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《制药原料及中间体信息》2007,(6):13-15
近期,许多维生素品种的价格行情纷纷看涨,就连长期在低谷徘徊的维生素C也开始复苏。作为维生素家族的一个小类品种,核黄素(维生素B2)也在持续提价,预计在未来两年内,核黄素的价格还将继续在高位运行。据统计,全球核黄素的市场规模在2002年约为1亿美元, 相似文献
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核黄素作为药品、色素、营养及动物饲料添加剂被广泛应用,目前生产及销售的核黄素基本上都是针状晶习,其堆密度小、分散性和流动性差,影响压片等加工性能。本文对酸溶法、碱溶法等5种核黄素结晶纯化方法进行了筛选,发现酸溶法收率和纯度的综合效益最佳;在此基础上采用超声辅助结晶,对功率、时间及温度进行优化,通过透射电镜(TEM)及X射线衍射分析法(XRD)等表征方法对结果进行分析。最终确定超声结晶的最佳实验条件为:超声功率为400W,超声时间为40min,超声温度为50℃,核黄素的收率可达到95%,纯度超过96%。核黄素晶习和结晶度有所改善,便于加工应用。 相似文献
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核黄素的循环伏安法分析 总被引:1,自引:0,他引:1
介绍了在 NH3 · H2 O- NH4 Cl( PH=1 0 )缓冲溶液中的核黄素 (维生素 B2 )循环伏安图 ;核黄素在 - 0 .545V( VS.Ag Cl/Ag)产生一个阴极峰 ;在 - 0 .50 6 V产生一个阳极峰。其波高与核黄素溶液的浓度分别在 6× 1 0 - 7~ 7× 1 0 - 6mol· l- 1和 4× 1 0 - 7~ 8× 1 0 - 6mol· l- 1范围内成线性关系 ,检测限分别为 4× 1 0 - 7mol· l- 1和 2× 1 0 - 7mol· l- 1。 相似文献
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全文介绍了核黄素的性能,生产的主要技术路线与最佳的操作条件及有关进展情况。对现工业化运行的主要核黄素生产工艺的技术特点进行了具体的分析和总结,阐述了国内外开发的现状与发展趋势。并探讨了扩大应用范围等的前景与市场需求。 相似文献
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介绍了核黄素的一些药理作用及应用前景。根据配位原理研究核黄素与氨基酸如色氨酸的二元体系的络合情况。利用紫外可见光谱在室温条件下,采用相同的给体体积配比、不同的浓度配比,随着给体的浓度不断增大,通过测定其吸光度找出吸光度与浓度配比的规律。对紫外光谱图进行比较,在实验中找到了核黄素与氨基酸络合的一些规律。 相似文献
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利用PCR技术从枯草芽孢杆菌(Bacillus subtilis 168)中扩增出3.5 kb的核黄素操纵子,将其分别连接到不同拷贝数的表达载体pSC101、p15A、pBR322,得到重组载体pSC101-BSrib、p15A-BSrib和pBR322-BSrib,并分别转化到大肠杆菌(Escherichia coli K-12 MG1655)。对含有核黄素操纵子的重组大肠杆菌进行摇瓶发酵,结果表明其核黄素合成能力随着质粒拷贝数的增加而增强。随后对E. coli K-12 MG1655 ECX3菌株的诱导剂IPTG浓度和发酵温度进行了优化。结果显示,0.1 mmol·L-1 IPTG和42 ℃为核黄素生产的最适宜条件。在此条件下,菌株ECX3在LB培养基中核黄素产量达到251.4 mg·L-1。最后,通过无痕基因操作技术,减弱了工程菌株ECX3核黄素激酶/黄素腺嘌呤二核苷酸氨酰转移酶(ribF)的表达以减少核黄素转化为FMN和FAD,摇瓶中工程菌株ECX4的核黄素产量提高到292.3 mg·L-1。 相似文献
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对固体超强酸ZrO_2-SO_4~(2-)催化合成核黄素四乙酸酯进行了研究。核黄素与乙酸酐摩尔比1:40,催化剂用量为反应物总质量的8.0%,反应温度80℃,反应时间2.5h,核黄素四乙酸酯产率可达76.9%。ZrO_2SO_4~ ̄(2-)催化活性高于TiO_2-SO_4~(2-)和Fe_2O_3-,SO_4~(2-)ZrO_2在1mol/LH_2 SO_4中浸渍 24h,600℃焙烧 3h催化活性最高。 相似文献
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综合应用基因组改组和DNA重组技术改进了核黄素生产菌B.subtilis 24/pMX45的性状,在B.subtilis染色体上整合和扩增了多个B.subtilis 24的核黄素操纵子拷贝,并经过两轮的基因组改组后筛得菌株B.subtilis RH33/pMX45,在以12%葡萄糖为碳源的分批发酵中,其核黄素产量约为B.subtilis 24/pMX45的2倍,并具有快速同化利用葡萄糖、生长迅速、可形成感受态和进行基因整合、扩增等优良性状.随后比较分析了三株产核黄素B.subtilis在间歇培养条件下的代谢通量分布,通量分析和实验结果表明,B.subtilis RH33/pMX45中核黄素合成的主要通量限制因素存在于从5-磷酸核酮糖到GTP的一系列反应中. 相似文献
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用盐酸溶液对枸杞样品中的核黄素进行提取,通过正交试验讨论了盐酸溶液浓度和搅拌时间以及料液比对提取结果的影响。确定最佳实验条件为0.075mol/L盐酸溶液作为提取溶剂,料液比为1∶20(g/mL),搅拌提取30min。在激发波长λex=490.0nm,发射波长λem=512.0nm下对核黄素进行荧光分析测定。方法的线性相关系数r2=0.9993,平均加标回收率为97.5%。该方法用于枸杞样品中核黄素的检测,操作方法简单易行,测定速度快,分析结果良好。 相似文献
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Dr. Chengchang Zhang Dr. Meiling Lu Dr. Lin Lin Prof. Dr. Zhangjian Huang Prof. Dr. Rongguang Zhang Dr. Xuri Wu Prof. Dr. Yijun Chen 《Chembiochem : a European journal of chemical biology》2020,21(16):2297-2305
