Immobilization of amyloglucosidase on polystyrene anion exchange resin I. preparation and properties

Amyloglucosidase (exo‐1,4‐ α‐D‐glucosidase, E C 3.2. 1.3) was coupled to glutaraldehyde activated Indion 48‐R (a cross‐linked macroporous anion exchanger) by Schiff base reaction. The bound enzyme exhibited 60–70% activity of the free enzyme. Substrate concentrations as high as 32% (w/w) liquefied tapioca starch could be quantitatively converted into 96–98% (w/w) dextrose in 24 h at 50°C and pH 4.5. Though immobilization lowered the temperature optimum to 50–60°C from 65°C for the free enzyme, it increased the temperature stability. However, there was no change either in the pH optimum or pH stability after immobilization. In batch operations, the immobilized preparation showed a half life of 32 and 12 days at 50°C and 60°C respectively.     

改性壳聚糖为载体制备喹乙醇分子印迹聚合物及其表征

以交联化壳聚糖微球为表面载体,水和乙腈为混合溶剂,将模板分子（喹乙醇）,功能单体（丙烯酰胺）及交联剂（N,N’-亚甲基双丙烯酰胺）采用表面分子印迹与溶胶-凝胶法合成喹乙醇分子印迹聚合物（MIP）。并对新型水相分子印迹聚合进行红外光谱、扫描电镜、吸附动力学实验、吸附平衡实验、选择性实验的表征。实验结果表明:以壳聚糖为载体的分子印迹聚合物对喹乙醇的吸附容量为10.14mg·g-1,对喹烯酮的印迹效率因子为2.29,乙酰甲喹的印迹效率因子为2.22。以壳聚糖为载体的分子印迹聚合物具有较高识别选择能力,对喹乙醇具有快速吸附效果。      

基于聚合物微球接枝硅油的超滑棉织物制备及其防污性能

为提高超滑织物的物理化学稳定性,首先采用乳液聚合法以乙烯基改性纳米二氧化硅(V-SiO₂)为原料制备自黏性核壳型聚合物微球,将其经浸涂-焙烘工艺组装到棉织物表面得到粗糙基底;然后利用氨基-环氧基接枝反应、氨基-羟基氢键作用将氨基硅油接枝在粗糙基底表面得到超滑织物。探究了超滑织物的疏液、防污及物理化学稳定性能。结果表明：超滑织物中超滑表面的粗糙结构由粒径为321.3 nm的微球构成,表面水滴接触角为138°;水、二甲基亚砜在超滑织物表面的滑动角分别为7°、15°;接触番茄酱、咖啡污物后,超滑表面黏附量显著减少;经200 mL以内水冲击后,超滑织物表面水、二甲基亚砜的滑动角分别小于12°、26°;在pH值为3～9条件下其表面液滴的接触角稳定在42°～49°之间。     

猪皮不溶性胶原的特性研究

探讨了猪皮不溶性胶原的可溶化率和可溶化物的结构,分别比较了猪皮和牛皮两种试样。由于动物的年龄不同,胶原的性质变化显著,不溶性胶原在pH7.5、60℃水中加热时,4个月龄猪皮和幼牛皮在1h可溶化60%,22h可溶化90%,但1年龄猪皮和成牛皮可溶化率减少30%⁴0%。用20℃2mol/L氯化钙或45℃1mol/L尿素使其溶化时的可溶化率也有类似的现象。不溶性胶原用胃蛋白酶处理后,由于动物年龄差异引起的可溶化率差别明显减小,猪皮80%以上,牛皮60%以上可溶化。这种可溶化物的SepHarosecl-4B凝胶过滤图谱与胃蛋白酶未处理区比较,显示α成分的比例显著增加,而且猪皮的这种变化较牛皮更大。      

非织造布增强复合材料的制备与力学分析

分别采用手糊法、真空袋法和真空辅助成型法制备了非织造布增强不饱和聚酯树脂复合材料 ;宏观上对这三种复合材料的拉伸、弯曲、冲击等力学性能进行了测试 ,并加以比较 ;微观上利用电镜扫描图分析了复合材料的破坏形式和机理。     

