固定化细胞生产L－苹果酸新工艺及动力学研究

对产氨短杆菌ＭＡ－２固定化细胞在富马酸铵体系中转化生成Ｌ－苹果酸的优化工艺条件做了探讨，结果表明，富马酸铵浓度为１．８ｍｏｌ／Ｌ，ｐＨ７．０～８．０，反应温度为３７℃时，Ｌ－苹果酸得率达２００ｇ／Ｌ左右。同时，对固定化细胞的动力学进行了研究，结果为：ｒ（ｍａｘ）＝５８ｍｍｏｌ／（Ｌ·ｈ·ｇ固定化湿细胞）），Ｋｍ＝６．２５×１Ｏ￣（－２）ｍｏｌ／Ｌ，Ｐ＿ｍ＝１．５６ｍｏｌ／Ｌ     

固定化黄色短杆菌生产L－苹果酸新工艺及动力学研究

研究了固定化黄色短杆菌ＭＡ－３在富马酸盐体系中转化生成Ｌ－苹果酸的新工艺，研究结果表明当富马酸铵盐浓度为１．８ｍｏｌ／Ｌ，体系ｐＨ为７．０～８．０，反应温度为３７℃时，Ｌ－苹果酸的得率达２１６ｇ／Ｌ。对固定化黄色短杆菌的动力学研究结果为Ｖｍａｘ＝７６ｍｍｏｌ／［Ｌ·ｈ·ｇ（固定化湿细胞）］，Ｋｍ＝４．７６×１０－２ｍｏｌ／Ｌ，Ｃｐｍ＝１．６９ｍｏｌ／Ｌ。     

L—苹果酸中富马酸含量控制的工艺研究

本文对应用固定化细胞酶生产Ｌ－苹果酸工艺过程中富马酸含量的控制进行工艺研究，将研究结果应用于工业化生产，Ｌ－苹果酸中富马酸含量能有效地控制在０．３％以下，本研究对工业化生产Ｌ－苹果酸具有一定的指导作用。     

固定化细胞技术在苹果酸生产中的应用及改进

介绍了固定化细胞技术生产L－苹果酸的原理,对菌泥分级,包埋活化等工艺条件进行了优化,固定化细胞的有效活力期和苹果酸转化率均有所提高,年降低消耗26万元。     

苹果酸生产中残留富马酸转成天门冬氨酸的研究

建立了固定化细胞分离Ｌ－苹果酸生产中残留富马酸并将其转化成Ｌ－天门冬氨酸的新方法。对生成Ｌ－天门冬氨酸的工艺条件进行优化，结果表明，当Ｌ－苹果酸反应液ｐＨ调至８～９，Ｌ－天门冬氨酸添加量为６～８ｇ／Ｌ，碳酸铵加量为１５～２０ｇ／Ｌ，Ｍｇ￣（２＋）、Ｍｎ￣（２＋）、Ｃａ￣（２＋）等二价阳离子加量为１ｍｍｏｌ／Ｌ时，固定化细胞可将Ｌ－苹果酸反应液中残留的２０％左右的富马酸几乎全部转化成Ｌ－天门冬氨酸，且Ｌ－苹果酸含量的损失小于５％。     

L—苹果酸生产中转晶工序最佳工艺参数的确定

Ｌ＿苹果酸生产中转晶工序最佳工艺参数的确定顾作顺（唐山滦化集团公司唐山市０６３０００）１前言Ｌ－苹果酸是体内循环的成员之一，也是氨基酸输液的组成之一，已被国内外越来越多的行业所应用。工业化生产Ｌ－苹果酸的最佳途径是用延胡索酸酶法转化延胡索酸（俗名富马...     

