聚丙烯酸甲酯载体对柱状假丝酵母脂肪酶固定化的研究（Ⅰ）

合成了一系列不同结构的聚丙烯酸甲酯，考察了它们的固定化酵母脂肪酶催化酯水解反应的效果，得到了载体孔结构对固定化效果影响的一些规律．研究了最佳吸附条件，比较ｐＨ和离子强度对酵母脂肪酶自由酶和固定化酶催化酯水解反应活力的影响．     

柱状假丝酵母脂肪酶同工酶的一种高效液相色谱分离新方法

建立一种“疏水界面亲和色谱”分离柱状假丝酵母脂肪酶同工酶的高效液相色谱新方法。将商品化的CRL经离子交换色谱分离为两个同工酶组分 (CRLA和CRLB) ,在极低离子强度下 ,根据同工酶活性中心周围处于“开放”构象的疏水腔具亲疏水界面的特性 ,用疏水界面亲和色谱在NucleosilC4 (10 μ ,3 0 0 ,2 5 0× 4.60mm)柱上将CRLA和CRLB都分离为 4种同工酶组分。疏水界面亲和色谱非常适用于分离这种结构差异轻微的同工酶组分     

南极假丝酵母脂肪酶B的催化机理及应用前景

脂肪酶[EC．3．1．1．3]由于具有活性高、专一性好、反应条件温和等优点已被广泛应用于油化学、清洁剂、食品工业和精细化工产品制备等很多领域．在众多脂肪酶中，CALB(Candidn antarctic lipase B，南极假丝酵母脂肪酶B)的用途最为广泛，它对非水溶性和水溶性物质都用很强的催化活性．近几年的研究成果表明，CALB以及Novozyme 435(吸附固定于大孔丙烯酸树脂的CALB)在酯化、     

聚甲基丙烯酸羟乙酯载体固定化酵母脂肪酸在有机溶剂中催化酯合成反应的研究

用悬浮聚合法合成了一系列聚甲基丙烯酸羟乙酯载体，考察了它们固定化酵母脂肪酶活力与载体的交联度和致孔剂用量之间的关系。研究了这些固定化酵母脂肪酶在有机溶剂中催化酯合成反应的活性。脂肪酶的固定化使之活力表达更为充分，对亲水性较强的有机溶剂有更强的耐受性，并能为其在有机溶剂中催化酯合成反应提供必需水。考察了ｐＨ值，底物种类对固定化酵母脂肪酶催化酯合成反应的影响。     

AOT/Triton X-100混合反胶束体系中假丝酵母脂肪酶催化蓖麻油水解的活性

研究了二(2-乙基己基)琥珀酸磺酸钠(AOT)/Triton X-100混合反胶束体系中假丝酵母脂肪酶(candida rugosa lipase)催化蓖麻油水解的反应. 考察了Triton X-100占总表面活性剂的摩尔分数(x(Triton X-100))、水与总体表面活性剂的摩尔比(ω0)、pH值、反应温度以及底物蓖麻油的浓度等因素对酶活性的影响. 研究结果表明, 加入非离子表面活性剂Triton X-100可以使假丝酵母脂肪酶的活性得到显著提高, 但是当底物蓖麻油的浓度大于0.24 mol·L-1时, 会对假丝酵母脂肪酶产生抑制作用.     

近平滑假丝酵母细胞催化乙酰基三甲基硅烷不对称还原反应

 采用近平滑假丝酵母细胞用于催化乙酰基三甲基硅烷不对称还原反应, 可高选择性地生成 (R)-1-三甲基硅乙醇. 结果表明, 固定化于海藻酸钙的细胞催化该反应的产物收率比游离细胞的高. 不同辅底物对该反应的影响显著, 以葡萄糖为辅底物时, 反应的初速率较快, 产物收率较高. 该反应的最适条件为: 辅底物 (葡萄糖) 浓度 110 mmol/L, 振荡速度 180 r/min, 缓冲液 pH 值 6.0, 反应温度 30 oC, 底物浓度 20 mmol/L. 在此反应条件下反应的初速率、产物收率和产物的 ee 值分别为 11.4 μmol/h, 96.5% 和 99.9%.     

