枯草芽孢杆菌Dg5041液体发酵生产γ-聚谷氨酸

以枯草芽孢杆菌Dg5041为生产菌,对其摇瓶发酵生产γ–聚谷氨酸(γ-PGA)的工艺进行研究,通过单因素实验和正交实验获得了该菌的优化培养条件。优化的培养基组成为:葡萄糖35 g/L,酵母膏10 g/L,谷氨酸钠40 g/L,MgSO41.0 g/L,K2HPO4 2.0 g/L,MnSO40.5 g/L,pH 7.0,250 mL锥形瓶装液量50 mL。菌种在37℃,120 r/min培养24 h加入5%NaCl后继续培养24 h,γ-PGA产量达到18.54 g/L。研究结果表明,枯草芽孢杆菌Dg5041是一株很有潜力的γ-PGA高产菌。     

γ-叔丁基过氧丙基三甲氧基硅烷的制备及表征

以过氧化氢叔丁醇和3-氯丙基三甲氧基硅烷为原料,以三氯化铁为催化剂在甲苯溶剂中首次了合成γ-叔丁基过氧丙基三甲氧基硅烷。利用红外吸收光谱、¹H核磁共振谱以及质谱对产物表征,确定其结构。通过研究催化剂种类、反应物配比、反应时间以及反应温度等因素对合成反应的影响,探讨出实验最佳方案为:反应时间8h,反应温度40℃,n(过氧化氢叔丁醇):n(3-氯丙基三甲氧基硅烷)=1.2:1,催化剂用量为3-氯丙基三甲氧基硅烷质量的1.5%。在此条件下,产物产率最高为42%。     

γ-射线液位计在尿素装置中的应用探讨

介绍了γ-射线液位计的测量原理及在云南云天化股份有限公司尿素装置中的应用现状、常见故障及处理方法、维护注意事项。     

对-烷基-苄基聚氧乙烯醚羧酸甜菜碱的合成与表面活性

以脂肪酸、苯、二缩三乙二醇为原料,经酰化反应、黄鸣龙还原反应、氯甲基化反应、威廉逊成醚反应、卤化反应、季铵化反应,合成出了3个对烷基苄基聚氧乙烯醚羧酸甜菜碱两性离子表面活性剂。用IR、1HNMR和ESI-MS对产物进行了结构鉴定。用Wilhelmy-plate法测定了30℃时它们在水溶液中的临界胶束浓度(CMC)和临界胶束浓度下的表面张力(γCMC)。实验表明,纯水溶液中表面活性剂的临界胶束浓度(CMC)为10-4～10-6mol/L,临界胶束浓度下的表面张力(γCMC)为27～30 mN/m;随着苯环上长链烷基碳数(n=8、10、12)的增加,CMC分别为1.12×10-4、1.51×10-5、6.21×10-6 mol/L;γCMC分别为27.9、28.4、29.9 mN/m。结果表明,该类表面活性剂具有比较好的表面活性。     

γ-Oryzanol Recovery from Rice Bran Oil Soapstock

The suitable conditions were determined for the recovery of high-value antioxidative compound, γ-oryzanol, from low cost rice bran soapstock by-product of the rice bran oil industry. First, soapstock was saponified and was then dehydrated and extracted with ethyl acetate. The extract was further purified by crystallization twice in appropriate solvent systems. At the most suitable conditions, using 20% v/v of ethyl acetate in methanol, and at 30°C and 1 h for the first crystallization step, and 5°C and 24 h for the second, the yield and purity of γ-oryzanol were 55.17 ± 0.59 wt% and 74.60 ± 4.12 wt%, respectively.     

