Cu(Ⅱ)螯合壳聚糖磁性微球固定化胃蛋白酶的制备及性能研究

将Cu(Ⅱ)螯合壳聚糖磁性微球用作固定化胃蛋白酶的载体,讨论了固定化时间、pH值和给酶量对酶固定化的影响.确定最适固定化条件为:固定化时间1.0 h、pH值4～5、给酶量150 mg·(g载体)-1.与自由酶比较,固定化胃蛋白酶的催化特性和稳定性均令人满意.     

反胶束体系中固定化胃蛋白酶的催化性质研究

将胃蛋白酶加至CTAB(十六烷基三甲基溴化铵)/环己烷/正辛醇反胶束体系中得到固定化胃蛋白酶,研究了反胶束含水率、乙醇体积分数对固定化胃蛋白酶活力的影响,并对固定化胃蛋白酶和游离胃蛋白酶的催化性质进行了比较研究.结果表明,反胶束含水率为12％、乙醇体积分数为30％时,固定化胃蛋白酶的活力达到最佳;固定化胃蛋白酶和游离胃...     

氨基树脂固定胃蛋白酶的方法及性质研究

采用氨基树脂作为载体,戊二醛作为交联剂,对胃蛋白酶的固定化进行了研究,并对固定化条件和固定化胃蛋白酶的部分酶学性质进行了分析。确定固定条件为：戊二醛浓度为5%,载体处理温度为室温（25℃）,处理时间为5h,m（胃蛋白酶）：m（氨基树脂）为1：25,pH为3.0,固定时间为12h。此条件下固定化的胃蛋白酶活力为30U/g,酶的活力回收率为60%。与非固定化相比最适水解温度由50℃升高到60℃,最适pH值由2.0升高到4.0,游离酶米氏常数3.08g/L,固定化酶米氏常数1.2g/L,固定化胃蛋白酶的储存半衰期约为25天。对珠蛋白的操作半衰期为9天。     

磁性硅基壳聚糖微球固定化柚苷酶水解柚皮苷的研究

本文在磁性Fe3O4外包覆一层SiO2,再在其外包裹壳聚糖制备出磁性硅基壳聚糖微球（MSC）,对MSC进行环氧基修饰后用于柚苷酶的固定化研究,并对磁性硅基壳聚糖微球固定化柚苷酶水解柚皮苷的pH、温度、操作和储藏稳定性进行了考察。通过单因素实验,确定了环氧基修饰的磁性硅基壳聚糖微球（MSCE）固定化柚苷酶的最佳工艺条件为：pH 3.0,温度30 ℃,时间4 h、给酶量57.48 U/mL。在此条件下,MSCE固定化柚苷酶的载酶率、酶活回收率和酶比活力分别为31.29%、88.92%和409.33 U/g。与游离柚苷酶相比,MSCE固定化柚苷酶用于水解柚皮苷具有良好的pH稳定性和温度稳定性,重复使用8次后仍具有53.36%的相对酶活力,4 ℃条件储存一个月后仍具有80.97%的相对酶活力。     

磁性硅基壳聚糖微球固定化柚苷酶水解柚皮苷

在磁性Fe3O4外包覆一层SiO_2,再在其外包裹壳聚糖制备出磁性硅基壳聚糖微球(MSC),对MSC进行环氧基修饰后用于柚苷酶的固定化研究,并对磁性硅基壳聚糖微球固定化柚苷酶水解柚皮苷的pH、温度、操作和储藏稳定性进行了考察。通过单因素实验,确定了环氧基修饰的磁性硅基壳聚糖微球(MSCE)固定化柚苷酶的最佳工艺条件为:pH 3.0,温度30℃,时间4 h、给酶量57.48 U/mL。在该条件下,MSCE固定化柚苷酶的载酶率、酶活回收率和酶比活力分别为31.29%、88.92%和409.33 U/g。与游离柚苷酶相比,MSCE固定化柚苷酶用于水解柚皮苷具有良好的pH稳定性和温度稳定性,重复使用7次后仍具有53.36%的相对酶活力,4℃条件贮存30 d后仍具有80.97%的相对酶活力。     

磁性壳聚糖微球固定化酵母细胞及其用于发酵生产酒精的研究

通过溶胀一吸附法用磁性壳聚糖微球固定化酵母细胞,考察了磁性壳聚糖微球固定化酵母细胞的效果.结果表明,大量酵母细胞被固定在磁性微球表面,且磁性壳聚糖微球可重复使用.以所制备的磁性固定化酵母细胞发酵生产酒精,发酵醪液的酒精度高于悬浮酵母细胞发酵醪液的酒精度,重复使用磁性壳聚糖微球固定化酵母细胞再次发酵,醪液的酒精度虽然有所下降,但是仍高于悬浮酵母细胞发酵的酒精度.     

