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新型微生物多糖胶联多糖 总被引:4,自引:0,他引:4
本文介绍了新型微生物多糖胶联多糖的结构、来源及生产,通过与其它水溶胶体的比较说明了它的溶液性质,凝胶性质,还涉及其商业可获性和安全性研究,并展望了它在食品中的应用前景。 相似文献
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仙草多糖的分离纯化及鉴定 总被引:6,自引:0,他引:6
仙草(Mesona Chiliensis Benth)是我国的一种民间草药。用0.5%NaHCO_3抽提,乙醇沉淀得到了仙草多糖的粗品。经过H_2O_2脱色处理,Sephadex G-75柱层析和硫酸—苯酚法收集单一峰部分,得到仙草多糖纯品(简称MCPS),薄层层析、凝胶电泳和醋纤薄膜电泳证明其为均一性多糖。红外光谱扫描表明,它具有典型的多糖吸收峰。HPLC法测得相对分子量为4.3×10~4,经薄层层析确定MCPS的单糖组成为葡萄糖、半乳糖、阿拉伯糖、木糖、鼠李糖,半乳糖醛酸及一种未知单糖。药理实验表明,它具有免疫促进作用与抑瘤效应。 相似文献
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螺旋藻的研究进展 总被引:8,自引:0,他引:8
崔俊屹 《天然产物研究与开发》1994,6(4):80-84
通过对螺旋藻的形态特征、产地、发展史、营养价值、药用价值以及其开发应用等情况的论述,阐明了螺旋藻作为一种新的蛋白质资源及药用资源,具有很高的开发利用价值,并且也对螺旋藻这种新资源的未来进行了展望。 相似文献
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多糖由于具有抗氧化、抗肿瘤、调节免疫、降血糖等生物活性而受到诸多领域的关注。多糖的结构与其生物活性相关,经过化学修饰会增强其生物活性或产生新的活性。本文就天然多糖的羧甲基化修饰及对其生物活性的影响进行综述,以期为多糖的研发与应用提供理论参考。 相似文献
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为了获得纯化多糖并对其空间结构进行研究,用煎煮法从海金沙草中提取水溶性粗多糖,考察了Savage法、TCA法、单宁法等方法对提取液中蛋白质去除率和多糖回收率的影响,用乙醇沉淀法获得精制多糖,紫外光谱扫描分析多糖纯度,刚果红结合实验分析多糖空间构象.结果表明,以TCA法蛋白质去除率和多糖回收率较高.紫外扫描图谱显示,纯化... 相似文献
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茯苓多糖抗氧化性研究 总被引:1,自引:0,他引:1
采用分光光度法研究了茯苓多糖提取物的体外抗氧化作用,并与Vc进行比较.结果表明其具有较强的抗氧化能力,在清除DPPH·的体系中和还原能力体系中,样品的清除能力均超过Vc,但在羟基自由基·OH和超氧阴离子O-2体系中,其清除能力低于对照样Vc. 相似文献
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夏枯草多糖的分离、纯化及结构初步分析 总被引:2,自引:0,他引:2
采用100℃热水提取,得到夏枯草粗多糖。经阴离子交换柱层析、凝胶过滤柱层析对粗多糖进行纯化分级,通过高效凝胶过滤色谱测得了其主要组分PLS3的重均分子量为8.3×10-5Da。对PLS3进行了红外分析,测定了其初步结构;并分别以气相色谱和柱前衍生化高效液相色谱法测定了粗多糖和PLS3的单糖组成,发现两者所含单糖种类一致,都为半乳糖、葡萄糖、甘露糖、木糖、阿拉伯糖、鼠李糖,但两种物质的单糖组成相对摩尔百分比有所差异。 相似文献
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党参类多糖比色法含量测定 总被引:7,自引:1,他引:6
党参的主要成分是糖类,传统经验认为,党参“味甜者佳”,其品质好坏,多以含糖量来衡量。药理研究表明,党参的升血糖作用是其所含糖分所致。刘中煜等曾对5种党参中单糖含量进行了测定,但其多糖含量测定尚无报道。本文采用苯酚一硫酸比色法对党参类多糖含量进行了测定。 相似文献
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Jian Guo Siyao Huang Yefu Chen Xuewu Guo Dongguang Xiao 《World journal of microbiology & biotechnology》2018,34(1):11
Pullulan produced by Aureobasidium pullulans presents various applications in food manufacturing and pharmaceutical industry. However, the pullulan biosynthesis mechanism remains unclear. This work proposed a pathway suggesting that heavy oil and melanin may correlate with pullulan production. The effects of overexpression or deletion of genes encoding apolipoprotein, UDPG-pyrophosphorylase, glucosyltransferase, and α-phosphoglucose mutase on the production of pullulan, heavy oil, and melanin were examined. Pullulan production increased by 16.93 and 8.52% with the overexpression of UDPG-pyrophosphorylase and apolipoprotein genes, respectively. Nevertheless, the overexpression or deletion of other genes exerted little effect on pullulan biosynthesis. Heavy oil production increased by 146.30, 64.81, and 33.33% with the overexpression of UDPG-pyrophosphorylase, α-phosphoglucose mutase, and apolipoprotein genes, respectively. Furthermore, the syntheses of pullulan, heavy oil, and melanin can compete with one another. This work may provide new guidance to improve the production of pullulan, heavy oil, and melanin through genetic approach. 相似文献
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Yefu Chen Jian Guo Feng Li Mingming Liu Xinxin Zhang Xuewu Guo Dongguang Xiao 《Biotechnology and Bioprocess Engineering》2014,19(2):282-288
