霍山铁皮石斛糖蛋白的制备及抗氧化活性

以霍山铁皮石斛枫斗为试验材料,经脱脂脱色、0.3 mol/L盐溶液浸提、Sevage法脱蛋白、硫酸铵分级沉淀、透析、聚乙二醇10000浓缩、冷冻干燥得到粗品;经SDS PAGE电泳、DEAE 52离子柱和Sephadex G 100凝胶柱分离纯化得到糖蛋白并测定其抗氧化活性.SDS PAGE电泳显示硫酸铵饱和度越大,盐...     

酿酒酵母呼吸缺陷型和野生型酒精发酵特性的比较分析*

比较了酒精发酵生产菌株IFFI1300及其呼吸缺陷型突变株在酒精产量、发酵动力学、耐酒精能力及与酒精发酵相关的乙醇脱氢酶活性等方面的特性。结果表明：1)发酵终期的酒精产量,45株呼吸缺陷型的平均值与野生型没有显著性差异;但部分缺陷型的酒精产量高于野生型。2)酒精发酵动力学结果显示,呼吸缺陷型酒精产生速度略高于野生型。3)单位重量干菌体的乙醇脱氢酶活性,呼吸缺陷型高于野生型。以上结果提示：呼吸缺陷型用于酒精发酵以提高酒精产量和缩短发酵周期是有潜力的。4)单位体积发酵液的乙醇脱氢酶活性则野生型高于呼吸缺陷型,主要原因在于呼吸缺陷型的生物量明显低于野生型。5)呼吸缺陷型菌株之间的耐酒精能力差别很小,耐酒精能力的高低与酒精产量的高低没有明显的正相关性。一般的,酒精产量高的菌株耐酒精能力较强。在实验结果的基础上,对呼吸缺陷型用于酒精发酵的优越性和可行性进行了讨论。     

刺梨自然发酵过程中非酿酒酵母多样性分析

【目的】分析刺梨果实自然发酵过程中非酿酒酵母菌群特征,为筛选优质刺梨非酿酒酵母提供参考。【方法】基于Illumina MiSeq高通量测序技术和WL营养琼脂鉴定培养基纯种分离技术,分析刺梨果实自然发酵1 d(F1)、3 d(F3)、5 d(F5)和15 d(F15)4个阶段及YPD培养基富集培养样本中非酿酒酵母种群组成和多样性。【结果】高通量测序分析结果共获得182个OTUs(operational taxonomic units,OTUs),归属于81个属107个种;物种多样性分析结果表明,刺梨果实自然发酵前期,优势非酿酒酵母为汉逊酵母(Hanseniasporasp.)和伯顿丝孢毕赤酵母(Hyphopichiaburtonii),二者在样本F1中分别占42.59%和26.85%;随着自然发酵的不断进行,二者的比例逐渐降低,在第15天(F15),Hanseniaspora sp.和H.burtonii比例降低至7.73%和0.52%。相反,Pichia sporocuriosa和未培养的酵母,随着自然发酵不断进行所占比例逐渐增大,分别由F1中的0.23%和0.33%增至F15中的37.26%和32.62%。此外,采用WL营养琼脂鉴定培养基纯种分离和鉴定技术,从刺梨上分离到Hanseniasporasp.、H.burtonii、克鲁维毕赤酵母(Pichia kluyveri)、P.sporocuriosa和异常威克汉姆酵母(Wickerhamomyces anomalus)5种类型的可培养非酿酒酵母。【结论】刺梨果实上存在着丰富的非酿酒酵母菌资源,研究刺梨自然发酵过程中非酿酒酵母多样性,为酵母资源开发和利用奠定基础。     

