胸腺五肽纳滤浓缩过程研究

采用间歇浓缩方式,研究了纳滤对胸腺五肽离子交换洗脱液的浓缩特性。采用纳滤浓缩模型预测胸腺五肽离子交换洗脱液纳滤过程,系统考察透过通量和胸腺五肽浓度等随过程时间的变化。实验结果表明：截留相对分子质量为150的纳滤膜对胸腺五肽的截留率达到98．66％;胸腺五肽洗脱液透过通量随操作压力变化的结果表明,其纳滤过程为两机理控制;纳滤浓缩模型较好地模拟了胸腺五肽的纳滤浓缩过程,说明该模型适用于小分子多肽的纳滤浓缩过程。     

膜分离法纯化大蒜超氧化物歧化酶的条件研究

本文探讨了膜分离技术分离纯化大蒜超氧化物歧化酶(SOD )的工艺条件,研究了中空纤维超滤膜分离提纯大蒜SOD的工艺参数.通过单因素实验,分析了温度、压力、透过率对SOD活力回收率的影响;并通过正交实验确定出超滤膜分离法的最佳条件:温度32 ℃,压力0.15 MPa,透过率90%.在此基础上研究了纳滤膜对超滤液进行浓缩纯化的工艺条件,适宜的纳滤条件为:温度32 ℃,压力1.4 MPa.     

响应面法优化康定鼠尾草中迷迭香酸提取工艺

利用单因素实验和响应面法优化康定鼠尾草中迷迭香酸提取工艺。采用高效液相色谱法测定迷迭香酸含量,以提取率为参考指标。通过单因素实验筛选出料液比、提取时间和乙醇浓度三个主要因素,通过BoxBehnken设计方案,建立迷迭香酸提取得率的二次回归方程,得到优化组合条件。最佳提取条件为乙醇浓度40%,液固比15∶1,提取时间50 min。最佳提取条件下,迷迭香酸提取得率为12.30 mg/g。优化得到的康定鼠尾草中迷迭香酸的提取工艺合理,操作可行,质量稳定。     

膜技术提取玫瑰茄红色素工艺的初步研究

初步研究了用膜分离技术提取玫瑰茄红色素的工艺过程。选用微滤膜对浸提液进行精滤,再用纳滤膜浓缩滤液,确定微滤、纳滤膜的操作条件。研究表明,膜法提取玫瑰茄红色素是一种颇有前途的新技术。     

利用大孔树脂同时制备穿心莲内酯和脱水穿心莲内酯

采用大孔吸附树脂色谱法,以不同体积分数乙醇水溶液进行洗脱,分离富集穿心莲内酯和脱水穿心莲内酯,并配以HPLC进行同步监控.结果表明,穿心莲中这2种主要有效成分分别得到了富集.40%乙醇水溶液洗去目标物以外的杂质后,45%乙醇洗脱液中富含穿心莲内酯,含量为46.99%,55%乙醇洗脱液中富含脱水穿心莲内酯,含量为79.74%.     

苏云金芽孢杆菌增效物质回收工艺的改进

应用膜过滤技术对苏云金芽孢杆菌KN11增效物质回收工艺进行了改进,发现纳滤膜(200D)能完全截留KN11增效物质,通过3种膜过滤(0.1μm微滤膜、10000D超滤膜和200D纳滤膜)的总回收率达到85.5%;与常规回收比较,膜过滤回收工艺能显著提高浓缩液和粉的增效物质含量(分别为99.35U/mL,457.70U/g),同时除去了大部分的糖、氮等可溶性杂质,使浓缩液和粉保持了较好的理化性状。所配制的Bt高含量悬乳剂的效价在15645～19465IU/μL之间,含固量较低且流动性较好,Bt高含量原粉效价可达100646IU/mg。     

溶液中木质素和葡萄糖的超滤分离

以木质素和葡萄糖的混合溶液为木质纤维素水解液模型,采用截留相对分子质量为5 000的卷式聚醚砜膜对葡萄糖和木质素进行全回流模式的分离,探讨了木质素和葡萄糖浓度、操作压力、错流速率对通量、木质素和葡萄糖截留率的影响。结果表明:在实验条件范围内,通量随葡萄糖浓度和木质素浓度的增加而降低,并随操作压力、错流速率的增加而增加。木质素截留率不受任何条件的影响,基本稳定在97%。葡萄糖截留率随木质素浓度的增加而增加,并随错流速率的增加而减小。在0.8 g/L的木质素质量浓度条件下,当错流速率从0.12 m/s增加到0.17 m/s时,葡萄糖截留率从14%减小到7.3%。由此可见,在混合溶液的超滤过程中,通过合理选择错流速率,能够改善木质素和葡萄糖的分离。     