一种新型纤维素基吸附剂的制备及其对漆酶的固定化性能研究

利用NaOH/尿素体系溶解纤维素并加入纳米碳酸钙,而后在盐酸溶液中再生,制得具备多孔结构的纤维素小球;之后采用丙烯酰胺对纤维素小球的羟基进行改性,接枝碳链并引入酰胺基,在碱性条件下酰胺基水解为羧基,得到改性纤维素基吸附剂;其可通过静电吸附和氢键间作用力固定漆酶。对接枝改性和漆酶固定化的最佳条件进行了探索,得到最佳改性条件为：时间6 h、温度50℃、单体配比8∶5、引发剂浓度0.08%;最佳固定化条件为：pH值=5.0、初始酶浓度10 g/L、固定化时间3 h。利用此最佳改性纤维素小球在最佳条件下固定的漆酶具有良好的热稳定性和可重复使用性,酶活提高了52%。结果表明,改性纤维素小球作为一种新型的绿色载体,在漆酶固定化方面具有广阔的应用前景。     

甘蔗块固定化酵母的制备及其在蔗汁燃料乙醇生产中的应用

以甘蔗块为载体固定酵母细胞,通过优化载体大小和预处理方式,制备得到性能优良的固定化酵母,应用于蔗汁燃料乙醇的生产。研究结果表明,大量酵母细胞固定于甘蔗块内部空腔以及吸附于甘蔗块表面;较小的甘蔗茎块作为固定化载体,乙醇产率增加10%左右;冷冻储存的甘蔗块经过解冻、去木质素处理后固定酵母,以40%的装填率发酵36 h,乙醇浓度达99.34 g/L,糖利用率为99.23%,发酵效率为93.09%。     

脂肪酶在磁性纳米粒子上固定化及其酶学性质研究

以Fe_3O_4纳米粒子为载体,碳化二亚胺为交联剂,共价结合制备固定化脂肪酶,探讨脂肪酶固定化影响因素,并对固定化脂肪酶性质进行研究;运用TEM测定其粒径,用FTIR检测脂肪酶—Fe_3O_4磁性纳米粒子耦联。结果表明,脂肪酶固定化适宜条件为:200 mg磁性纳米粒子,加入2 ml 2.5mg/mL脂肪酶磷酸盐缓冲液(0.1mol/L,pH7.5),在4℃超声分散45 min,固定化酶最适pH为7.0,最适温度为45℃,均与游离酶相似;与游离酶相比,该固定化脂肪酶热稳定性明显提高,并具有良好操作和存储稳定性。     

Effects of micronisation on the characteristics and physicochemical properties of insoluble fibres

The effects of micronisation on the characteristics and physicochemical properties of (a) an insoluble fibre‐rich fraction (IFRF) prepared from orange peel and (b) cellulose were studied and compared. The results showed that micronisation techniques such as ball milling, jet milling and high‐pressure micronisation could effectively (P < 0.05) reduce particle sizes to microscale, decrease the bulk density and improve the physicochemical properties (water‐holding capacity, swelling capacity, oil‐holding capacity, cation exchange capacity and glucose adsorption capacity) of IFRF and cellulose to different extents (up to 25‐fold). After micronisation the inhibitory effects of these insoluble fibres towards α‐amylase and pancreatic lipase were significantly increased (up to 5.8‐ and 7.8‐fold respectively) and a redistribution of some fibre components from insoluble to soluble fractions was observed. It was concluded that these micronisation treatments, especially high‐pressure micronisation, could effectively improve the functionalities of IFRF and cellulose, which might then be used as potential fibre‐rich ingredients in functional food applications. Copyright © 2006 Society of Chemical Industry     

Immobilization of peroxidase on textile carrier materials and their application in the bleaching of colored whey