钯杂多酸/SBA-15的合成及正十六烷的催化氧化

将钯杂多酸锚定在3-氨丙基-三乙氧基硅烷(APTS)修饰的SBA-15孔道内, 得到了一种新型、高效的钯杂多酸/SBA-15 (Pd₃Bi₂W₂₂/SBA-15)多相催化材料. 采用XRD和FT-IR红外光谱对催化剂进行了表征, 并检测了其对正十六烷氧化的催化性能. 结果表明, 以空气为氧化剂, 在无任何溶剂的条件下, 该催化剂对正十六烷烃氧化成醇类和酮类显示出了优良的催化性能, 并且可多次回收利用.     

高压CO2条件下粗状假丝酵母催化苯乙酮不对称还原合成α-苯乙醇

 研究了在高压CO2条件下利用粗状假丝酵母Candida valida CICC1444活性细胞催化苯乙酮不对称还原合成(R)-α-苯乙醇. 高压CO2条件可对粗状假丝酵母细胞的活性产生一定的影响,但反应的选择性反而有所提高,证实了高压CO2作为该反应环境是可行的. 考察了底物浓度、细胞用量、反应温度和压力等因素对反应的影响. 结果表明,这些因素对反应产率有很大的影响,在最佳反应条件下,反应底物苯乙酮的转化率和产物α-苯乙醇的产率均可达90%以上,对映体过量值(ee)保持在80%左右. 与常压静置条件下的反应相比,高压CO2条件下粗状假丝酵母催化苯乙酮不对称还原反应的转化率和产率分别提高了20%和40%左右,对映体选择性也提高了5%～10%.     

硒酵母中硒含量测定方法的研究

报道了人工培养硒酵母中总硒、无机硒和有机硒的测定方法,建立了无机硒和有机硒的鉴别方法,并采用透析处理法使硒酵母中的无机硒和有机硒得以分离;还报道了不同培养条件下得到的5种硒酵母中总硒、无机硒和有机硒的定量分析数据,为硒酵母在医药和添加剂领域的应用提供了可靠的数据。     

盐碱法提取酵母核酸的工艺研究

对盐碱法提取酵母核酸进行了研究。结果表明,最佳提取条件为提取温度85℃,提取pH为7.5,NaCl的含量为6.5%,提取时间180 min,对酵母核酸的平均提取率达到5.70%。     

Simultaneous Determination of Epinephrine and Dopamine by Using Candida tropicalis Yeast Cells Immobilized in a Carbon Paste Electrode Modified with Single Wall Carbon Nanotube

A new electrochemical microbial biosensor system based on Candida tropicalis was developed for the fast detecting of dopamine and epinephrine. Candida tropicalis was immobilized in a carbon paste electrode (CPE) with single wall carbon nanotube (SWCNT). Immobilized cells were used as a origin of the polyphenol oxidase (PPO) to develop voltammetric epinephrine and dopamine biosensor. Voltammetric determination of phenolic compounds such as epinephrine and dopamine a simple technique which is available. Direct oxidation of phenols can be used, but the oxidation potentials of this compounds are similar and they can not be detected distinctively. Another possibility is the use of biosensors based on the polyphenol oxidase (tyrosinase) enzyme that oxidizes the phenolic compounds into their related quinones. By this way, phenolic compounds are epinephrine and dopamine which were used in this study as well detected at different potentials. In this study differential pulse voltammetry and amperometry techniques were used for the determination of dopamine and epinephrine. The effect of varying the amounts of SWCNT and the response of microorganism to epinephrine was investigated to find the optimum composition of the sensor. The effects of pH and temperature were also examined. Increases in biosensor responses obtained by amperometric measurements were linearly related to dopamine concentrations between 0.025 and 0.25 mM and epinephrine concentrations between 0.01 and 0.1 mM. Limits of detection of the biosensor for dopamine and epinephrine were calculated to be 0.008 and 0.0023 mM, respectively. Finally, proposed system was applied to epinephrine and dopamine analysis in pharmaceutical drugs and synthetic serum and the results were compared with LC MS MS method.     

Yeast Strains and Wort Color as Factors Affecting Effects of the Ethanol Fermentation Process

Dark malts used in the production of brewing wort affect the ethanol fermentation process, the phenolic content, antioxidant capacity and the physiology of yeast cells. An innovative element of this research is the combination of investigating the effect of beer wort color modulated by the use of dark specialty malts on the course and effects of fermentation and the characteristics of post-fermentation yeast biomass of brewer’s strains with different characteristics. Dark and pale beer were obtained. The beers had different ethanol contents (4.51–5.79% v/v), resulting from real (62.29–80.36%) and apparent (75.37–98.26%) attenuation levels. Metabolic and morphological differences were demonstrated in the brewer’s yeast strains used. S. cerevisiae var. diastaticus was distinguished by its ability to ferment dextrin, resulting in the highest ethanol content in beers. The total phenolic content in beer depends on the color of the wort and the yeast strain used (244.48–547.56 mg of gallic acid/L). Dark beers show higher ferric ion reduction ability (FRAP) and antioxidant capacity (ABTS^•+) than pale beers fermented with the same yeast strains. Through biomass analysis, differences in yeast cell physiology depending on yeast strain and beer wort color were also revealed.     

