共查询到19条相似文献，搜索用时 593 毫秒
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通过测定几丁质酶活力的方法对来源于不同寄主和采集地的16株玫烟色棒束孢进行筛选,获得活性较高菌株RCEF3304,并对高活力菌株RCEF3304产几丁质酶的pH值、装液量、接种量和温度等发酵条件进行优化研究。结果表明高酶活菌株产酶最适条件:胶体几丁质2%,NaNO33%,Mg2+0.05%,培养基初始pH值6.0,接种量12%,100 mL装液量为10 mL,温度25℃和培养时间36 h;最适发酵工艺条件下,几丁质酶酶活OD值达到0.486,比优化前发酵水平提高了128%。 相似文献
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金鱼淀粉酶性质的初步研究 总被引：2，自引：0，他引：2
以金鱼肠及肝胰脏为材料,匀浆抽提离心得粗酶液并对酶性质做初步研究．结果表明：肠淀粉酶与肝胰脏淀粉酶催化淀粉水解的最适pH值分别是6．8,6．2;最适底物浓度分别是0．02％,0．03%最适温度分别是35℃,30℃．并进一步研究一、二价金属离子和重金屑离子对该鱼淀粉酶活力的影响,结果显示。一价金属离子K^＋、Na^＋对酶活力没有影响;二价金属离子Mg^2＋、Ba^2＋对酶活力具有抑制作用,但Ca^2＋对酶活力具有促进作用l重金属离子Hg^2＋、Cd^2＋有明显的抑制作用． 相似文献
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纯化了黑曲霉Aspergillus niger FJL0801糖化酶,并对其酶学性质进行研究.粗酶液经纯化后,较粗酶液纯化了38.42倍,酶活回收率达到17.45%.酶最适作用温度为60℃;最适反应pH值为4.5;在60℃下,保温2 h后,相对酶活42%±2.8%.在pH4.5,60℃下,作用时间在60 min以内,其酶活保存89%±2.56%;其酶学性质符合淀粉糖化工业化过程中对酶的要求,该酶比较适合应用于淀粉糖化工业. 相似文献
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生淀粉糖化菌的选育及发酵条件 总被引：1，自引：0，他引：1
以黑曲霉(Aspergillus niger)523原生质体为对象,经激光、紫外线和亚硝基胍复合诱变,选育出高产生淀粉糖化酶突变株黑曲霉NL-3,其生淀粉酶活力为156μ/ml.产酶最适培养条件为:起始pH4.5,30℃,72小时.K~+、Mg~(2+)对NL—3产生淀粉糖化酶有促进作用;Z_n~(2+)对产酶有抑制作用.酶的最适作用条件为:以玉米淀粉为底物时最适温度50℃,最适pH4.5;以甘薯淀粉、马铃薯淀粉为底物时最适温度60℃,最适pH4.0—4.5.酶在60℃保温15分钟,玉米淀粉为底物的酶剩余活力80%.甘薯淀粉、马铃薯淀粉为废物的酶剩余活力98%. 相似文献
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通过单因素试验和均匀试验设计,确定了米曲霉R519产木聚糖酶.结果表明：米曲霉R519产木聚糖酶最适反应条件是温度为60℃,pH值为4.5,酶液用量与底物用量比值为1/9.酶学性质Co^2＋和Fe^2＋对酶具有强烈的激活作用,Ca^2＋和Zn^2＋具有强烈的抑制作用. 相似文献
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通过对不同硫酸铵饱和度沉淀所得的牛肝中皂苷酶活力的比较,筛选出较高生物活性皂苷酶,确定了最佳硫酸铵饱和度为55%.酶性质及酶反应最适条件的研究表明：水解穿山龙皂苷的酶反应最佳底物浓度为2%、最佳酶反应时间为4h、最适反应温度为42℃、最适pH值为5.0. 相似文献
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N-乙酰-β-D-氨基葡萄糖苷酶(N-Acetyl-β-D-glucosaminidase,简称NAGase,EC.3.2.1.52)与凡纳滨对虾(Litopenaeus vannamei)的周期性蜕壳生长密切相关.以成虾外壳膜与肝胰腺为提酶材料,研究比较不同组织来源的NAGase活力与基本性质的异同.结果表明:不同组织来源的酶活力有差异,外壳膜NAGase活力为72 U/mg蛋白,肝胰腺的酶为60 U/mg蛋白;两种组织来源的NAGase酶促反应最适pH均为5.5,最适温度分别为30℃与37℃.并进一步比较不同部位来源酶的动力学参数(Km、Vm)、酶促反应活化能(Ea)及对Cu2 、Zn2 和Hg2 的敏感性等,阐明外壳膜与肝胰腺的NAGase酶学差异. 相似文献
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从白酒大曲中分离纯化米曲霉菌种,对其进行发酵培养;再对米曲霉的发酵干曲中性蛋白酶进行分离,并对其酶学性质进行研究.结果表明：米曲霉中性蛋白酶的最佳提取方法为加入生理盐水,置于恒温（30℃）下,提取30 min.硫酸铵沉淀中性蛋白酶的最适浓度为80%.该中性蛋白酶的最适作用温度为55℃,最适pH值为7.0,该酶在40℃下的稳定性较好,该中性蛋白酶pH稳定范围为6.0～8.0;NaCl和EDTA对中性蛋白酶活力具有抑制作用. 相似文献
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范韵敏 《Journal of Zhangzhou Technical Institute》2012,14(2):20-25
通过盐析透析、离了层析、疏水层析,对链霉菌属发酵液中的阿魏酸酯酶（FAE）进行分离纯化。并进行酶学性质研究。得出的阿魏酸酯酶的纯化倍数为2．67,回收率为55．8％,酶分子约为30kDa。其最适反应pH约为6．0,最适温度约为50℃,金属离子Cu^2＋和Zn^2＋对阿魏酸酯酶酶活力均有明显的抑制作用,而Mg^2＋、Fe^2＋、Ca^2＋、Na^＋和Mn^2＋对酶的活性均有一定的促进作用。 相似文献
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Analysis of both chitinase and chitosanase produced by <Emphasis Type="Italic">Sphingomonas</Emphasis> sp. CJ-5 总被引：1，自引：0，他引：1