无花果酵素自然发酵过程中代谢产物与抗氧化活性的相关性研究CSCD

为了解无花果自然发酵过程中代谢产物与抗氧化活性之间的相关性,测定其发酵过程中pH、总酸、总糖、总酚、总黄酮、有机酸等理化指标和活性物质,以DPPH自由基、羟基自由基和超氧自由基清除能力及还原力这4个指标考察其体外抗氧化能力,利用主成分分析方法,对代谢产物和抗氧化活性进行相关性分析,并对无花果酵素发酵的各个过程进行综合性评价,确定自然发酵最优的发酵时间。结果表明:随着发酵时间的延长,pH持续降低,总黄酮呈现波动变化,总酸、总酚、DPPH自由基、羟基自由基、超氧自由基清除能力和还原力均呈现先升高后降低的趋势。无花果酵素中检测出了13种主要有机酸,其中含量比较丰富的是乳酸、琥珀酸、苹果酸、柠檬酸、葡萄糖醛酸和泛酸。在发酵第60天时,综合评价值(CEI)最高,发酵80天之后持续下降,以此可以作为无花果酵素前发酵结束的依据,为无花果酵素发酵阶段精准调控奠定相关理论基础。     

酿酒酵母单倍体与双倍体原生质体的融合*

本文报道用酿酒酵母(Saccharomyces cerevisiae)原生质体融合,得到营养互补的融合子为三倍体,其生长速度、发酵速率均较亲株提高1—2倍。部分融合子酒精的产量高于亲株,同时高于目前使用的酒精发酵生产菌株。     

琥珀酸发酵研究进展*

琥珀酸在化工和食品行业应用广泛。与传统化学方法相比,微生物发酵法生产琥珀酸具有诸多优点：生产成本具有竞争力;利用可再生的农业资源包括二氧化碳作为原料,避免了对石化原料的依赖;减少了化学合成工艺对环境的污染。主要介绍产琥珀酸微生物的来源和育种,代谢途径和发酵调控机制以及产品回收工艺的进展。     

中国传统酸肉发酵过程中微生物的消长变化*

对我国传统发酵酸肉中的微生物种群进行了研究,从中分离到大量的米酒乳杆菌、戊糖片球菌、乳酸片球菌、明串珠菌等多种乳酸细菌和德巴利氏酵母、球拟酵母等微生物,这些微生物在发酵过程中有一个动态的变化。发酵全过程中优势微生物种群是乳酸细菌、微球菌、德巴利氏酵母和球拟酵母,为高效天然肉品发酵剂的研究与开发提供了生物资源。     

酿酒酵母220菌株对铅的生物吸附研究*

在含铅培养基中培养酿酒酵母220,发现该菌对铅有一定的抗性。将培养好的酿酒酵母220接入含铅培养基中并对该菌吸附铅的能力进行研究,结果表明,在30℃时,该菌对6mg/L的含铅溶液有最大的吸附率,吸附率为96．6％,吸附平衡时间为25～30min,吸附的动力学方程为q=26．318C／(1 0．437C),乙酸对吸附后的酿酒酵母220有良好的解吸作用,葡萄糖和KH2PO4可以提高酿酒酵母220对铅的吸附率。     

霍山石斛产业化发展的问题与对策

介绍了霍山石斛的概况,阐述了霍山石斛产业化发展的重要性和可行性。在分析了霍山石斛资源状况的基础上,着重剖析了霍山石斛产业化发展面临的主要问题,提出了相应的对策措施,旨在为霍山石斛的产业化开发与持续利用提供依据。     

Reaction kinetics of -glucose fermentation by Saccharomyces cerevisiae

Data obtained on the conversion of -glucose to alcohol using Saccharomyces cerevisiae in batch culture has been analysed kinetically. The effects of different kinetic parameters, e.g. rates of ethanol and biomass formation, rate of -glucose utilization and variation of pH have been studied. Analysis of data was made on the basis of Michaelis-Menten, Leudeking-Piret and simple kinetics. Unsteady rate behaviour in the lag phase was observed and explained.     

