符合GMP的固液离心分离技术——德国海因克尔（HEINKEL）翻袋式离心机

离心分离技术是化工、生物及制药行业不可或缺的重要手段。从啤酒和果酒的澄清．酵母发酵醪浓缩．谷氨酸结晶的分离，至各种发酵液的菌体分离和疫苗．抗生素．干扰素的生产都大量使用各种类型的离心分离设备。本文着重介绍了德国海因克尔(HEINKEL)翻袋式离心机。     

发酵法生产1，3-丙二醇的下游加工之滤除菌体方法的研究

利用钙离子对多糖类物质、果胶物质的吸附作用；氢氧根离子对微生物细胞的破坏作用以及氢氧化钙所带电荷去中和发酵液溶胶所带的负电荷而使菌体聚集而絮凝。对利用克雷伯氏肺炎杆菌以甘油、葡萄糖为底物发酵生产1，3-丙二醇的下游加工过程中的絮凝过滤进行了初步研究，提高了1，3-丙二醇的收率，降低了其下游加工的成本。     

膜过滤技术在维生素B12生产中的应用

采用聚偏氟乙烯(PVDF)中空纤维微滤膜对维生素B12发酵液进行了除菌研究.发酵液经过微滤膜过滤后,菌体完全去除(去除率100%),远高于离心机除茵效果(去除率70%),滤液的澄清度及质量得到提高.另外,对污染膜的清洗研究表明,一般情况下0.1%的NaOH溶液清洗效果理想,当污染严重时,超声波振荡清洗效果最有效.     

中空纤维膜在阿卡波糖复滤中的应用

阿卡波糖Actinoplanes utahensis在临床上被用来治疗Ⅱ型糖尿病。阿卡波糖是由游动放线菌经发酵产生,发酵液经板框压滤得到滤液。但滤液中往往含有菌丝残渣、蛋白等,不但影响收率,严重时会使树脂失效,影响生产进度。本试验主要利用中空纤维膜物理拦截法去除滤液中的残留菌丝以及蛋白的效果进行研究,试验证明截留分子量在5-10万的中空纤维膜适用于阿卡波糖复滤工艺。     

两步超滤膜法分离提取发酵液中聚苹果酸

采用两步超滤法对出芽短梗霉发酵产生的聚苹果酸进行分离与提取.发酵液经离心去除菌体后,先采用截留相对分子质量为30 000的超滤膜除去多糖及大分子杂质,接着采用截留相对分子质量为1 000的超滤膜对料液进行浓缩并除去小分子杂质,浓缩液经有机溶剂沉淀和冷冻干燥获得聚苹果酸.采取单因素实验法优化了超滤条件,结果表明:离心除菌后的发酵上清液稀释4倍,跨膜压差0.075 MPa,控制料液pH--6、温度35℃,使用相对分子质量30 000超滤膜稀释超滤1次,分子量1 000超滤膜浓缩4倍后,经甲醇沉淀和冷冻干燥,PMLA的纯度达到82.3％,PMLA的提取收率为57.56％.     

1,3-丙二醇发酵液絮凝技术的研究

1,3-丙二醇(1,3-Propanediol,以下简称1,3-PDO)可以与对苯二甲酸聚合成对苯二甲酸丙二醇酯(PTT),PTT是由壳牌公司首先研制出的可应用纺织纤维领域的新一代聚酯,具有广泛的应用前景。目前,1,3-丙二醇的生产方法主要有化学合成法和微生物发酵法两种。其中化学合成法已经用于工业生产,而微生物发酵法因其选择性高、操作条件温和、原料是可再生的农产品——淀粉或植物油料等优点,是近些年来国内外研究的重点。1,3-丙二醇发酵液在后提取过程中的第一个步骤是菌体去除,目前工业上主要采用离心分离和直接过滤。由于离心分离投资过大,直接过滤消耗人力、物力过大,所以投资小、效果好的絮凝预处理方法也正在一些菌体分离中得到应用。     

重组人IL-6/IL-2融合蛋白的高密度发酵和纯化

克隆的IL-6/IL-2融合蛋白编码基因插入pBV220载体,转化BL21(DE3)菌株中表达。发酵过程中,30℃扩增生长6小时,42℃诱导培养4小时,控制溶解氧在30％～50％。发酵液中最终菌体密度(OD600)达29.17(相当于每升发酵液含55克湿菌体),表达的融合蛋白呈包涵体形式。表达蛋白占菌体总蛋白的30％左右。菌体经过超声破碎后反复洗涤包涵体,融合蛋白纯度达到70％,进一步用离子交换层析和凝胶过滤层析纯化使其纯度达95％以上。IL-6/2融合蛋白中的IL-6和IL-2活性分别为1×107和2×105 U/mg。重组人IL-6,/IL-2融合蛋白在大肠杆菌中达到了中试水平的高表达。     

