微型法制备和提纯乙酰苯胺

有机实验教材中,常采用苯胺和冰乙酸加热回流、分馏分水法制备乙酰苯胺,并用热过滤和重结晶法将其提纯。该法在具体实践中,暴露出操作复杂、时间长,产率低等缺点。因此从实验微型化入手,选取合适的酰化试剂,在不加热的情况下,制备和提纯乙酰苯胺。并解决了常温过滤过程中的堵塞、污染问题,减少了副产物的产生。     

湿法磷酸净化除铁的现状

以净化湿法磷酸代替热法磷酸生产磷酸盐已成为近代发展趋势。为了扩大湿法磷酸的应用领域必须净化湿法磷酸中的杂质。从湿法磷酸中分离铁,已经开发了沉淀法、离子交换法、吸附法、溶剂萃取法、膜分离法等方法,各有利弊。     

菊芋的贮藏与果聚糖提取研究

对菊芋块茎贮藏条件、果聚糖的提取与提取液的精制进行了研究.结果:收获后的菊芋块茎在室温存放时间不宜超过10 d,在5℃条件下存放不宜超过20d,将菊芋块茎清洗后装入聚乙烯袋中,置于1℃的条件下存放能长期贮存;以水为提取剂,提取果聚糖的工艺条件为:水:料为3:1,水温为100℃,时间为20min,次数为3,果聚糖的得率较高;用Ca(OH)2将提取汁的pH值调到11,然后用H2PO4将其pH值调回到8的澄清效果最好;通过离子交换树脂处理后能获得色泽、风味较好的提取汁.     

嗜热芽孢杆菌HSO8耐热中性蛋白酶的分离纯化及部分特性研究

从高温土壤中分离出1株产耐热中性蛋白酶的嗜热芽孢杆菌,研究了该酶的分离纯化与生化特性.蛋白酶经硫酸铵沉淀、DEAE-Sepharose离子交换层析和Sephacryl S-100HR凝胶层析分离纯化后,纯化倍数提高4.25倍,产率5.1%;经SDS-PAGE电泳测得其分子质量为30.9 kDa.酶的最适温度与pH试验表明,其最适温度为65 ℃,最适pH为7.5,并在50 ℃时保持1 h以上的稳定.该蛋白酶活性受到EDTA的抑制,Zn2+能提高酶活性,该酶为金属蛋白酶.改性酪蛋白(Azocasein)、酪蛋白、牛血清白蛋白(BSA)等3种底物专一性试验表明,改性酪蛋白是其最适底物.     

Nisin的生产、提纯和检测

Nisin是一种由乳酸乳球菌产生的羊毛硫氨酸类细菌素 ,在许多国家被许可作为生物防腐剂。Nisin的产量受许多因素的制约 ,如产生菌性能、培养基组成 (碳源、氮源、磷源和阳离子 )、发酵条件 (pH、温度、搅拌、通风 )、发酵类型 (分批发酵、连续发酵、自由细胞、固定化细胞 )等 ;大规模回收和纯化Nisin主要采用一些基于吸附-解析或者相分配原理的方法 ;最常用的定量检测Nisin的方法主要有生物分析法和免疫检测法 ,采用各种特定nisin抗体的免疫检测方法具有迅速、灵敏、准确等特性并能实现Nisin的在线检测。     

Low molecular weight serine protease from the viscera of sardinelle (Sardinella aurita) with collagenolytic activity: Purification and characterisation

A new low molecular weight (LMW) serine-protease from sardinelle (Sardinella aurita) viscera was purified using ammonium sulphate precipitation and Sephadex G-100 gel filtration, with a 3.82-fold increase in specific activity. The molecular weight of the enzyme was estimated to be 14.2 kDa by SDS-PAGE. The optimum pH and temperature for the enzyme activity were around pH 8.0 and 60 °C, respectively. The purified protease was strongly inhibited by phenylmethylsulphonyl fluoride, a serine-protease inhibitor, and soybean trypsin inhibitor. The N-terminal amino acid sequence of the first 10 amino acids of the purified protease was APVQPCVVVI. This sequence showed low homology with several peptidases, suggesting that the enzyme is a new protease. Interestingly, the protease was found to cleave collagen type I and hydrolyze succinyl-L-Ala-L-Ala-L-Pro-L-Phe-p-nitroanilide (sAAPFpna), an amide substrate of chymotrypsin. Our findings indicate that the S. aurita protease is a new LMW enzyme with collagenolytic activity.     

Process integration for hydrogen production,purification and storage using iron oxides

Hydrogen production from natural gas using a Ni-based catalyst and its later hydrogen storage with some synthetic and natural iron oxides are presented. The Ni-based catalyst showed high methane conversion, close to the equilibrium one, when producing hydrogen from methane through catalytic partial oxidation (CPO) and wet-CPO with a low steam to carbon ratio (0.5). The solid solution formation observed in the Ni-based catalyst could have enhanced its stability. The iron oxides capacity for hydrogen storage was analysed with reduction–oxidation cycles at 973 K and atmospheric pressure. The natural oxides presented structural modifications, mainly due to sinterization, which negatively affected their storage capacity and stability.     

添加氧化剂对干电池电液净化的功能分析

通过配电液发生的水解现象分析，导出了添加氧化剂后，可使有害的２ 价铁离子浓度迅速下降，从而有利于电液的净化。     

Purification of biodiesel from used cooking oils

In Europe, methyl esters cannot be classified as biodiesel until the EN 14214 Standard specifications are fulfilled. The aim of this paper is to examine the efficiency of removing several impurities in biodiesel from used cooking oils by means of three basic operations under conditions that have been kept as close to commercial operating practice as possible: (a) adsorption (magnesium silicate and bentonite); (b) liquid–liquid extraction (distilled water, tap water, glycerol); and (c) ion exchange (cation resin). The results show that all the purification methods can remove soap, methanol and glycerol effectively, while none had an effect on density, kinematic viscosity, FAME content or glyceride content. However, some of them have shown an influence on FFA and water content. The liquid–liquid extraction with glycerol at 15 wt.% and a 2-step contact proved to be the most suitable.     

Automated Microscale His‐tagged Protein Purification Using Ni‐NTA Magnetic Agarose Beads

To achieve standardized and parallelized microscale protein purification, an automated purification system was developed and optimized using a pipetting robot for purifying large sets of proteins with Ni‐NTA magnetic agarose beads. Recombinant hexahistidine‐tagged proteins β‐glucanase (Bgl‐His) and esterase I of Pseudomonas fluorescens (PFE I) were tested on the system. High purity along with high coherence was achieved. The purification procedure can be applied to 96 samples simultaneously and only takes about 1/3 of the time required for purification conducted by hand. Due to the stability of the robot system, the consistency of the results is much better than the results achieved through manual purification. This rapid and reliable method is reproducible and applicable to high throughput screening of huge amounts of samples.