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安丝菌素是从珍贵橙色束丝放线菌的发酵液中分离出来的苯安莎类抗生素,具有显著的抗肿瘤活性。常采用乙酸乙酯对发酵液进行分离萃取,然而其发酵液成分复杂,除菌丝体外还含有许多杂蛋白质及易溶于有机溶剂的色素,这对后续提取和精制有很大的影响,影响产品质量和回收率。本文通过对AP-3发酵液进行预处理,将AP-3发酵液调整pH至3后,用10g/L硅藻土辅助抽滤;收集滤液,添加20g/L活性炭于60℃吸附2h,然后用洗脱液乙酸乙酯对活性炭进行脱附处理,2h后达到动态洗脱平衡,对洗脱液采用中性氧化铝柱层析,以乙酸乙酯和石油醚作为洗脱剂进行梯度洗脱,最终获得AP-3纯度86.15%,经重结晶后得到AP-3纯品,经过HPLC检测AP-3纯度达95%。 相似文献
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为了探索珍贵橙色束丝放线菌(Actinosynnema pretiosum)合成安丝菌素P-3(AP-3)的固体发酵培养条件的最佳工艺,利用农副产品(玉米淀粉、玉米粉、棉籽饼粉、豆粕、豆饼粉、菜籽饼粉、麦麸、米糠)作为固料,采用单因素实验和正交实验对固体发酵培养基组成及培养条件进行摸索。得到合成AP-3固体发酵的最佳培养基组分为:玉米淀粉、豆粕及棉籽饼粉的质量配比为1:1:1,红糖4%,玉米浆干粉2%,CaCl2 1%。最佳固体发酵工艺条件为:初始pH为7.5,培养温度28℃,固液比(质量比)为1:0.8,装量25g(250mL锥形瓶),接种量150mL/kg,培养时间为7天,最优条件下AP-3的产量为(26.86±1.87)mg/kg(每千克培养基)。本研究为发酵合成安丝菌素提供了新的方法与思路。 相似文献
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苯乳酸是一种高值有机酸和新型的天然防腐剂,可由乳酸菌等多种微生物代谢产生。苯乳酸有着较为宽广的抑菌谱,对大多数革兰氏阳性、阴性菌和真菌都有明显的抑菌作用,不仅作为天然抑菌剂可替代化学合成的防腐剂,而且可经聚合反应合成聚苯乳酸新型高分子材料,作为聚乳酸高分子的替代物。因此,苯乳酸在化工、制药、生物、材料和食品等领域有广阔的应用前景。本文从苯乳酸抑菌特性、微生物菌株、转化合成、代谢途径及下游分离纯化等方面,简述了其生物转化合成和分离的研究现状。微生物菌株是苯乳酸合成的关键,基因工程菌的转化能力虽然高效,但构建工程菌较复杂;从自然环境中筛选安全优良的菌株,可以简化转化合成过程,提高转化率和料液中苯乳酸的浓度;苯乳酸的分离纯化还处于实验室的规模,有待进一步探索以达到工业化的要求。 相似文献
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[目的]对球毛壳菌素A的提取分离和发酵工艺优化进行了研究,并采用HPLC进行定量分析,为建立产量高、成本低、无污染的规模化球毛壳菌发酵生产工艺打下基础.[结果]经均匀设计法优化出培养基配方中碳源和氮源最优组合为蔗糖17 g/L,淀粉6 g/L,蛋白胨0.5 g/L,最佳发酵时间为13d.采用乙酸乙酯作提取剂,浸泡时间为3d.分离纯化采用乙酸乙酯-石油醚(体积比1:3)为洗脱剂,展开剂采用乙酸乙酯-石油醚-甲酸(体积比37:63:1)为最佳.[结论]通过对培养基配方的优化,球毛壳菌发酵产生球毛壳菌素A的发酵量可达到0.17g/L,比目前已报道的文献值高13.3%. 相似文献
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《化学工程》2017,(11)
结晶过程是影响晶体质量的关键步骤。本实验采用溶析结晶工艺对泰乐菌素结晶过程进行研究,以收率、粒度和粒度分布为目标,考察了水和丙酮质量比、晶种加入量(质量分数)、结晶温度、初始浓度、搅拌转速、陈化时间和流加速率等操作因素对结晶过程的影响。结果表明:所有参数在考察的条件范围内都明显地影响产品的收率;除了温度和搅拌转速外,其他参数都对产品粒度有较明显的影响;对产品粒度分布影响较大的是晶种加入量,温度和搅拌强度。通过分析各种因素影响得到泰乐菌素较佳结晶工艺条件:水和丙酮质量比4∶1,晶种加入量0.5%,结晶温度40℃,初始质量分数1.08 g/g,搅拌转速250 r/min,陈化时间12 h,流加速率先0.3 m L/min,后0.89 m L/min。 相似文献
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以雷别卡霉素和星形孢菌素为主要对象,陈述其合成过程中的基因、酶和中间产物。吲哚咔唑类化合物的生物合成主要分为吲哚环的形成、糖基的形成以及两者的连接。起始物色氨酸经过色氨酸修饰、双吲哚吡咯的形成和氧化环的闭合形成吲哚环,通过糖基转移酶将吲哚咔唑核心和糖基连接合成目标化合物。 相似文献
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Wu Y Kang Q Shang G Spiteller P Carroll B Yu TW Su W Bai L Floss HG 《Chembiochem : a European journal of chemical biology》2011,12(11):1759-1766
Ansamitocins are potent antitumor agents produced by Actinosynnema pretiosum. As deduced from their structures, an N‐methylation on the amide bond is required among the various modifications. The protein encoded by asm10 belongs to the SAM‐dependent methyltransferase family. Through gene inactivation and complementation, asm10 was proved to be responsible for the N‐methylation of ansamitocins. Asm10 is a 33.0 kDa monomer, as determined by gel filtration. By using N‐desmethyl‐ansamitocin P‐3 as substrate, the optimal temperature and pH for Asm10 catalysis were determined to be 32 °C and 10.0, respectively. Asm10 also showed broad substrate flexibility toward other N‐desmethyl‐ansamycins and synthetic indolin‐2‐ones. Through site‐directed mutagenesis, Asp154 and Leu155 of Asm10 were confirmed to be essential for its catalysis, possibly through the binding of SAM. The characterization of this unique N‐methyltransferase has enriched the toolbox for engineering N‐methylated derivatives from both natural and synthetic compounds; this will allow known potential drugs to be modified. 相似文献