用超过滤,反渗透技术处理古龙酸发酵液的研究

本文对药厂提供的酸性强、高混浊的古龙酸发酵液首先采用超过滤脱除发酵液中的蛋白、菌体及其他杂质,然后经过反渗透浓缩,所得产品古龙酸含量86%～89%,溶点约160℃,完全符合药厂产品标准。采用超过滤与反渗透技术后,与原工艺比较,可大大节省能源。本文还对适应古龙酸液浓缩、分离用的膜种类进行了探讨。     

电凝聚气浮对南湖水净化的试验研究(英文)

通过改变便携式供水设备电凝聚气浮部分的电流密度、通电时间、静沉时间、pH值等因数,对武汉南湖水中的浊度、化学需氧量的去除效果进行试验研究,得出该设备电凝聚气浮部分能对水中浊度有效去除,同时对化学需氧量具有很强的降解作用,并由此得到电凝聚气浮部分的最佳操作条件。     

电凝聚对微污染水净化的试验研究

通过改变电流密度、通电时间、沉淀时间等因素,采用电凝聚法对微污染水中的细茵、浊度、CODMn的去除进行了试验研究.得出了电凝聚通过电解氧化、凝聚和气浮联合作用,对微污染水中的浊度、细菌能有效地去除,同时对CODMn具有很强的降解作用.     

Formation of pyroglutamic acid from N-terminal glutamic acid in immunoglobulin gamma antibodies

The status of the N-terminus of proteins is important for amino acid sequencing by Edman degradation, protein identification by shotgun and top-down techniques, and to uncover biological functions, which may be associated with modifications. In this study, we investigated the pyroglutamic acid formation from N-terminal glutamic acid residues in recombinant monoclonal antibodies. Almost half the antibodies reported in the literature contain a glutamic acid residue at the N-terminus of the light or the heavy chain. Our reversed-phase high-performance liquid chromatography-mass spectrometry method could separate the pyroglutamic acid-containing light chains from the native light chains of reduced and alkylated recombinant monoclonal antibodies. Tryptic peptide mapping and tandem mass spectrometry of the reduced and alkylated proteins was used for the identification of the pyroglutamic acid. We identified the formation of pyroglutamic acid from N-terminal glutamic acid in the heavy chains and light chains of several antibodies, indicating that this nonenzymatic reaction does occur very commonly and can be detected after a few weeks of incubation at 37 and 45 degrees C. The rate of this reaction was measured in several aqueous buffers with different pH values, showing minimal formation of pyroglutamic acid at pH 6.2 and increased formation of pyroglutamic acid at pH 4 and pH 8. The half-life of the N-terminal glutamic acid was approximately 9 months in a pH 4.1 buffer at 45 degrees C. To our knowledge, we showed for the first time that glutamic acid residues located at the N-terminus of proteins undergo pyroglutamic acid formation in vitro.     

聚偏氯乙烯超滤膜的辐照接枝改性研究

聚偏氟乙烯超滤膜经Ｃｏ－６０辐照，接枝乙烯基单体，再经磺化，成为磺化聚氟乙烯超滤膜。研究了辐照剂量、接枝时间对接枝率的影响和磺化反应的条件等。试验表明，改性后膜的亲水性和抗污染性增强。此外，还讨论了膜改性的机理。     

PVA修饰的溶胶凝胶法制备γ氧化铝超滤膜

用硝酸铝水解的溶胶凝胶法,在微滤αＡｌ２Ｏ３以撑体上制备了超滤γ－Ａｌ２Ｏ３膜,考究了聚乙烯醇对勃姆石胶体稳定性和膜制备的影响。用扫描电镜、气体和液体渗透和载留分子量等实验方法,对所制备的不对称膜进行了表征。     

Polymeric receptors for the recognition of folic acid and related compounds via substructure imprinting

A range of 2-acrylamidopyridines, showing subtle differences in solution binding toward carboxylic acids, has been investigated as functional monomers in molecular imprinting. Imprinting of N-Z-L-glutamic acid with one such monomer is shown to be effective in the creation of a molecularly imprinted polymer (MIP) with recognition properties for its template and also for larger molecules containing glutamic acid residues. In comparison to a MIP prepared via a more "traditional" approach, the new polymeric receptors exhibit reduced nonspecific binding. The new receptors are compared with previously reported urea-based receptors targeting the glutamic acid residue and receptors targeting the pteridine substructure of folic acid.     

