Purification and characterization of keratinase from a new Bacillus subtilis strain

The aim of this study was to purify and characterize a keratinase produced by a new isolated Bacillus subtilis KD-N2 strain. The keratinase produced by the isolate was purified using ammonium sulphate precipitation, Sephadex G-75 and DEAE (diethylaminoethyl)-Sepharose chromatographic techniques. The purified enzyme was shown to have a molecular mass of 30.5 kDa, as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The optimum pH at 50 °C was 8.5 and the optimum temperature at pH 8.5 was 55 °C. The keratinase was partially inactivated by some metal ions, organic solvents and serine protease inhibitor phenylmethanesulfonyl fluoride (PMSF). Sodium dodecyl sulfate (SDS) and ethylene diamine tetraacetic acid (EDTA) had positive effect on the keratinase activity. Reducing agents including dithiothreitol (DTT), mercaptoethanol, L-cysteine, sodium sulphite, as well as chemicals of SDS, ammonium sulfamate and dimethylsulfoxide (DMSO) stimulated the enzyme activity upon a feather meal substrate. Besides feather keratin, the enzyme is active upon the soluble proteins ovalbumin, bovine serum albumin (BSA), casein and insoluble ones as sheep wool and human hair. Calf hair, silk and collagen could not be hydrolyzed by the keratinase.     

Enzymatic Treatment of Wool

Three proteases were applied to treatments of wool. The shrinkage, dyeing behavior, some physical and mechanical properties of treated wool were studied. Peroxymonosulfate(PMS) and lipase were used to pretreat wool before the treatment of it by protease. The results show that the shrink resistance of wool fabric is not obtained when it is treated only by the protease, but it is remarkably improved when the wool fabric is treated first by PMS or a lipase afterwards by protease. The rate of dyeing is increased when the wool is treated by protease or combination of oxidant/ lipase and protease. Whiteness, luster and softness of treated wool are improved, while the strength and elasticity are reduced.     

Low Temperature Dyeing and Shrinkage-Resistance Finishing of Wool by Composition of Salt-Ammonia and Enzyme Treatment

Wool top and knitted fabric were treated with ammonia in the presence of sodium chloride （salt-ammonia process）. The effectiveness of salt-ammonia process traditionally used as pretreatment for low temperature dyeing has been investigated for conferring shrink-resistance of wool. The pretreatmont of salt-ammonia process followed by enzymatic treatment has been proved that contribute to not only the enhancement of dyeing behavionr but also shrinkage-resistance in the present studies. A novel composition of salt-ammonia pretreatment, oxidized and reduced treatment as well as protease modification was recommended to achieve low temperature dyeing and shrinkage-resistance of wool. At the same time, the process conditions were optimized by orthogonal array and assessed by dye uptake rate, weight loss and area shrinkage. Laboratory experiments showed that the knitted fabric treated according to optimized conditions of the combined process, achieved not only improvement of dye abilities but also the strict requirement of machine-washable, representing a possible alternative to chlorination.     

Protease Selection and Technology Optimization in Biofinish of Wool

A process for the shrink - resist treatment of wool by protease with a hydrogen peroxide pretreatment (the Perzym process) has been studied. A protease, selected from several commercial proteases, has been found having higher activity in shrink - resist treatment, and its optimum technological conditions, which confer wool better shrinkproofing and less strength and elongation loss, have been obtained by an orthogonal factorial design approach. The study shows that it is possible for the wool to be conferred excellent machine washability by the Perzym process.     

Enzymatic Treatment for Shrink-proofing of Wool

Introduction Duetothescalestructureandresiliencyproperties, woolhasatendencytoshrinkundertheinfluencesof moisture,detergentsandagitation.Nowadaysthemost commerciallysuccessfulshrink proofingprocedureistheIWS/CSIROchlorine Hercosetttopprocessasa combinationofsubtractiveandadditivemethods[1,2]. However,apartfromyellowingandresultingasynthetichandle,thisprocessproducesabsorbableorganichalogen compounds(AOX)[1,3],whichcauseseverepressureon environmentallegislation[4,5].Forecologicaland econ…     

Environmental Friendly Route and Wool Shrink Proofing

The shrink proofing on wool with treatment of protease named Argaenzyme STL was studied. The various pretreating auxiliaries, different parameters for protease treating process and the effect of stabilizer were discussed in detail. The varieties of some properties before and after protease treatment were also investigated.     

