PCK)基因,构建了重组菌株E.coli JM002,该重组菌株在两阶段发酵的有氧培养过程中不需添加乙酸钠,转厌氧后菌株也具有转化葡萄糖合成丁二酸的能力,丁二酸收率可达86%,副产物积累很少。     

离子交换法分离提取发酵液中L-亮氨酸

L-亮氨酸是人与动物自身不能合成而必须依赖外源供给的八大必需氨基酸之一，在医药、食品、饲料等方面具有重要应用价值。目前L-亮氨酸的生产方法主要有水解法、化学合成法、添加前体发酵法、薇生物直接发酵法等，但以薇生物发酵法生产L-亮氨酸最具有发展前途。     

苯丙氨酸制备技术的进展

阐述了开发苯丙氨酸的重要性，概述了当前采用的蛋白质水解法、发酵法、酶法、化学合成法等生产方法及其最新技术进展。提出了引进优良菌株、在我国尽快将酶转化法用于苯丙氨酸生产，加快化学合成法的开发研究等建议。     

生酮基古龙酸菌及其分子生物学研究进展

生酮基古龙酸菌是两步发酵法生产维生素C（VC）过程中的关键菌株,其能够充分转化L-山梨糖生成2-KGA,KV菌的转化代谢机制和氧化还原酶系一直是VC生产中的研究热点。KV菌的全基因组序列已经测定完成,基因注释工作正在积极推进。综述了VC生产研究进展、两步发酵法及KV菌发子生物学研究进展。指出随着研究工作的深入,越来越多的在转化L-山梨糖生成2-KGA过程中起关键作用的醇醛脱氢酶被发现。KV菌分子生物学方面的进展为革新VC生产工艺,大幅度降低生产成本,为我国的VC产业在竞争中获胜奠定了基础。     

丙酮酸高产菌诱变选育及发酵工艺优化的初步研究

以光滑球拟酵母(Torulopsis glabrata)HB20为出发菌,经过UV和DES复合诱变选育出一株丙酮酸高产菌HB304.鉴定其为维生素营养缺陷型,摇瓶发酵产酸量比原菌增加了31.2%;优化培养基后其摇瓶发酵产酸量比原菌增加了41.9%.     

Selective electroreduction of pyruvic acid on lead electrode in acid medium

This work reports the electrochemical reduction of pyruvic acid, which contains a carbonyl group more reducible than its carboxylic entity. The electrode potential and the concentration of the starting substrate seemed to be the factors that control the electrochemical production of the competitive reaction products. In fact, lactic acid was mainly obtained on a lead electrode in sulfuric acid for low concentrations of pyruvic acid while 2,3-dimethyl tartaric acid was selectively formed by electrohydrodimerization of a high amount of pyruvic acid. During the cathodic reduction of pyruvic acid in sulfuric acid solution, the effects of electrode potential and pyruvic acid concentration on the selectivity towards the formation of lactic acid were systematically studied.     

抗癌药物比卡鲁胺

介绍过期专利抗癌药物比卡鲁胺的基本性能和作用。并概述了分别以溴丙酮、2-甲基丙烯酰氯、2-甲基丙烯酸甲酯、2,3-二羟基-2-甲基丙酸以及丙酮酸或丙酮酸酯为起始原料合成比卡鲁胺的方法。其中以丙酮酸或丙酮酸酯为原料的合成方法为最佳。     

A simple 1H N.m.r. Method for the quantitation of O-acetate ester and pyruvic acid acetal content of polymeric xanthan gum and related polysaccharides

Traditional methods for the quantitation of O-acetate ester and pyruvic acid acetal in xanthan gums require hydrolysis procedures followed by determination of acetic acid and pyruvic acid separately either by colorimetric, enzymic or chromatographic assays. Some of these assays are time-consuming and involve many solvent extractions, and during the course of these procedures the xanthan sample is destroyed by hydrolysis. The methyl protons of both O-acetate ester and pyruvic acid acetal can be detected by ¹H n.m.r. spectroscopy, and this paper describes a method for the quantitative determination of these groups on intact polymeric xanthan using an internal integration standard dissolved within the sample. The method is non-destructive, can be easily performed on a 60MHz spectrometer equipped with Fourier Transformation and variable temperature control, and simultaneously quantitates both O-acetate ester and pyruvic acid acetal with improved accuracy.     

