安徽省三种产地竹黄菌培养的初步研究

首次对安徽省三种产地的竹黄菌进行了组织分离培养和液体发酵,比较了该菌固体生长状况和液体发酵形成的竹红菌素产量。结果显示,广德卢村的菌种平皿生长速度为0．31cm／d,液体发酵产生的竹红菌素吸光度为0．21;宁国板桥菌种平皿生长速度为0．30cm／d,液体发酵产生的竹红菌素吸光度为0．30;休宁武城的竹黄菌平皿生长速度为1．85cm／d,菌株液体发酵产生的竹红菌素吸光度为O．39。结论表明,休宁武城菌种无论是平皿生长速度还是发酵形成的竹红菌素量都明显优于其它两地的菌株。     

竹黄菌液体发酵条件的优化

目的：筛选并优化竹黄菌液体发酵培养基。方法：采用单因子和3因素3水平正交试验法,从生物量和竹红菌素两方面筛选碳源、氮源和pH,探讨该菌生长的最佳培养条件。结果：最佳发酵碳源是葡萄糖,最佳发酵氮源是硝酸钠。竹红菌素生长的最佳配方为2%葡萄糖,0.2%硝酸钠,pH7.5;菌丝体生长的最佳组合为2%葡萄糖,0.3%硝酸钠,pH7.5。     

竹黄菌液体培养下产竹红菌素的研究

先对不同产地采集的竹黄菌进行筛选,得到优产竹红菌素的菌株,然后采用单因子和3因素3水平正交试验法对竹红菌素液体发酵条件进行优化,在优化培养基的基础上,选用不同浓度的Cr3+、Fe3+、Cu2+和Ca2+对竹红菌素进行离子调控研究。结果表明:从休宁所采集的菌株不仅生长速度最快,发酵所产的竹红菌素含量也最高;竹红菌素最佳发酵碳源是葡萄糖,最佳发酵氮源是硝酸钠,最佳培养基组合为2%葡萄糖,0.2%硝酸钠,pH7.5;Cr3+和Fe3+浓度为0.005%时竹红菌素含量均最高;0.05%的Ca2+最有利于竹红菌素的分泌;Cu2+为0.03%时竹红菌素含量达到最大值。     

Study on fermentation hypocrellin by Shiraia bambusicola in submerged cultures

先对不同产地采集的竹黄菌进行筛选,得到优产竹红菌素的菌株,然后采用单因子和3因素3水平正交试验法对竹红菌素液体发酵条件进行优化,在优化培养基的基础上,选用不同浓度的Cr3+、Fe3+、Cu2+和Ca2+对竹红菌素进行离子调控研究.结果表明:从休宁所采集的菌株不仅生长速度最快,发酵所产的竹红菌素含量也最高;竹红菌素最佳发酵碳源是葡萄糖,最佳发酵氮源是硝酸钠,最佳培养基组合为2%葡萄糖,0.2%硝酸钠,pH7.5;Cr3+和Fe3+浓度为0.005%时竹红菌素含量均最高;0.05%的Ca2+最有利于竹红菌素的分泌;Cu2+为0.03%时竹红菌素含量达到最大值.     

竹黄菌发酵生产竹红菌素的研究进展

竹黄作为名贵中药,其主要成分竹红菌素是优良的天然光敏药物。由于天然竹黄资源有限,通过竹黄无性型菌株发酵生产竹红菌素因而受到广泛关注。通过介绍竹黄无性型菌株的固态、液态发酵,分析了竹红菌素发酵生产的各种影响因子,并对竹红菌素合成诱导物质及高产菌株诱变筛选等进行了综述,为竹红菌素合成调控和发酵生产提供了参考。     