亚硫酸氢钠等物质对莴笋生长规律及产量影响的研究

采用亚硫酸氢钠、白砂糖、尿素、磷及二氢钾等化学药剂及营养物质配合使用，对茎用莴苣进行叶面喷施。试验结果表明：用１５０ｐｐｍ的ＮａＨＳＯ３配以０．２％的白糖、０．２％的尿素、０．２％的ＫＨ２ＰＯ４进行叶面喷施效果最好，能增产２０．２２％，其中各种喷施物对产量影响白大到小的顺序依次为ＮａＨＳＯ３＞白糖＞尿素＋ＫＨ２ＰＯ４，Ｎ／Ｋ比例明显影响有机物的分配和嫩茎的生长情况．     

羊毛生物酶细化改性工艺研究

采用双氧水预处理并结合蛋白酶—脂肪酶工艺细化羊毛纤维。通过正交试验分别确定了羊毛双氧水预处理的条件和蛋白酶—脂肪酶处理工艺条件,并进行了生物酶细化处理羊毛的对比试验。结果表明采用双氧水预处理并蛋白酶-脂肪酶细化处理羊毛后,羊毛纤维鳞片层受到一定程度的破坏,纤维的直径降低约2.3μm,断裂强力保持率达到94.8%。     

Identification and characterization of a bacterial hydrosulphide ion channel

The hydrosulphide ion (HS(-)) and its undissociated form, hydrogen sulphide (H(2)S), which are believed to have been critical to the origin of life on Earth, remain important in physiology and cellular signalling. As a major metabolite in anaerobic bacterial growth, hydrogen sulphide is a product of both assimilatory and dissimilatory sulphate reduction. These pathways can reduce various oxidized sulphur compounds including sulphate, sulphite and thiosulphate. The dissimilatory sulphate reduction pathway uses this molecule as the terminal electron acceptor for anaerobic respiration, in which process it produces excess amounts of H(2)S (ref. 4). The reduction of sulphite is a key intermediate step in all sulphate reduction pathways. In Clostridium and Salmonella, an inducible sulphite reductase is directly linked to the regeneration of NAD(+), which has been suggested to have a role in energy production and growth, as well as in the detoxification of sulphite. Above a certain concentration threshold, both H(2)S and HS(-) inhibit cell growth by binding the metal centres of enzymes and cytochrome oxidase, necessitating a release mechanism for the export of this toxic metabolite from the cell. Here we report the identification of a hydrosulphide ion channel in the pathogen Clostridium difficile through a combination of genetic, biochemical and functional approaches. The HS(-) channel is a member of the formate/nitrite transport family, in which about 50 hydrosulphide ion channels form a third subfamily alongside those for formate (FocA) and for nitrite (NirC). The hydrosulphide ion channel is permeable to formate and nitrite as well as to HS(-) ions. Such polyspecificity can be explained by the conserved ion selectivity filter observed in the channel's crystal structure. The channel has a low open probability and is tightly regulated, to avoid decoupling of the membrane proton gradient.     

丙烯酰胺-N,N-二甲基二烯丙基氯化胺共聚物的合成及其作为絮凝剂的应用

利用过硫酸钾、亚硫酸氢钠、偶氮二异丁腈及其它助剂组成的复合引发体系,研究了在30℃下,丙烯酰胺(AM)与N,N-二甲基二烯丙基氯化胺(DMDAAC)在水溶液中的共聚合,得到了溶解性能好的阳离子共聚物(PDA).考察了pH值、引发剂用量和单体加料方式对阳离子共聚物粘度和阳离子度的影响.继而进一步研究了PDA作为絮凝剂在污泥脱水中的应用,其污泥脱水效果比目前市售的阳离子絮凝剂要好.     

酶复合整理改善羊毛织物的防缩性能

为解决单独用蛋白酶处理羊毛织物时防缩效果不明显且强力降低的问题,提出用碱性蛋白酶对羊毛织物进行处理,部分去除羊毛纤维的鳞片,在此基础上再用谷氨酰胺转胺酶对羊毛进行处理,实现羊毛纤维蛋白质分子之间的交联.扫描了整理前后羊毛织物的红外光谱图,这种酶复合整理工艺使得羊毛织物的防缩性能显著改善,而强力和伸长性能基本保持不变,从而更具应用价值.     

蛋白酶对毛织物的整理工艺

通过对各种试验条件的变化,我们得出了ＷＯ蛋白酶对毛织物后整理的最佳工艺条件。采用最佳工艺对毛织物实施生物整理之后,织物手感柔软丰满,色泽柔和、织纹清晰,提高了毛织物的悬垂性,织物的刺痒感得到大大改善,另外织物的毡缩性也得到大大改善,达到完全机可洗要求。     

The Biocompatibility of Wool Keratin

Keratin is the major structural fibrous protein providing outer covering such as hair, wool, feathers, etc. When being used as a kind of biomaterials, the biocompatibility of wool keratin is one of the most critical questions. By now, there has not been systemic study on the biocompatibiiity of keratin. Therefore, in this article we used the procedures of skin irritation, haemolysis and subcutaneous implantation according to ISO 10993 to study it. Moreover, the Fourier transform-infrared (FTIR) spectroscopy was utilized to analyse the impurity and structure modification of wool keratin film. The part of the animal tests showed that the wool keratin films prepared by authors were biocompatible. But the residual of sodium dodecyi sulfate (SDS) affected the results of other tests. Consequently, the wool keratin membrane is one kind of favourable and promising biomaterial for biomedical and histological utilization. The residual SDS used as an agent should be eliminated from the keratin solution or membrane completely if for biological usage. In conclusion, wool keratin, as a kind of natural protein, prospectively could be applied in biomedical materials and scaffolds of tissue engineering.     