Like a vast number of enzymes in nature, bacterial cytochrome P450 monooxygenases require an activated form of flavin as a cofactor for catalytic activity. Riboflavin is the precursor of FAD and FMN that serves as indispensable cofactor for flavoenzymes. In contrast to previous notions, herein we describe the identification of an electron-transfer process that is directly mediated by riboflavin for N-dealkylation by bacterial P450 monooxygenases. The electron relay from NADPH to riboflavin and then via activated oxygen to heme was proposed based on a combination of X-ray crystallography, molecular modeling and molecular dynamics simulation, site-directed mutagenesis and biochemical analysis of representative bacterial P450 monooxygenases. This study provides new insights into the electron transfer mechanism in bacterial P450 enzyme catalysis and likely in yeasts, fungi, plants and mammals. 相似文献
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《分离科学与技术》2012,47(11):2681-2694
Abstract A batch recovery of riboflavin via foam separation from industrial simulative wastewater was studied using a cationic surfactant, cetyltrimethyl ammonium bromide (CTAB). The experimental parameters examined were the surfactant concentration, air flow rate, pH, and foam height. Under optimal operating conditions obtained through an orthogonal experiment, the maximum enrichment ratio of 48.7 was achieved for riboflavin along with 99.3% removal efficiency. The optimal operating conditions had the concentration of CTAB at 0.3 g/L, air flow rate at 400 ml/min, foam height at 90 cm, and pH at 12. Therefore foam separation proved to be an effective method to recover the riboflavin in terms of the good enrichment and removal efficiency. 相似文献
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María Paz San Andrs Marina Baos-Cabrera Lucía Gutirrez-Fernndez Ana María Díez-Pascual Soledad Vera-Lpez 《International journal of molecular sciences》2021,22(10)
The potential of tannic acid (TA) as a dispersing agent for graphene (G) in aqueous solutions and its interaction with riboflavin have been studied under different experimental conditions. TA induces quenching of riboflavin fluorescence, and the effect is stronger with increasing TA concentration, due to π-π interactions through the aromatic rings, and hydrogen bonding interactions between the hydroxyl moieties of both compounds. The influence of TA concentration, the pH, and the G/TA weight ratio on the quenching magnitude, have been studied. At a pH of 4.1, G dispersed in TA hardly influences the riboflavin fluorescence, while at a pH of 7.1, the nanomaterial interacts with riboflavin, causing an additional quenching to that produced by TA. When TA concentration is kept constant, quenching of G on riboflavin fluorescence depends on both the G/TA weight ratio and the TA concentration. The fluorescence attenuation is stronger for dispersions with the lowest G/TA ratios, since TA is the main contributor to the quenching effect. Data obey the Stern–Volmer relationship up to TA 2.0 g L−1 and G 20 mg L−1. Results demonstrate that TA is an effective dispersant for graphene-based nanomaterials in liquid medium and a green alternative to conventional surfactants and synthetic polymers for the determination of biomolecules. 相似文献