纳滤和吸附树脂法分离催化液中谷胱甘肽

采用纳滤和吸附树脂法从催化液中分离谷胱甘肽(GSH)。首先,考察两种不同分子截留量的纳滤膜分离和浓缩催化液中GSH的性能,其中DK1812(150～300)对GSH的截留率可达到97%以上,甘氨酸去除率达到90%以上;然后,从4种具有不同孔结构的吸附树脂中筛选出一种吸附容量大(40 mg/g)、选择性高(GSH与3种氨基酸之间的分离因子>2.0)的树脂HD-08,该树脂具有独特的微孔、中孔结构,其微孔结构有利于增强GSH的吸附容量,而中孔结构有利于其再生;最后,采用动态柱吸附-脱附的方法分离催化液中的谷胱甘肽,乙醇溶液梯度洗脱,洗脱液中GSH的HPLC纯度>98%、收率>95%、质量浓度>4.5 g/L。结果表明,采用膜分离和吸附法分离催化液中GSH,简单快捷,适用于大规模生产。     

大孔吸附树脂分离纯化人参二醇类和三醇类皂甙

本实验研究大孔吸附树脂从人参根提取物中富集、分离人参二醇类和人参三醇类皂甙的工艺条件及参数。用不同浓度的乙醇洗脱,使人参二醇类和三醇类皂甙实现富集分离,人参二醇类皂甙富集在80％乙醇洗脱液部分,人参三醇类皂甙富集在40％洗脱液部分。得到含量大于25％的人参三醇类皂甙,含量大于50％的人参二醇类皂甙,总皂甙洗脱率在91％以上。此法能够较好地分离、纯化人参二醇类和三醇类皂甙。     

大孔吸附树脂对红车轴草异黄酮吸附分离特性的研究

通过比较14种大孔吸附树脂对红车轴草异黄酮的吸附率和解吸率,筛选出适合红车轴草异黄酮分离的树脂,并对其动态吸附特性进行研究。结果表明,AB-8树脂对红车轴草异黄酮不仅吸附量大,而且解吸率高,适合红车轴草异黄酮的分离富集。AB-8树脂分离红车轴草异黄酮的工艺参数为:上柱液浓度0.79~1.11 mg/mL,pH 4.24,流速2 BV/h。以4倍树脂床体积的80%乙醇以2 BV/h流速进行洗脱,可基本上将红车轴草异黄酮从树脂上解吸下来,异黄酮回收率为93.72%。     

Recovery of lactic acid from fermentation broth by the two-stage process of nanofiltration and water-splitting electrodialysis

A two-stage process of nanofiltration and water-splitting electrodialysis was investigated for lactic acid recovery from fermentation broth. In this process, sodium lactate is isolated from fermentation broth in the first stage of nanofiltration by using an NTR-729HF membrane, and then is converted to lactic acid in the second stage by water-splitting electrodialysis. To determine the optimal operating conditions for nanofiltration, the effects of pressure, lactate concentration, pH and known added impurities were studied. Lactate rejection was less than 5%, magnesium rejection approximated 45%, and calcium rejection was at 40%. In subsequent water-splitting electrodialysis, both the sodium lactate conversion to lactic acid and sodium hydroxide recovery, were about 95%, with a power requirement of 0.9∼1.0 kWh per kg of lactate.     

紫锥菊单咖啡酰酒石酸和菊苣酸提取工艺优化

采用正交试验设计,选取乙醇体积浓度百分比、提取温度、提取时间、抗氧化剂用量等因素,优化紫锥菊Echinacea purpurea单咖啡酰酒石酸和菊苣酸的加热回流提取工艺,并考察加入抗氧化剂对提取效果的影响。结果表明,优化的提取条件是以25%乙醇,在80 ℃回流提取90 min。抗氧化剂用量对提取效果影响不显著。优化后的加热回流提取条件对紫锥菊单咖啡酰酒石酸和菊苣酸的提取均适用,提取中无需加入抗氧化剂。     