碱性化学着色过程中不锈钢电势的测定

着重介绍了不同温度时碱性着色过程中不锈钢电势与着色时间的关系,并讨论了温度和添加剂亚硫酸钠对碱性着色过程的影响．     

超声波在洗毛中的应用

研究了不同条件下的超声波洗毛效果,并与传统乳化洗毛进行了对比.研究结果表明,利用超声波洗毛可以降低洗毛温度、缩短洗毛时间、降低洗剂和助剂用量.利用超声波所得的洗净毛蓬松性好,羊毛之间不发生纠缠,白度高且洗净毛中几乎无细小杂质.另外,超声波在洗毛的同时,对羊毛鳞片有蚀刻作用.经过超声波洗毛所得洗净毛纤维鳞片变钝、变光,摩擦效应降低.且超声波洗毛所得洗净毛纤维细度分布更趋集中,长时间超声波洗毛会使羊毛纤维直径变小,断裂伸长增大,但对纤维断裂强力无明显损伤.     

生物酶洗毛鞘氨醇杆菌Sphingobacteium sp.的筛选与表征

 羊毛纤维材料初加工普遍采用表面活性剂和无机盐作用的化学方法,此方法需要在较高温度和较强机械作用下进行,耗水耗能大,同时洗毛废水排放到自然界中造成环境污染严重,且纤维材料表面存在化学残留,影响洗净毛纤维的品质,易造成纤维损伤。为解决化学洗毛方法造成的环境污染和化学物质残留,本文研究了生物酶洗毛技术,在原毛表层污物中分离得到一株适于生物酶洗毛的高产脂肪酶菌株,经形态鉴定、16S rDNA菌种鉴定和生理生化指标鉴证,确定为脂肪酶产生鞘氨醇杆菌(Sphingobacterium sp.)。通过Rhodamine B显色培养基的荧光实验得出H/C值(荧光圈直径H与菌落直径C之比)为2。经酶活力测定,在30℃条件下鞘氨醇杆菌在11h达到产酶高峰(101.67U/mL)。经脂肪酶洗毛实验验证,洗净毛含脂率为1.031%,鞘氨醇杆菌对羊毛生物脱脂有较好的适用性。     

亚硫酸钙非均相氧化动力学的研究

在典型的温法烟气脱硫条件下，喷雾干燥脱硫产物中的亚硫酸钙非均相氧化动力学在中试装置中被研究，实验结果表明，亚硫酸钙氧化速率对氧是１级反应，对亚硫酸钙浓度分别是０级和０．７５级，这取决于不同的反应控制步骤。ｐＨ对氧化速率的影响是弱的。氧化速率随着ＭｎＳＯ４的添加而升高。在喷雾干燥脱硫产物温法氧化过程中，没有发现有ＳＯ２排出。     

氧化棉纤维经角蛋白溶液处理后的结构及性能研究

采用氢氧化钠和双氧水溶解羊毛制得可溶性角蛋白溶液,再对经高碘酸钠选择性氧化的棉纤维进行处理.研究了氧化棉纤维经角蛋白溶液处理后的结构和力学性能.结果表明,氧化棉纤维经角蛋白溶液处理后产生增重,同时在纤维表面吸附成膜,红外光谱表明角蛋白与氧化棉纤维之间形成共价结合,且氧化棉纤维经角蛋白溶液处理后的力学性能基本不变.     

苦荞类胰蛋白酶水解酶的纯化及部分性质研究

采用缓冲液提取、盐析、凝胶过滤及离子交换层析等方法，从苦荞种子中分离纯化出1种类胰蛋白酶水解酶，经十二烷基硫酸钠一聚丙烯酰胺凝胶电泳(SDS—PAGE)测得其分于量为67kD，等电聚焦(IEF)测得等电点为6．3．该酶可以水解胰蛋白酶的底物BApNA，而且其活性不受苦荞胰蛋白酶抑制剂的影响．通过比较，苦荞中的胰蛋白酶水解酶在性质上与报道的甜荞BAPAase极为相似，可能属于同一类蛋白酶．     

提高新疆细羊毛可纺支数的研究

为降低产品成本，充分利用较低品质支数原料纺出线密度较低的纱，织出优质高档产品满足市场要求，我厂根据新疆细羊毛品质特性，在常规工艺的基础上，对工艺路线及关键参数作了改进。本文着重论述用６４支毛条提高可纺支数（１９．２３～１７．８５ｔｅｘ即５２～５６公支细纱）的大生产工艺及实践效果。