Xylose, the second most abundant sugar in lignocellulosic materials, is not efficiently utilized in current lignocellulose biotransformation processes, such as cellulosic ethanol production. The bioconversion of xylose to value-added products, such as pullulan, is an alternative strategy for efficient lignocellulose biotransformation. This paper reports the production of pullulan from xylose and hemicellulose hydrolysate by Aureobasidium pullulans AY82. The effects of DL-dithiothreitol (DTT) and pH on pullulan production from xylose were also intensively investigated. A maximal increase of 17.55% of pullulan production was observed in flasks added with 1.0 mM DTT. Batch fermentations with controlled pH were also conducted, and the optimal pH for cell growth and pullulan synthesis was 3.0 and 5.0, respectively. Based on these findings, two-stage pH control fermentations were performed, in which the pH of the medium was first adjusted to 3.0 for cell growth, and then changed to 5.0 for pullulan synthesis. However, the earlier the pH was changed to 5.0, the more pullulan was produced. Fermentation with controlled pH of 5.0 acquired the highest pullulan production. Under the optimized conditions (with the addition of 1.0 mM DTT and controlled pH of 5.0), the maximal pullulan production obtained from xylose was 17.63 g/L. A. pullulans AY82 also readily fermented hemicellulose hydrolysate under these optimized conditions, but with lower pullulan production (12.65 g/L). Fourier transform infrared spectroscopy and high-performance liquid chromatography showed that the structure of the pullulan obtained in this study was identical to that of the pullulan standard. 相似文献
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Pullulan: biosynthesis,production, and applications 总被引:1,自引:0,他引:1
Pullulan is a linear glucosic polysaccharide produced by the polymorphic fungus Aureobasidium pullulans, which has long been applied for various applications from food additives to environmental remediation agents. This review
article presents an overview of pullulan’s chemistry, biosynthesis, applications, state-of-the-art advances in the enhancement
of pullulan production through the investigations of enzyme regulations, molecular properties, cultivation parameters, and
bioreactor design. The enzyme regulations are intended to illustrate the influences of metabolic pathway on pullulan production
and its structural composition. Molecular properties, such as molecular weight distribution and pure pullulan content, of
pullulan are crucial for pullulan applications and vary with different fermentation parameters. Studies on the effects of
environmental parameters and new bioreactor design for enhancing pullulan production are getting attention. Finally, the potential
applications of pullulan through chemical modification as a novel biologically active derivative are also discussed. 相似文献
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Protoplasts of Aureobasidium pullulans are capable of producing pullulan. Biosynthesis of the polymer pullulan required induction with kinetics similar to those of whole cells. The protoplasts also produced a heteropolysaccharide component containing mannose, glucose, and galactose. The relative proportions of the pullulan and heteropolysaccharide fractions were a function of glucose concentration, with the pullulan content of the total polysaccharide rising from 20% at 2.5 mM glucose to 45% at 20 mM glucose. Elaboration of pullulan by both cells and protoplasts was sensitive to 0.6 M KCl, which was present as the osmotic stabilizer in protoplast experiments. The presence of KCl resulted in a shift in the pH optimum to a more acidic value. The molecular weight of the protoplast-derived pullulan was sharply reduced from the molecular weight of the whole-cell-derived product. Exposure of the protoplasts to proteolytic enzymes had no effect on polysaccharide elaboration. 相似文献