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Kubota T Brünjes M Frenzel T Xu J Kirschning A Floss HG 《Chembiochem : a European journal of chemical biology》2006,7(8):1221-1225
The biosynthesis of the antitumor antibiotic, ansamitocin, involves the assembly of a linear octaketide on the ansamitocin (asm) polyketide synthase (PKS), which is then cyclized to proansamitocin and further modified to the final product. In the first chain-extension step on the asm PKS, a stereocenter is generated which is then obliterated in a subsequent double-bond migration. The cryptic configuration at this stereocenter was determined by first synthesizing the two enantiomers of the intermediate diketide as their N-acetylcysteamine (SNAC) thioesters. These were then used to demonstrate that only the R enantiomer complements a 3-amino-5-hydroxybenzoic acid (AHBA) deficient mutant of Actinosynnema pretiosum to restore ansamitocin formation. The low efficiency of complementation by the diketide, compared to AHBA, is due to inefficient loading onto the PKS and not the inhibition of the enzyme. A presumed next chain-extension intermediate-the triketide with an unrearranged double bond-was also synthesized as its SNAC ester, but did not complement the AHBA(-) mutant. 相似文献
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Knobloch T Harmrolfs K Taft F Thomaszewski B Sasse F Kirschning A 《Chembiochem : a European journal of chemical biology》2011,12(4):540-547
New ansamitocin derivatives were prepared by feeding aminobenzoic acid derivatives to cultures of Actinosynnema pretiosum HGF073, a mutant strain blocked in the biosynthesis of the required 3-amino-5-hydroxybenzoic acid (AHBA) starter unit. Use of several aminobenzoic acids as precursors led to a spectrum of products, reflecting the sequence of post-PKS tailoring steps involved in the generation of ansamitocins and adding novel aspects to the published suggestion model of post-PKS tailoring logic and flexibility. The studies provide insights into the substrate flexibility of the enzymes required for ansamitocin biosynthesis in A. pretiosum, whereas preliminary biological testing of the derivatives isolated and fully characterized by NMR spectroscopy allowed structure-activity relationship assignments to be made for a variety of intermediates occurring during the post-PKS tailoring sequence in ansamitocin biosynthesis. 相似文献
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微生物聚酯的合成和应用研究进展 总被引:11,自引:1,他引:11
微生物聚酯是由发酵技术生产、具有生物降解性的热塑性高分子材料。本文介绍了3-羟基丁酯均聚物(PHB)和共聚物的基本结构、生物降解性能、生物合成及其应用研究的进展。 相似文献