竹黄遗传多样性与竹红菌素合成和抗癌作用的研究进展

竹黄在我国是一种重要的药用真菌,主要活性代谢产物为竹红菌素等苝醌类光敏色素。前人关于竹黄的研究主要集中在活性成分分析、临床应用和发酵培养等方面。竹黄遗传多样性的存在是不同居群、不同菌株之间竹红菌素生物合成代谢差异的原因,并且随着竹红菌素及其衍生物对肿瘤细胞的抑制机制被不断揭示,对于竹黄的遗传多样性、竹红菌素的合成代谢与抗癌作用机理等研究正持续深入。应用不同的分子标记发现,竹黄遗传多样性既可能来源于居群内,也可能来源于居群间;而通过化学修饰或物理修饰都使竹红菌素在肿瘤的光动力治疗(Photodynamic therapy,PDT)上展现出诱人的前景。同时,影响竹红菌素产生的聚酮合酶基因等新的研究发现最终将会有助于掌握竹黄中竹红菌素的生物合成途径。综述了竹黄的遗传多样性、竹红菌素及其衍生物对癌细胞的作用和竹红菌素生物合成的研究进展,旨在为竹黄的资源保育和竹红菌素的深入研发提供参考。     

Shiraia sp．SUPER—H168 ITS-5．8S rDNA序列分析及产竹红菌素条件初步优化

对产竹红菌素的菌株SUPER-H168的ITS-5．8S rDNA进行了序列测定和进化树聚类分析,表明其属于竹黄属;对该菌株固态发酵产竹红菌素的条件进行了初步优化,得到的初步优化条件为玉米渣25g,麸皮5g,葡萄糖1．5g,NaNO3 0．15g,ZnSO4·7H2O 0．03g,起始含水量为50％,起始pH为7．0,培养温度为30℃。在该条件下发酵18d,竹红菌素的产量为9．37mg／g干基。     

Shiraia sp.SUPER-H168液态发酵产竹红菌素过程中生理特征初步研究

通过对竹黄菌株SUPER-H168产竹红菌素及不产竹红菌素时生理特征的研究,发现MDA、胞内及胞外的总抗氧化力、过氧化氢、维生素C的含量均比对照组高;CAT的活力上升,而SOD活力总体稍有下降。实验结果表明,菌体产竹红菌素初期伴随着其自身氧化水平的上升。添加终浓度为40μmol/L的过氧化氢可以促进竹红菌素生成。     

一株竹黄无性型菌株液态发酵产竹红菌素的初步研究

从野生竹黄子座中分离获得能产生竹红菌素的无性型菌株ZH-5-1,经液态发酵培养及摇瓶正交试验确定最佳培养基配方和培养条件:葡萄糖30g/L,蛋白胨5g/L,NaNO3 10g/L,KCl 1.5g/L,MgSO4 1.5g/L,KH2PO4 2g/L,pH 值6.0,装液量100/250 mL(V/V),接种量10%(V/V),培养温度28℃,摇床转速130 r/min,培养周期96h.     

药用竹黄菌的生物学研究进展

对药用真菌竹黄菌的分类学地位,竹黄菌的寄主及生态学,竹红菌素、竹黄菌多糖、竹黄菌的抗菌谱等生物活性物质,竹黄人工培养的生物学研究进展进行了综述。提出了自然界是否存在着竹黄新种属和寄主专一性目前竹黄尚处于自生自灭状态,子座尚未能人工培养,不利竹黄物种和药源保护与可持续利用等问题;指明今后还需深入开展竹黄菌的生物学研究和探索竹黄人工培养技术,以利竹黄的开发、利用。     

Structured modeling of a microbial system: I. A theoretical study of lactic acid fermentation

Most fermentation models presented in the literature are unstructured, i.e., the biomass composition is assumed constant during all operating conditions. These models are unable to simulate experiments carried out at widely different operating conditions. It is therefore interesting to examine simple structured models where knowledge of the cell physiology is taken into account in the modeling phase. In this article, a simple structured model is presented. The model is based on experimental work with the lactic acid bacteria Streptococcus cremoris, but due to the similarities in basic metabolism for many microorganisms it is applicable also for other fermentation system. The basic assumption in the model is that the biomass can be divided into two parts (compartments)-an active part and a mainly inactive structural part. The size of the active part has a pivotal role in the model.     