固定化细胞技术发酵产氢的应用研究

微生物发酵产氢的固定化细胞技术与其非固定化细胞技术相比,前者具有很大的优越性,能显著提高发酵系统的产氢量。对微生物发酵产氢固定化细胞的制备方法及其应用载体进行了介绍,分析了国内外固定化细胞技术在厌氧产氢中的最新进展,指出了固定化细胞技术发酵产氢存在的问题,并对其发展进行了探讨。     

诱变温特曲霉转富马酸为L-苹果酸的研究

采用经^60Co诱变的温特曲霉转富马酸为L-苹果酸,对影响转化结果的主要因素进行了探讨。试验结果表明摇瓶发酵的较佳工艺为：富马酸初始浓度11％～12％（质量分数）,发酵时间96～106h,pH6．5～7．5,温度30℃。在此适宜条件下,富马酸平均转化率83．51％,平均产L-苹果酸11％。菌种经诱变选育后使富马酸的转化率平均提高100k,种子培养时间由3d缩短为1d。     

微生物短杆菌(Brevibacterium sp.)选择性降解制备(R)-扁桃酸

以外消旋扁桃酸为底物,筛选出一株短杆菌Brevibacterium sp. CCSYU 10011,该菌能转化外消旋扁桃酸为(R)-扁桃酸. 用全细胞转化法研究发现,其转化过程是不对称降解过程,即选择性降解了(S)-扁桃酸,进而获得(R)-扁桃酸. 考察了温度、pH、底物浓度及细胞量等因素对(S)-扁桃酸降解的影响,转化结束后,收率为48.7%,对映体过量值(e.e.)可达99%.     

放线菌酮对米根霉积累L-苹果酸代谢途径的调控作用

实验考察了富马酸酶活抑制剂放线菌酮对米根霉发酵产L-苹果酸和富马酸的影响. 结果表明,发酵16 h加入浓度15 mg/L的放线菌酮使米根霉富马酸酶胞质同功酶比活力峰值降低48.7%,而苹果酸脱氢酶胞质同功酶活力却未有明显改变,生成的富马酸比对照样减少37.1%,而L-苹果酸积累量提高54.6%,达到21.7 g/L. 表明通过对米根霉富马酸酶胞质同功酶的抑制作用能减弱米根霉积累富马酸代谢途径中由L-苹果酸向富马酸的转化,从而促进米根霉积累L-苹果酸.     

固定化D-氨基酸氧化酶转化头孢菌素C为戊二酰基-7-氨基头孢霉烷酸

部分纯化的变异三角酵母D-氨基酸氧化酶(DAO)在碱性条件下变性过氧化氢酶,再与大孔聚甲基丙烯酸缩水甘油酯高聚物共价交联。与游离酶相比,固定化酶的最适反应温度升高,最适pH范围变宽,对温度和pH的稳定性都有明显的提高。固定化DAO在搅拌反应器中催化头孢霉素C(CPC)转化为戊二酰基-7-氨基头孢霉烷酸(Gl-7-ACA)。以0.03g/mL的CPC为底物,在温度25℃、pH7.2条件下,产物的得率>93%,副产物得率<5%。经过110批反应后,固定化酶保持64%的初始活力。     

碱性离子交换树脂分离L-苹果酸的研究

考察了 7种阴离子交换树脂对L 苹果酸及杂质氯离子的吸附行为。通过静态交换实验 ,初步选择了实验所用树脂 ,同时考察了温度对吸附过程的影响并确定实验在室温下进行 ,在此基础上 ,考察了所选树脂对L 苹果酸、氯离子的动态吸附性能及选择性能 ,选择D30 1为提纯L 苹果酸的树脂 ,对模拟生产中混合料液的质量浓度的L 苹果酸溶液进行分离 ,在 pH =3 4,流速为 2mL/min左右时 ,经处理后的料液中检测不到氯离子     

Repeated-Batch and Continuous Production of L-Lactic Acid by Rhizopus oryzae Immobilized in Calcium Alginat Beads: Reactor Performance and Kinetic Model

Repeated-batch and continuous production of L-lactic acid by immobilized Rhizopusoryzae with calcium alginate entrapment method in a three-phase fluidized-bed bioreactor was stud-ied.The operation conditions were optimized.The productivity based on total reactor volume wasabout 3 times higher than that with free cells in a traditional stirred tank bioreactor.A mathemat-ical model was proposed and the model predictions were in good agreement with the experimentaldat.     