以L-谷氨酰胺-锌(II)配合物为供体酶法制备茶氨酸及其反应机理

针对酶法合成茶氨酸中存在的自转肽副反应,合成了L-谷氨酰胺-锌(II)配合物Zn(Gln)2,以其为供体、乙胺为受体、枯草芽孢杆菌B. subtilis GGT为催化剂,酶法制备茶氨酸. 结果表明,Zn(Gln)2在反应主体相稳定性良好,以Zn(Gln)2为供体可有效抑制自转肽副反应;B. subtilis GGT对Zn(Gln)2和Gln的亲和力常数分别为0.53 mmol/L和1.01 mmol/L. 在Zn(Gln)2 6.0 mmol/L、乙胺200 mmol/L及GGT 0.5 U/mL条件下,经37℃反应2 h,茶氨酸浓度最高可达7.38 mmol/L,较以Gln为供体时提高了14.42%.     

γ-Al2O3表面结构的红外光谱研究

采用原位红外光谱技术对不同温度(100～500℃)脱水γ-Al2O3的表面羟基进行了研究,同时应用吡啶吸附原位红外光谱法对γ-Al2O3表面上路易斯酸(L酸)进行了研究.实验结果表明,在升高脱水温度的过程中,在γ-Al2O3表面共出现五个羟基谱带,分别为3785,3762,3725,3697,3674 cm-1.在γ-Al2O3表面上存在三种L酸性位,分别对应于五配位(酸性最弱)、四配位(酸性中等)和三配位的Al3+(酸性最强).这三种Al3+的数量随脱水温度升高而增大,而且γ-Al2O3表面上的L酸性位均有羟基与其相连.     

γ-(2,3环氧丙氧)丙基三甲氧基硅烷改性壳聚糖渗透蒸发杂化膜的制备及乙醇脱水性能研究

通过γ-缩水甘油醚氧丙基三甲氧基硅(KH-560)对壳聚糖进行交联改性制备乙醇脱水渗透蒸发杂化膜.实验结果表明偶联剂的加入能有效提高壳聚糖膜的分离效果,随着偶联剂含量的增加,杂化膜的对水的选择性先增加后下降,在2％(质量分数)时有最好的选择性.膜的分离因子随着进料温度的增大而降低,随着乙醇浓度的增大而增大;通量随着进料温度的增大而增大,随着乙醇浓度增大而减小.硅烷偶联剂/壳聚糖杂化膜呈现出良好的渗透蒸发分离性能,当进料乙醇浓度为95％(质量分数),温度为35℃时,通量和分离因子分别为134g/(h·m2)和97214.     

Synthesis and functionalization of nanoengineered materials using click chemistry

The synthesis of nanoengineered materials with precise control over material composition, architecture and functionality is integral to advances in diverse fields, including biomedicine. Over the last 10 years, click chemistry has emerged as a prominent and versatile approach to engineer materials with specific properties. Herein, we highlight the application of click chemistry for the synthesis of nanoengineered materials, ranging from ultrathin films to delivery systems such as polymersomes, dendrimers and capsules. In addition, we discuss the use of click chemistry for functionalizing such materials, focusing on modifications aimed at biomedical applications.     

Synthesis and process modeling of mesoporous γ-Al2O3 granules using the biopolymer chitosan via experimental design

In this study, biopolymer chitosan is presented as a template for synthesizing and shaping the mesoporous γ-Al₂O₃ macrospheres. This porous γ-Al₂O₃ granule has a high surface area (310 m²/g), high pore volume (.6148 cm³/g), and pore diameter between 2 and 10 nm. The full factorial design based on a mathematical model was implemented to study the acid concentration, chitosan amount, ammonia concentration, and aging time affecting the responses (Brunauer–Emmett–Teller surface area and pore volume). Predicted responses were found to be in satisfactory agreement with experimental values (R² = .9580 and .9109, respectively). The adequacy of the model was examined by analyzing the residual distribution plots and Pareto graph. X-ray diffraction, scanning electron microscopy (SEM), thermogravimetric analysis, and N₂ adsorption/desorption techniques are employed to characterize the structure of the prepared γ-alumina sample.