丙酸絮凝发酵新工艺研究

报道了丙酸发酵的一种新工艺:絮凝发酵工艺。采用谢氏丙酸杆菌(Propionibacterium shermanii)W125在批次发酵产酸达到29g/L的基础上,选择氢氧化钙作为中和剂兼絮凝剂,建立了絮凝半连续发酵工艺,连续运行250h,产酸量达到了35.4g/L,产酸率提高了22%,糖酸转化率达到了51.56%,体积效率达到了0.37g/(L/h)。     

重组巴斯德毕赤酵母高密度发酵表达植酸酶

对巴斯德毕赤酵母的高密度发酵条件进行了试验,并根据摇瓶发酵的优化结果进行了补料方式的研究。在摇瓶发酵时,最佳种龄为16h,接种量为3％,甲醇的诱导浓度为15g／L,生长阶段最适pH为5．0,诱导阶段最适pH为5．5。在间歇补料、恒速补料、变速补料三种补料方式中以变速流加最优。     

Relevance of microbial coculture fermentations in biotechnology

The purpose of this article is to review coculture fermentations in industrial biotechnology. Examples for the advantageous utilization of cocultures instead of single cultivations include the production of bulk chemicals, enzymes, food additives, antimicrobial substances and microbial fuel cells. Coculture fermentations may result in increased yield, improved control of product qualities and the possibility of utilizing cheaper substrates. Cocultivation of different micro‐organisms may also help to identify and develop new biotechnological substances. The relevance of coculture fermentations and the potential of improving existing processes as well as the production of new chemical compounds in industrial biotechnology are pointed out here by means of more than 35 examples.     

Optimization of a two-stage recombinant fermentation process: the dilution rate effect

The effects of dilution rates on the performance of a two-stage fermentation system for a recombinant Escherichia coli culture were studied. Dilution rate determines the apparent or averaged specific growth rate of a heterogeneous population of cells in the recombinant culture. The specific growht rate affects the genetic parameters involved in product formation in the second stage, such as plasmid stability, plasmid content, and specific gene expression rate. Kinetic models and correlations were developed for these parameters based on experimental data. Simulations of plasmid stability in the first stage showed that for longer fermentation periods, plasmid stability is better at higher dilution rates. However, the plasmid content is lower at these dilution rates. The optimal apparent specific growth rate for maximum productivity in the second stage was determined using two methods: (1) direct search for a constant specific growth rate, and (2) dynamic optimization using the maximum principle for a time-dependent specific growth rate profile. The results of the calculations showed that the optimum constant apparent specific growth rate for maximum over-all productivity is 0.40 h(-1). This coincides with the optimal specific growht rate for maximum plasmid content in the expressed stage. A 3.5% increase in overall productivity can be obtained by using a linear time dependent apparent specific growth rate control, mu(2)(t) = 0.0007t, in the course of the fermentation time.     

Optimization of an industrial microalgae fermentation

Optimization of cellular productivity of an industrial microalgae fermentation was investigated. The fermentation was carried out at Coors Biotech Products Company, Fort Collins, Colorado. A mathematical model was developed based on the data collected from pilot plant test runs at different operating conditions. Pontryagin's maximum principle was used for determining the optimal feed policy. A feedback control algorithm was also studied for maximizing the cellular productivity. During continuous operation, the optimum dilution rate was determined by an adaptive optimization scheme based on the steepest descent technique and a recursive least squares estimation of model parameters. A direct search algorithm was also applied to determine the optimum feed rate. Comparison of the theoretical results of the different optimization schemes revealed that the direct search algorithm was preferable because of its simplicity. The experimental results of real time application of the feedback algorithm agreed fairly well with those of the theoretical analyses. (c) 1994 John Wiley & Sons, Inc.     

Mathematical model of self-cycling fermentation

This article presents a mathematical model for biomass, limiting substrate, and dissolved oxygen concentrations during stable operation of self-cycling fermentation (SCF). Laboratory experiments using the bacterium Acinetobacter calcoaceticus RAG-1 and ethanol as the limiting substrate were performed to validate the model. A computer simulation developed from the model successfully matched experimental SCF intracycle trends and end-of-cycle results and, most importantly, settled into an unimposed periodicity characteristic of stable SCF operation. (c) 1995 John Wiley & Sons, Inc.