Sympatric natural Saccharomyces cerevisiae and S. paradoxus populations have different thermal growth profiles

Saccharomyces cerevisiae and its close congener S. paradoxus are typically indistinguishable by the phenotypic criteria of classical yeast taxonomy, but they are evolutionarily distinct as indicated by hybrid spore inviability and genomic sequence divergence. Previous work has shown that these two species coexist in oak-associated microhabitats at natural woodland sites in North America. Here, we show that sympatric populations of S. cerevisiae and S. paradoxus from a single natural site are phenotypically differentiated in their growth rate responses to temperature. Our main finding is that the S. cerevisiae population exhibits a markedly higher growth rate at 37 degrees C than the S. paradoxus population; we also find possible differences in growth rate between these populations at two lower temperatures. We discuss the implications of our results for the coexistence of these yeasts in natural environments, and we suggest that thermal growth response may be an evolutionarily labile feature of these organisms that could be analyzed using genomic approaches.     

酿酒酵母菌培养条件的研究

目的：优化酿酒酵母液体发酵得到菌体的最佳条件。方法：通过单因素试验,以吸光度为指标,研究碳源、氮源、接种量、pH值及无机离子对酿酒酵母菌生长的影响。结果：酿酒酵母生长的最佳碳源是葡萄糖,最佳氮源是蛋白胨,最佳接种量2％,最佳初始pH为4．5,添加无机盐硫酸亚铁能够促进其生长。结论：得到了酿酒酵母液体生长的最佳培养基配方。     

Characterization of gamma-glutamylamidase-glutaminase activity in Saccharomyces cerevisiae

In a foregoing paper we have shown the presence in the yeast Saccharomyces cerevisiae of an enzyme catalyzing the hydrolysis of L-gamma-glutamyl-p-nitroanilide, but apparently distinct from gamma-glutamyltranspeptidase. The cellular level of this enzyme was not regulated by the nature of the nitrogen source supplied to the yeast cell. Purification was attempted, using ion exchange chromatography on DEAE Sephadex A 50, salt precipitations and successive chromatographies on DEAE Sephadex 6B and Sephadex G 100. The apparent molecular weight of the purified enzyme was 14,800 as determined by gel filtration. As shown by kinetic studies and thin layer chromatography, the enzyme preparation exhibited only hydrolytic activity against gamma-glutamylarylamide and L-glutamine with an optimal pH of about seven. Various gamma-glutamylaminoacids, amides, dipeptides and glutathione were inactive as substrates and no transferase activity was detected. The yeast gamma-glutamylarylamidase was activated by SH protective agents, dithiothreitol and reduced glutathione. Oxidized glutathione, ophtalmic acid and various gamma-glutamylaminoacids inhibited competitively the enzyme. The activity was also inhibited by L-gamma-glutamyl-o-(carboxy)phenylhydrazide and the couple serine-borate, both transition-state analogs of gamma-glutamyltranspeptidase. Diazooxonorleucine, reactive analog of glutamine, inactivated the enzyme. The physiological role of yeast gamma-glutamylarylamidase-glutaminase is still undefined but is most probably unrelated to the bulk assimilation of glutamine by yeast cells.     

影响酵母细胞麦角固醇的发酵控制参数的分析

研究了麦角固醇发酵过程中的参数。比较了溶氧、OUR、Ph和残糖浓度与酿酒酵母的生物量和麦角固醇含量的关系 ,并研究了这些参数之间的内在联系。研究表明 ,溶氧能比较准确地反映酵母的生长状况 ,是发酵过程中的一个较好的控制参数。将溶氧控制在 12 %左右能有效提高单位体积发酵液中的麦角固醇的产量。     

Acetaldehyde production in Saccharomyces cerevisiae wine yeasts

Abstract Eighty-six strains of Saccharomyces cerevisiae were investigated for their ability to produce acetaldehyde in synthetic medium and in grape must. Acetaldehyde production did not differ significantly between the two media, ranging from a few mg/l to about 60 mg/l, and was found to be a strain characteristic. The fermentation temperature of 30°C considerably increased the acetaldehyde produced. This study allowed us to assign the strains to different phenotypes: low, medium and high acetaldehyde producers. The low and high phenotypes differed considerably also in the production of acetic acid, acetoin and higher alcohols and can be useful for studying acetaldehyde production in S. cerevisiae , both from the technological and genetic point of view.     