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R. Gaur R. Singh S. Tiwari S.K. Yadav N.S. Daramwal 《Journal of applied microbiology》2010,109(3):1035-1043
Aims: To isolate the novel nonmelanin pullulan‐producing fungi from soil and to optimize the physico‐chemical and nutritional parameters for pullulan production. Methods and Results: A selective enrichment method was followed for the isolation, along with development of a suitable medium for pullulan production, using shake flask experiments. Pullulan content was confirmed using pure pullulan and pullulanase hydrolysate. Eurotium chevalieri was able to produce maximum pullulan (38 ± 1·0 g l?1) at 35°C, pH 5·5, 2·5% sucrose, 0·3% ammonium sulfate and 0·2% yeast extract in a shake flash culture medium with an agitation rate of 30 rev min?1 for 65 h. Conclusions: The novel pullulan‐producing fungus was identified as E. chevalieri (MTCC no. 9614), which was able to produce nonmelanin pullulan at from poorer carbon and nitrogen sources than Aureobasidium pullulans and may therefore be useful for the commercial production of pullulan. Significance and Impact of the Study: Eurotium chevalieri could produce pullulan in similar amounts to A. pullulans. Therefore, in future, this fungus could also be used for commercial pullulan production, because it is neither polymorphic nor melanin producing, hence its handling during pullulan fermentation will be easier and more economical. 相似文献
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Summary Pullulan is a polysaccharide produced by Aureobasidium pullulans. In this study, the effect of pH on the molecular weight of pullulan was investigated. High concentration of pullulan was obtained when initial pH was 6. Pullulan having molecular weight of 500,000–600,000 was produced at initial pH of 3.0, while pullulan with molecular weight of 200,000–300,000 was produced at pH above 4.5. To obtain high molecular weight pullulan with high concentration, pH was initially controlled at pH 6, followed by pH shift from pH 6 to pH 3. Transition of pH at 2 days of fermentation was observed to be optimum. Higher molecular weight pullulan was also obtained when sucrose concentration was 50 g/l compared to the result obtained at initial sucrose concentration of 20 g/l. Sucrose concentration and pH of the fermentation broth seem to be important parameters in obtaining high molecular weight of pullulan. 相似文献
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Effects of different pH and carbon sources on pullulan production, UDP-glucose level and pullulan-related synthases activity inAureobasidium pullulans Y68 were examined. It was found that more pullulan was produced when the yeast strain was grown in the medium with initial pH 7.0 than when it was grown in the same medium with constant pH 6.0. The results also show that higher pullulan yield was obtained when the cells were grown in the medium containing glucose than when they were cultivated in the medium supplementing other carbon sources. Our results demonstrate that the more pullulan was synthesized, the less UDP-glucose was left in the cells ofA. pullulans Y68. However, it was observed that more pullulan was synthesized; the cells had higher pullulan-related synthase activity. Therefore, high pullulan yield was related to low UDP-glucose level and high pullulan-related synthases activity inAureobasidium pullulans Y68. 相似文献