磁性纳米粒子的制备及脂肪酶的固定化

建立了以纳米级磁性粒子为载体固定化脂肪酶的方法,优化了脂肪酶的固定化条件,考察了固定化酶的性质. 制备的磁性载体平均粒径20 nm,具有超顺磁性,分散和再分散效果好. 固定化酶的最适吸附时间为60 min,酶用量:载体量为1:1,固定化酶的酶活达到718 U/g. 结果表明,经纳米磁性粒子固定化后,脂肪酶得到活化,固定化酶比活为游离酶的1.8倍. 同时,固定化脂肪酶的pH稳定性显著提高.     

磁性高分子微球固定化酶的制备及应用

利用磁性高分子微球通过化学反应固定化酶,可以借助外部磁场方便地分离回收固定化酶,将固定化酶放入磁场稳定的流动床反应器中还可以减少持续反应体系中的操作.简要地介绍了磁微球的制备方法,包括包埋法、分散聚合、乳液聚合和悬浮聚合,对磁性微球固定化酶的制备方法和原理进行了探讨,论述了磁性高分子微球固定化酶的特点及应用.     

固定化胃蛋白酶的工艺优化

利用海藻酸钠-壳聚糖对胃蛋白酶进行固定化,以酶活回收率为指标,探讨不同的氯化钙浓度、固定化时间、游离胃蛋白酶稀释倍数、海藻酸钠浓度对固定化胃蛋白酶效果的影响。采用响应面分析法进行固定化工艺优化。结果表明:海藻酸钠浓度最佳固定化浓度为0.9%,游离酶稀释倍数为10倍,氯化钙浓度为3.6%,固定化时间为1.5 h,该条件下固定化酶的酶活回收率为73.42%,连续反应5次,相对酶活力仍为61.20%。     

磁性固定化技术在环境工程领域的研究和应用进展

磁性固定化技术凭借其独特的磁学优势,在环境工程领域具有广阔的应用前景。本文综述了磁性固定化载体种类和磁性固定化方法,着重论述了近年来磁性固定化技术在环境监测、废水及废气治理中的应用情况,并对该项技术在磁性载体的制备、探索微生物与磁性载体固定结合新方法及开发工业化应用技术等方面进行了展望。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料，介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比，介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序，对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

Inorganic/organic nanocomposite coatings: The next step in coating performance

Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled. An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible. UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Some Large Wood-Boring Beetles in Southeastern USA

Ethanol and α-pinene were tested as attractants for large wood-boring pine beetles in Alabama, Florida, Georgia, North Carolina, and South Carolina in 2002–2004. Multiple-funnel traps baited with (−)-α-pinene (released at about 2 g/d at 25–28°C) were attractive to the following Cerambycidae: Acanthocinus nodosus, A. obsoletus, Arhopalus rusticus nubilus, Asemum striatum, Monochamus titillator, Prionus pocularis, Xylotrechus integer, and X. sagittatus sagittatus. Buprestis lineata (Buprestidae), Alaus myops (Elateridae), and Hylobius pales and Pachylobius picivorus (Curculionidae) were also attracted to traps baited with (−)-α-pinene. In many locations, ethanol synergized attraction of the cerambycids Acanthocinus nodosus, A. obsoletus, Arhopalus r. nubilus, Monochamus titillator, and Xylotrechus s. sagittatus (but not Asemum striatum, Prionus pocularis, or Xylotrechus integer) to traps baited with (−)-α-pinene. Similarly, attraction of Alaus myops, Hylobius pales, and Pachylobius picivorus (but not Buprestis lineata) to traps baited with (−)-α-pinene was synergized by ethanol. These results provide support for the use of traps baited with ethanol and (−)-α-pinene to detect and monitor common large wood-boring beetles from the southeastern region of the USA at ports-of-entry in other countries, as well as forested areas in the USA.