酿酒酵母生物合成胞磷胆碱的条件优化

通过优化胞磷胆碱底物浓度的发酵条件,提高酿酒酵母发酵菌浓及胞磷胆碱转化率.分别以胞苷酸、磷酸胆碱、硫酸镁和乙醇等底物和反应关联物质诱导酿酒酵母,采用单因素变量实验优化发酵条件.优化后,酿酒酵母C401菌株摇瓶培养的菌浓为70 g/L,胞磷胆碱转化率为53.3％,比诱导前提高了33.5％.30 L发酵中菌浓可达90.5 g/L,胞磷胆碱转化率为59％.     

Ethanol production by Saccharomyces cerevisiae in biofilm reactors

Biofilms are natural forms of cell immobilization in which microorganisms attach to solid supports. At ISU, we have developed plastic composite-supports (PCS) (agricultural material (soybean hulls or oat hulls), complex nutrients, and polypropylene) which stimulate biofilm formation and which supply nutrients to the attached microorganisms. Various PCS blends were initially evaluated in repeated-batch culture-tube fermentation with Saccharomyces cerevisiae (ATCC 24859) in low organic nitrogen medium. The selected PCS (40% soybean hull, 5% soybean flour, 5% yeast extract-salt and 50% polypropylene) was then used in continuous and repeated-batch fermentation in various media containing lowered nitrogen content with selected PCS. During continuous fermentation, S. cerevisiae demonstrated two to 10 times higher ethanol production in PCS bioreactors than polypropylene-alone support (PPS) control. S. cerevisiae produced 30 g L⁻¹ ethanol on PCS with ammonium sulfate medium in repeated batch fermentation, whereas PPS-control produced 5 g L⁻¹ ethanol. Overall, increased productivity in low cost medium can be achieved beyond conventional fermentations using this novel bioreactor design. Received 20 May 1997/ Accepted in revised form 29 August 1997     

啤酒酵母胞外多糖发酵条件的研究

以啤酒酵母S－12为出发菌株,用紫外线＋氯化锂作为复合诱变剂,获得一株产胞外多糖量较高的变株S－12－4,比出发菌株提高33．3％,同时对变株进行了最佳培养条件的研究,结果表明：最适碳源和氮源分别为大米糖3％、酵母粉0．37％及NH4Cl0．32％,最适发酵条件为起始PH6．0、培养温度26℃,发酵周期为30h,在此基础上进行培养,变株S－12－4产胞外多糖最高可达38.2mg/100mL,比初始条件提高了54％。     

Genetic and fermentation properties of the K2 killer yeast, Saccharomyces cerevisiae T206

Saccharomyces cerevisiae T206 K⁺R⁺, a K₂ killer yeast, was differentiated from other NCYC killer strains of S. cerevisiae on the basis of CHEF-karyotyping and mycoviral RNA separations. Genomic DNA of strain T206 was resolved into 13 chromosome bands, ranging from approximately 0.2 to 2.2 Mb. The resident virus in strain T206 yielded L and M RNA species of approximately 5.1 kb and 2.0 kb, respectively. In micro-scale vinifications, strain T206 showed a lethal effect on a K^-R^- mesophilic wine yeast. Metabolite accumulation and toxin activity were measured over a narrow pH range of 3.2 to 3.5. Contrary to known fermentation trends, the challenged fermentations were neither stuck nor protracted although over 70% of the cell population was killed. Toxin-sensitive cells showed cytosolic efflux.