Textiles represent promising support materials for enzymes. The goal of the present work was to investigate the immobilization of commercial peroxidase on a polyester needle felt and the repeated use in the gentle degradation of norbixin in whey from dairy cheese as a practical application. High enzyme loads were obtained by a 2-step immobilization procedure. First, the number of functional groups on the textile surface was increased by a modification with amino-functional polyvinylamine. Second, the enzyme was immobilized by using 2 types of crosslinking agents. Due to the iron content of peroxidase, inductively coupled plasma–optical emission spectrometry was used for the quantitative determination of the enzyme load on the textile. The enzyme activity was evaluated using common 2,2'-azino-di-(3-ethylbenzthiazoline-6-sulfonic acid) assay for peroxidases. By the variation of enzyme input and crosslinker concentration, a maximal enzyme load of 80 mg/g of textile was achieved, and a maximum specific activity of 57 U/g of textile. For the visualization of the enzyme on the fiber surface, fluorescence microscopy as well as scanning probe microscopy were used. The immobilized peroxidase showed significant activity, even after 50 reuse cycles. In addition, the potential of the new support and enzyme combination in commercial whey bleaching was demonstrated successfully on a 10-L scale.     

Effect of insoluble calcium concentration on rennet coagulation properties of milk

Rennet-induced gels were made from milk acidified to various pH values or milk at pH 6.0 that had added EDTA. The objective was to examine the effect of removing insoluble Ca (INS Ca) from casein micelles (CM) on rennet gelation properties. For the pH trial, diluted lactic acid was added to reconstituted skim milk to decrease the pH to 6.4, 6.0, 5.8, 5.6, and 5.4. For the EDTA trial, EDTA was slowly added (0, 2, 4, and 6 mM) to reconstituted skim milk, and the final pH values were subsequently adjusted to pH 6.0. Dynamic low amplitude oscillatory rheology was used to monitor gel development. The Ca content of CM and rennet wheys made from these milks was measured using inductively coupled plasma spectroscopy. The INS Ca content of milk was altered by the acidification pH values or level of EDTA added. In all samples, the storage modulus (G′) exhibited a maximum (GM), with a decrease in G′ during longer aging times. Gels made at pH 6.4 had higher GM compared with gels made at pH 6.7 probably due to the reduction in electrostatic repulsion, whereas the INS Ca content only slightly decreased. The highest GM value of gels was observed at pH 6.4 and the GM value decreased with decreasing pH from 6.4 to 5.4. This was due to an excessive loss of INS Ca from CM. There was a decrease in GM with the increase in the concentration of added EDTA, which was probably due to the loss of colloidal calcium phosphate, which weakens the integrity of CM. Loss tangent (LT) values at GM increased with a reduction in milk pH and the addition of EDTA to milk. Rennet gels at the point of the GM were subjected to constant low shearing to fracture the gels. With a reduction in INS Ca content, the yield stress decreased, whereas LT values increased indicating a weaker, more flexible casein network. Microstructure of rennet-induced gels near the GM point and 2 to 10 h after this point was studied using fluorescence microscopy. At GM, gels made from milk acidified to pH 6.4 exhibited more branched, interconnected networks, whereas strands and clusters became larger with a reduction in milk pH to 5.4. Gels made from milk with EDTA added had more finely dispersed protein clusters compared with gels made from milk with no EDTA added. These microscopic observations supported the effect of loss of INS Ca on GM and LT. There was a decrease in apparent interconnectivity between strands in gel microstructure during aging, which agreed with the decrease in G′ after GM. It can be concluded that low levels of solubilization of INS Ca and the decrease in milk pH resulted in an increase in GM. With greater losses of INS Ca there was excessive reduction in cross-linking within CM, which resulted in weaker, more flexible rennet gels. This complex behavior cannot be explained by adhesive hard sphere models for CM or rennet gels made from these CM.     