Sugar Syrup Concentration Using Reverse Osmosis Membranes

In sugar manufacturing industries, initially dilute syrup is obtained from the cane sugar or beetroot, which should be concentrated. In many factories, sugar syrup concentration is carried out using evaporation. This process has two main problems. Firstly, it consumes a huge amount of energy due to high latent heat of water and secondly, heating may decompose the sugar molecules resulting in low‐quality and dark‐colored sugar. Low energy consuming reverse osmosis may be employed for concentrating sugar syrup without decomposing the molecules, resulting in high‐quality sugar with low cost. In this study different commercial reverse osmosis membranes (DS, DSII, PVD, FT30, BW30) and one nanofiltration membrane (NF45) were used for sugar syrup concentration. The results show that nanofiltration NF45 membrane has no effect on sugar syrup concentration. The rejections of sugar using DSII and PVD reverse osmosis membranes vary between 23 % and 33 % for different operating conditions. DS membrane rejected around 10 % of the sugar molecules in best conditions. FT30 membrane initially showed better performance (55 %). However, the rejection was decreased during time (minimum 7 %). For BW30 membrane, the rejection of sugar was better (60 %) compared to the other membranes used in this work. For two‐stage processes (i.e. the permeate of the first stage used as a feed for the second stage) the highest rejection (88 %) was obtained.     

Concentration and desalting by membrane processes of a natural pigment produced by the marine diatom Haslea ostrearia Simonsen

The marine microalga Haslea ostrearia, also called blue navicula, presents the unique peculiar property among the diatoms, to produce at its extremities a blue hydrosoluble pigment called marennine. It is presented the concentration and the desalting of the exocellular pigment by membrane processes (ultrafiltration, nanofiltration, reverse osmosis). Nanofiltration is particularly developed given the potential of this type of application both for the concentration of molecules and for desalting. It is shown the effect of velocity and pressure on performances of nanofiltration membranes. Permeation flux superior to 100 l h⁻¹ m⁻² (at 14.10⁵ Pa) are obtained with the Kiryat Weizmann membrane MP 20 (polyester coated with a polyacrylonitrile layer, cut-off 450 Da). For the desalting of the blue pigment solution, nanofiltration membranes present a few advantages: a low salt rejection (less than 10% at 14.10⁵ Pa) and a high pigment rejection (the nanofiltration membrane MP 20 retains more than 95% of the pigment). This membrane used in diafiltration mode allows an acceptable speed of desalting (700 g of salt eliminated per hour and per m² at 25.10⁵ Pa for a concentration of 18 g of salt per litre of solution).     

Removal of potassium chloride by nanofiltration from ion-exchanged solution containing potassium clavulanate

In this study, nanofiltration with NF200 membrane was employed to remove KCl from ion-exchanged solutions containing potassium clavulanate. The pore radius of NF200 membrane was estimated to be around 0.39 nm. The effects of operating pressure on separation performance were investigated in a range of 100–400 psig. The influences of cross-flow velocity (0.14–0.70 cm/s), temperature (4–25 °C), and feed composition were also investigated. In all experiments, clavulanate rejection showed high levels from 0.91 to 0.99, while chloride rejection ranged from 0.06 to 0.54. In a case at an operating pressure of 50 psig and 25 °C, as much as 94% of clavulanate was retained while 94% of chloride was removed, indicating that NF200 membrane was a suitable choice for selectively removing KCl. NF200 membrane also showed a stable performance in the operational stability test with an ion-exchanged solution obtained by treating actual fermentation broth.     

A novel composite nanofiltration (NF) membrane prepared from graft copolymer of trimethylallyl ammonium chloride onto chitosan (GCTACC)/poly(acrylonitrile) (PAN) by epichlorohydrin cross-linking