L-乳酸生产中硫酸对脱除糖的作用研究

研究了乳酸精制过程中硫酸浓度、酸解温度对脱除总糖的作用,得出了酸解最佳工艺条件为:硫酸浓度98%,酸解温度为95℃,此时,残糖脱除率为96.2%。     

Gamma-Aminobutyric Acid Production Using Immobilized Glutamate Decarboxylase Followed by Downstream Processing with Cation Exchange Chromatography

We have developed a gamma-aminobutyric acid (GABA) production technique using his-tag mediated immobilization of Escherichia coli-derived glutamate decarboxylase (GAD), an enzyme that catalyzes the conversion of glutamate to GABA. The GAD was obtained at 1.43 g/L from GAD-overexpressed E. coli fermentation and consisted of 59.7% monomer, 29.2% dimer and 2.3% tetramer with a 97.6% soluble form of the total GAD. The harvested GAD was immobilized to metal affinity gel with an immobilization yield of 92%. Based on an investigation of specific enzyme activity and reaction characteristics, glutamic acid (GA) was chosen over monosodium glutamate (MSG) as a substrate for immobilized GAD, resulting in conversion of 2.17 M GABA in a 1 L reactor within 100 min. The immobilized enzymes retained 58.1% of their initial activities after ten consecutive uses. By using cation exchange chromatography followed by enzymatic conversion, GABA was separated from the residual substrate and leached GAD. As a consequence, the glutamic acid was mostly removed with no detectable GAD, while 91.2% of GABA was yielded in the purification step.     

Revisiting the Enzymatic Epoxidation of Vegetable Oils by Perfatty Acid: Perbutyric Acid Effect on the Oil with Low Acid Value

Enzymatic epoxidation of vegetable oils in the presence of free fatty acids has been well studied in recent years, by mainly using long chain fatty acids (e.g., stearic acid) as the active oxygen carrier. However, for the previous enzymatic processes, the acid value (AV) of final epoxidized oils using long chain fatty acids is high, and the free fatty acid is not easily removed in the post treatment with water. Aiming at developing a more sustainable process, enzymatic epoxidation of sunflower oil was revisited using different free fatty acids catalyzed by Novozym 435 (lipase B from Candida antarctica, provided by Novozymes, Bagsvaerd, Denmark). When long chain stearic acid was introduced into the epoxidation in toluene solvent, the epoxy oxygen group content (EOC) of 6.41 ± 0.19 % was obtained. Due to the poor water solubility of stearic acid, the AV of the final epoxidized oil product was very high (53.40 ± 1.34) after it was washed with water. Alternatively, current study shows that the epoxidation process using short chain butyric acid produced the final epoxidized oil with lower AV of 2.57 ± 0.11. When the enzymatic epoxidation of sunflower oil was optimized in the presence of butyric acid and Novozym 435, EOC of 6.84 ± 0.21 % was obtained, reaching an oxriane conversion of 96.4 ± 3.0 %. Therefore, introducing short chain butyric acid as an active oxygen carrier will provide an alternative to the present enzymatic epoxidation process and produce the desired epoxidized oil products with much lower AV only after simple water‐treatments, which will make the enzymatic epoxidation more attractive.     

酶法合成三氮唑核苷新工艺的研究

本文报道经过低温、培养基条件诱导选育所得的乙酰短杆菌ＴＱ９５２菌株，在８Ｌ和１００Ｌ发酵罐培养以及该菌体在酶反应过程的优化试验。以１００ｍｍｏｌ／Ｌ鸟苷和三氮唑甲酰胺为底物，利用ＴＱ９５２菌体的核苷磷酸化酶催化反应，其三氮唑核苷平均转化率８６％，最高９５％。