基于高分子载体与活性炭对比处理白酒废水的研究

实验以高分子材料做载体,与多孔颗粒活性炭(GAC)在完全相同的条件下,作厌氧流化床固定化微生物处理白酒废水的对比性研究.6d后加入已经分离出来的高效厌氧微生物,结果表明,新型高分子载体能有效促进厌氧菌固定化,可比GAC缩短反应器启动时间12d左右;且在进水COD值为3957.4mg/L、pH值为7.30、膨胀率为50%、水力停留时间为9h的条件下,COD的云除率为90.5%.     

柑橘渣水不溶性膳食纤维的性质研究

以柑橘渣水不溶性膳食纤维为研究对象,通过测定其表面结构、单糖成分、持水力、持油力、膨胀力及阳离子交换能力、羟自由基清除能力,研究其性质。结果显示:柑橘渣水不溶性膳食纤维表面松散无规则,呈网状结构;单糖成分中阿拉伯糖含量(37.45%)最高,其次为半乳糖(23.10%),半乳糖醛酸含量(8.74%)最低,且五碳糖含量为56.29%,六碳糖含量为34.97%;柑橘渣水不溶性膳食纤维具有良好的持水力、持油力、膨胀力、阳离子交换能力及羟自由基清除能力。     

酱油渣不溶性膳食纤维的制备及其功能特性研究

以酱油渣为原料,采用酶法辅助碱法制各不溶性膳食纤维,并测定不溶性膳食纤维的膨胀性、持水力、抗脂质过氧化以及吸附亚硝酸根离子等功能特性.实验结果表明,不溶性膳食纤维制备的最佳工艺参数为:NaOH浓度为4%,碱解温度为50℃,碱解时间为70min,酱油渣不溶性膳食纤维得率达37.89%.酱油渣不溶性膳食纤维具有良好的膨胀性、持水力、抗脂质过氧化和吸附亚硝酸根离子的作用,在胃液pH值条件下,在120min时不溶性膳食纤维吸附性能趋于饱和,吸附率达到72.6%,根据模拟方程求得在48.8min吸附率达到50%.     

芭蕉芋淀粉接枝丙烯酸制备高吸水性树脂的研究

在氮气保护的环境下,以芭蕉芋淀粉为原料,引发剂为过硫酸铵,交联剂是N,N-亚甲基双丙烯酰胺,采用水溶液聚合法制备芭蕉芋淀粉接枝丙烯酸高吸水性树脂。研究单体用量、引发剂和交联剂用量以及单体中和度等因素对吸水性能的影响。     

Abstracts: The properties and application of a novel amphiphilic polymer as an active interfacial modifier

pp.247–253 A peptide/silicone hybrid functional polymer composed of silk peptide and silicone resin with a hydrophobic alkyl group was investigated for its compatibility and functionality as a cosmetic ingredient. We have found this polymer provides characteristic functions to modify and control various interfacial properties and named it active interfacial modifier (AIM‐FN). At the liquid/liquid interface, AIM‐FN worked as an excellent W/O emulsifier for various oils, polar or non‐polar, and even for silicone oil. In principle AIM‐FN stays at the interface between the aqueous phase and lipid phase because it is not compatible with either phase. At liquid/solid interfaces, the peptide moiety of AIM‐FN attaches to the hydrophilic solid surface and makes it water repellant and water proof with its hydrophobic silicone and alkyl residue. An emulsion formulated with AIM‐FN gives a non‐oily and non‐tacky skin feeling as AIM‐FN improves the solid/solid (skin/skin) surface property.     

互穿网络型印花黏合剂的制备及应用

利用微乳液聚合方法,选用丙烯酸酯类单体和有机硅类功能性单体,制备具有互穿网络结构的新型环保涂料印花黏合剂.通过研究合成工艺条件对微乳液性能的影响,初步探索了黏合剂的应用性能.结果表明,选用B-196、V-20S组成的阴/非离子复配型乳化剂,在引发剂浓度为0.6%,引发剂一次性加入,反应温度为70～72℃的条件下,形成的乳液稳定;加入有机硅可提高印花织物柔软性和颜色性能.