Effects of amino acids on microcystin production of the Microcystis aeruginosa

A Microcystis aeruginosa which produced high content of microcystin-LR (MC-LR) but no microcystin-RR (MC-RR) was isolated from Dianchi Lake in China. In the molecular structure of MC-LR, glutamic acid, aspartic acid, leucine, alanine and arginine are the constitutional components which are abundant in natural water. In this paper, effects of six amino acids at their natural concentrations on the growth of the M. aeruginosa and the microcystin (MC) production were studied in batch culture. M. aeruginosa could assimilate alanine, leucine and arginine as sole nitrogen sources for growth and MC production. However, glutamic acid, aspartic acid and lysine could not be assimilated quickly, although they could pass the cell membrane and enter into the cell rapidly. Our experiment demonstrated that the possible reason of such phenomenon was that different amino acids had different effects on the process of metabolism through the free dissolved amino acids within the cells.     

Intramolecular synergistic effect of glutamic acid, cysteine and glycine against copper corrosion in hydrochloric acid solution

The corrosion protection of copper by glutamic acid, cysteine, glycine and their derivative (glutathione) in 0.5 M hydrochloric acid solution has been studied by the electrochemical impedance spectroscopy and cyclic voltammetry. The inhibition efficiency of the organic inhibitors on copper corrosion increases in the order: glutathione > cysteine > cysteine + glutamic acid + glycine > glutamic acid > glycine. Maximum inhibition efficiency for cysteine reaches about 92.9% at 15 mM concentration level. The glutathione can give 96.4% inhibition efficiency at a concentration of 10 mM. The molecular structure parameters were obtained by PM3 (Parametric Method 3) semi-empirical calculation. The intramolecular synergistic effect of glutamic acid, cysteine and glycine moieties in glutathione is attributed to the lower energy of the lowest unoccupied molecular orbital (E_LUMO) level and to the excess hetero-atom adsorption centers and the bigger coverage on the copper surface.     

Preparation and biological evaluation of hydroxyapatite-coated nickel-free high-nitrogen stainless steel

Calcium phosphate was formed on nickel-free high-nitrogen stainless steel (HNS) by chemical solution deposition. The calcium phosphate deposition was enhanced by glutamic acid covalently immobilized on the surface of HNS with trisuccinimidyl citrate as a linker. X-ray diffraction patterns and Fourier transform infrared spectra showed that the material deposited on glutamic acid-immobilized HNS within 24 h was low-crystallinity calcium-deficient carbonate-containing hydroxyapatite (HAp). The biological activity of the resulting HAp-coated HNS was investigated by using a human osteoblast-like MG-63 cell culture. The HAp-coated HNS stimulated the alkaline-phosphate activity of the MG-63 culture after 7 days. Therefore, HAp-coated HNS is suitable for orthopedic devices and soft tissue adhesion materials.     

Preparation and biological evaluation of hydroxyapatite-coated nickel-free high-nitrogen stainless steel

Abstract

Calcium phosphate was formed on nickel-free high-nitrogen stainless steel (HNS) by chemical solution deposition. The calcium phosphate deposition was enhanced by glutamic acid covalently immobilized on the surface of HNS with trisuccinimidyl citrate as a linker. X-ray diffraction patterns and Fourier transform infrared spectra showed that the material deposited on glutamic acid-immobilized HNS within 24 h was low-crystallinity calcium-deficient carbonate-containing hydroxyapatite (HAp). The biological activity of the resulting HAp-coated HNS was investigated by using a human osteoblast-like MG-63 cell culture. The HAp-coated HNS stimulated the alkaline-phosphate activity of the MG-63 culture after 7 days. Therefore, HAp-coated HNS is suitable for orthopedic devices and soft tissue adhesion materials.     

壳聚糖超滤膜的研究

以壳聚糖为原料，2％乙酸为溶剂，选择适当的膜液组成和制备条件，可以制得截留分子量为67000的超滤膜．该膜对0．1％牛血清蛋白的截留率可达90％以上．研究了铸膜液组成和若干因素对膜性能的影响．