Recovery of pyruvic acid with weakly basic polymeric sorbents

BACKGROUND: Carboxylic acids are among the most important substances that can be manufactured from biomass. However, the recovery of carboxylic acids from fermentation broths presents a challenging separation problem. To avoid the production of waste salts and net consumption of chemicals in the calcium carboxylate salt process, the use of reversible chemical complexation with polymeric sorbents and extractants is attractive for carboxylic acid recovery. Pyruvic acid is widely used in the manufacture of medicines, pesticides and foodstuffs and can be produced by fermentation. Since the acidity of pyruvic acid (pK_a = 2.49) is stronger than that of normal carboxylic acids, and as few reports on the recovery of pyruvic acid are available, the sorption of pyruvic acid from aqueous solution on two types of weakly basic polymeric sorbent, tertiary amine D301R and primary amine D392, was investigated over a wide pH range and at various salt (MgSO₄) concentrations. RESULTS: Overloading adsorption of pyruvic acid on both weakly basic polymeric sorbents occurred, with the overloading of D392 being greater than that of D301R. The adsorption of pyruvic acid on both sorbents was greatly affected by the solution pH and the salt concentration in the aqueous phase. An overloading model was able to predict the experimental uptake data very well. CONCLUSION: Solution pH is one of the most important operating conditions, and both polymeric sorbents D392 and D301R can be used to recover pyruvic acid from dilute aqueous solution with high efficiency at a solution pH around 2. The uptake by D392 is greater than that by D301R owing to steric hindrance of the tertiary amine. Copyright © 2008 Society of Chemical Industry     

色氨酸酶重组基因表达及其酶法合成L-色氨酸

为实现色氨酸酶高效、低成本催化合成L-色氨酸,利用p ET30a为载体在宿主细胞E.coli BL21(DE3)中重组表达了产气肠杆菌(Enterobacter aerogenes)来源的色氨酸酶,以丙酮酸、吲哚和氨为底物,探究其酶学性质,考察了反应温度、起始p H、底物摩尔比对酶促反应的影响,并利用丙酮酸发酵液为底物酶法合成L-色氨酸。结果表明,色氨酸酶重组表达成功,色氨酸酶最佳反应条件为:温度35℃,起始p H=9.0,底物摩尔比n(吲哚)∶n(丙酮酸)=0.6∶1,底物丙酮酸浓度为0.17 mol/L。利用重组色氨酸酶全细胞催化100 m L浓度为0.57 mol/L丙酮酸发酵液,流加浓度为4.27 mol/L吲哚酒精溶液6.5 m L,反应28 h后,L-色氨酸浓度达0.25 mol/L,吲哚摩尔转化率达91.8%。     

Electrosynthesis of 2,3-dimethyltartaric acid from pyruvic acid in acid medium

This study reports the electrohydrodimerization of pyruvic acid to 2,3-dimethyltartaric acid in sulphuric acid medium (0.5 M H₂SO₄) on a lead cathode. The main products detected were lactic acid and 2,3-dimethyltartaric acid. The selectivity towards the formation of 2,3-dimethyltartaric acid was studied vs. pyruvic acid concentration in sulphuric acid solution, at −1.1 V vs. MSE. The best selectivity of 2,3-dimethyltartaric acid reached 69% for an initial concentration of 1.7 M pyruvic acid. The yield of pyruvic acid was 84%.     

丙酮酸的合成研究进展

丙酮酸作为一种重要的有机化工产品，日益广泛地应用于医药、农药、日化和食品等行业。本文从化学合成法和生物技术法两个方面，详细介绍了丙酮酸合成现状及其研究进展，并对丙酮酸的发展前景进行了展望。通过对上述两种方法优缺点的比较，指出生物技术法具有原料成本低、产物纯度高、反应条件温和等优点，具有良好的发展前景。