A novel composite nanofiltration (NF) membrane was prepared by over-coating the PAN ultrafiltration (UF) membrane with a GCTACC thin layer. The effects of membrane preparation techniques and operating conditions on the performance of the composite membrane were studied. The results indicate that a composite NF membrane from 1.0wt% GCTACC casting solution, vaporized for 2h at 50 degrees C, cross-linked for 20h at 50 degrees C and pH approximately 12 with ethanol/epichlorohydrin (50/0.45 wt/wt) had optimum performance. The resultant GCTACC/PAN composite membrane was positively charged. Scanning electron microscopy showed its asymmetric and composite features. At 25 degrees C and 30L/h of cycling flow, the permeability of pure water through this membrane is 6.3L/hm(2)MPa. At 25 degrees C, 1.2MPa and 30L/h of cycling flow, the rejection of 1000mg/L MgCl(2), CaCl(2), MgSO(4), Na(2)SO(4), and NaCl solutions is 0.976, 0.972, 0.897, 0.65, and 0.407, respectively, with fluxes of 6.8, 6.12, 6.12, 5.57, and 5.51L/hm(2), respectively. The order of rejection of different salts follows the decreasing order of MgCl(2), CaCl(2), MgSO(4), NaCl, KCl, Na(2)SO(4), and K(2)SO(4), which reveals the characteristics of the positively charged NF membrane. In addition, the curve for the streaming potential also illustrates the positively charged characteristics of this membrane, with a pressure osmotic coefficient of 11.7mVMPa(-1).     

Separation and purification of benzylpenicillin produced by fermentation using coupled ultrafiltration and nanofiltration technologies

The purpose of this study was to evaluate the capacity of using coupled ultrafiltration-nanofiltration technologies for separation and purification of benzylpenicillin (BP). More specifically, we verified the efficiency of three ultrafiltration (UF) membranes (cut-off of 5000, 30,000 and 100,000 Da) to remove impurities that cause stable emulsion during the chemical extraction of the antibiotic. We also tested the effectiveness of a nanofiltration (NF) membrane (cut-off of 300 Da) to concentrate the benzylpenicillin recovered from permeates and to decrease the osmotic pressure by reducing the ionic charge of the broth. Results have shown that high recovery (89.0-91.0%) can be obtained in permeate generated by the 30,000 and 100,000 UF membranes, but a slight emulsion will be formed during phase separation. With the 5000 UF membrane, lower recovery is obtained (81.0%) but no emulsion is produced, leading to a high solvent extraction yield (94.6%). The nanofiltration of 30,000 and 100,000 UF permeates leads to very high recovery (98.0%), but stable emulsions are formed, reducing the chemical extraction yield (80.0-82.6%). For the nanofiltration of 5000 UF permeate, excellent recovery of the antibiotic is noted (97.4%) leading to high extraction yield (92.4%) with no emulsion formed. Diafiltration step should be applied during UF procedure in order to increase the antibiotic recovery in the generated permeates.     

Detoxification of hemicellulosic hydrolysates from extracted olive pomace by diananofiltration

Xylitol can be obtained from the pentose-rich hemicellulosic fraction of agricultural residues, such as extracted olive pomace, by fermentation. Dilute acid hydrolysis of lignocellulosic materials, produces the release of potential inhibitory compounds mainly furan derivatives, aliphatic acids, and phenolic compounds. In order to study the potential on the increase of the hydrolysate fermentability, detoxification experiments based on diananofiltration membrane separation processes were made. Two membranes, NF270 and NF90, were firstly evaluated using hydrolysate model solutions under total recirculation mode, to identify the best membrane for the detoxification. NF270 was chosen to be used in the diananofiltration experiment as it showed the lowest rejection for toxic compounds and highest permeate flux. Diananofiltration experiments, for hydrolysate model solutions and hydrolysate liquor, showed that nanofiltration is able to deplete inhibitory compounds and to obtain solutions with higher xylose content. Conversely to non-detoxified hydrolysates, nanofiltration detoxified hydrolysates enabled yeast growth and xylitol production by the yeast Debaryomyces hansenii, clearly pointing out that detoxification is an absolute requirement for extracted olive pomace dilute acid hydrolysate bioconversion.     

Activity and action pattern of Bacillus licheniformis alpha-amylase in aqueous ethanol

A purified B. licheniformis alpha-amylase in a mixture of ethanol-aqueous buffer (1:1, v/v) retains half the activity shown in water alone. In ethanol-aqueous buffer (7:3, v/v) about 20% of the activity is retained. The pattern of oligosaccharides produced from amylose changed with ethanol concentration; in aqueous buffer the products are: DP 1 and 2, 33.7%; DP 3, 28.5%; DP 4, 4.4% and DP 5, 33.4%. Whereas in ethanol-aqueous buffer (7:3, v/v) the products are DP 1 and 2, 66.8%; DP 3, 17.3%; DP 4, 4.1% and DP 5, 11.8%. These results suggest that a change in substrate affinity at the active centre subsites is induced in the ethanol-aqueous buffer medium.