富硒酵母的研究开发与应用

介绍了硒的生理功能、人体对硒的需求、富硒酵母的开发以及作为功能性食品基料在各方面的应用。     

富铬酵母中铬的化学种态及结合形态研究

对富铬酵母中铬的化学种态进行了分析和初步探讨。在铬的化学种态测定中铬的使用离子交换和火焰原子吸收法测定了富铬酵母中的Ｃｒ（Ⅲ）,方法快速简便、定量回收,结果表明,总铬呈为１５８２μｇ／ｇ的富铬酵母中,无机态铬占１６％,其中Ｃｒ（Ⅲ）为２３２μｇ／ｇ,Ｃｒ（Ⅵ）为２４．５μｇ／ｇ。酵各过程中的８４％以上的无机铬化合物转化成有机铬。说明铬参与了酵母细胞的生物合成,促进生物转化,对提高富铬酵母的生物疚极     

Studies on the Physical Properties of Alkanes Using Edge-adjacency Information Topological Index

Edge-adjacency index and information topological index for 82 molecules of alkanes nave been constructed and calculated. The topological indices were used to correlate with seven physical properties of the alkanes. Some empirical equations were obtained through regression. The regression and calculation results show a good agreement of the topological indices and the properties.     

Studies on the overproduction of indole-containing metabolites by a methanol-utilizing yeast

Production of indole-containing metabolites (“indoles”) from methanol has been studied using a mutant ofHansenula polymorpha resistant to 5-fluorotryptophan. Whereas the wild-type culture produces only a small amount of indoles, the mutant is partially deregulated and overproduces indoles. Indoles production was studied in batch and continuous culture and in a washed-cell system. When the pH was above 4.0, indoles production was growth-associated, in both minimal and complex media, and batch or continuous culture. When the pH was below or equal to 4.0, a low phosphate concentration was found to improve production. In a phosphate-deficient washed-cell suspension system, the addition of an amino acid such as methionine at 5 mM increased specific productivity by more than 60%. Addition of cycloheximide at 50 mg/L decreased residual growth and increased maximum productivity of indoles by more than 60%. When the antibiotic was added at 1000 mg/L, growth was completely inhibited and indoles production continued for about 35 h.     

Bioemulsifier production in batch culture using glucose as carbon source by Candida lipolytica

The yeast Candida lipolytica IA 1055 produced an inducible extracellular emulsification activity while utilizing glucose at different concentrations as carbon source during batch fermentation at 27°C. In all glucose concentrations studied, maximum production of emulsification activity was detected in the stationary phase of growth, after pH reached minimal values. The bioemulsifier isolated was a complex biopolymer constituting proteins, carbohydrates, and lipids. The results obtained in this work show that the biosynthesis of a bioemulsifier is not simply a prerequisite for the degradation of extracellular hydrocarbon.     

酵母细胞为模板矿化合成SiO2纳米结构材料的研究

根据无机盐可以在生物细胞膜上沉积形成纳米结构材料的现象和生物矿化理论, 在人工培养条件下, 成功地以低等真核生物细胞-酵母菌为模板, 以正硅酸乙酯(TEOS)作为硅源, 矿化合成了一种壳鞘状的SiO2纳米结构材料, 厚度达150 nm左右, 并采用TEM、SEM、EDX、FT-IR、TGA等表征手段对实验结果进行了深入细致的研究, 获得了大量的实验数据, 为利用生物细胞模板合成介观尺寸有序SiO2纳米材料作出了有益的尝试.     

中子活化法研究富铬酵母中铬的含量和分布

利用中子活化法测定了富铬酵母细胞中的生物活性物质、细胞壁以及原隆质体中的铬的含量。铬通过细胞壁进入细胞后,８０％的铬存在于细胞的原生质体内;富铬酵母中的铬主要以生物活性物质的形式存在。表明无机铬化合物在富铬酵母细胞的培养过程中,被酵母细胞吸收,并转化成有机铬状态。