A novel chitinolytic and chitosanolytic bacterium, Sphingomonas sp. CJ-5, has been isolated and characterized. It secretes both chitinase and chitosanase into surrounding medium in response to chitin or chitosan induction. To characterize the enzymes, both chitinase and chitosanase were purified by ammonium sulfate precipitation, Sephadex G-200 gel filtration and DEAE-Sepharose Fast Flow. SDS-PAGE analysis demonstrated molecular masses of chitinase and chitosanase were 230 kDa and 45 kDa respectively. The optimum hydrolysis conditions for chitinase were about pH 7.0 and 36 °C, and these for chitosanase were pH 6.5 and 56 °C, respectively. Both enzymes were quite stable up to 45 °C for one hour at pH 5~8. These results show that CJ-5 may have potential for industrial application particularly in recycling of chitin wastes. 相似文献
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腐殖酸对钴、镉作用的研究 总被引：10，自引：0，他引：10
本文采用碱溶酸沉法提取土壤中的腐殖酸,研究对Co2+、Cd2+的吸附作用机理.结果表明:最佳pH范围为6～7,吸附过程属于放热过程.用该种腐殖酸样品吸附Co2+服从Langmuir和Freudlich吸附等温模型,19℃、35℃、45℃的饱和吸附量为12.51、9.52、8.30mg/g;吸附Cd2+在19℃、35℃时服从Langmuir和Freundlich吸附等温模型,饱和吸附量为33.90、33.43mg/g,但在45℃时主要服从Freundlich吸附等温模型.腐殖酸对Co2+、Cd2+的吸附是通过两级络合反应形成配合物的方式结合. 相似文献
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对不同温度、pH、水浴时间下杏鲍菇菌柄中SOD酶比活性及其保留率进行研究,结果表明,杏鲍菇菌柄具有较高的SOD活性,25℃下,比活性可达351.4U/mg prot,最适宜保存其活性的pH为7.80,杏鲍菇菌柄中的SOD热稳定性突出,即使在100℃下水浴15min后,其SOD酶活保留率仍然高达74.17%（以25℃时测定活性为100%）,具备优良的加工性能,但长时间的高温条件会使SOD酶活性的逐渐下降。 相似文献
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用涂布平板法从温泉水中分离到1株产高温蛋白酶的嗜热菌,命名为P4.通过对菌株P4的生理生化试验和16S rRNA基因鉴定,初步确定其为一株嗜热脂肪地芽孢杆菌(Geobacillus stearothermophilus).菌株P4所产蛋白酶的最适反应温度在65-75℃之间,最适催化pH值为8.0,Zn2+、Mg2+对菌... 相似文献
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The aim of this study was to purify and characterize a keratinase produced by a new isolated Bacillus subtilis KD-N2strain. 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 30.5kDa, as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The optimum pH at 50℃ was 8.5 and the optimum temperature at pH 8.5 was 55℃. 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. 相似文献
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Preparation of Glutaraldehyde Cross-Linked Chitosan Beads Under Microwave Irradiation and Properties of Urease Immobilized onto the Beads 总被引：4，自引：0，他引：4
The glutaraldehyde cross-linked chitosan beads were prepared under microwave irradiation and urease was immobilized onto the beads. The activity and the yield of enzyme activity of the immobilized urease were 10.83 U/g carrier and 47.7%, respectively. The optimum conditions of immobilization were 1% of glutaraldehyde volume fraction, 10 mg/g of urease/beads weight ratio, 24 h of the processing time and pH 6.5 of the reaction medium for immobilization. The properties of the immobilized urease were investigated and compared with those of the free enzyme. The optimum pH values were 6.5 and 7.0 for the immobilized and free urease, respectively. The optimum temperature was 60℃ for the free urease, while it shifted to 65 ℃ for the immobilized enzyme. The Michaelis constant Kr, was 9.1 mmol/L for the immobilized and 12.5 mmol/L for the free urease. The immobilized urease retained 40% of its initial enzyme activity even after 10 repeated uses. The immobilized urease stored at 4 ℃ retained 46% of its initial activity even after 35 d. 相似文献
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本实验首次采用超声波辅助提取黑豆皮红色素,应用正交法优化黑豆中红色素提取的工艺条件及研究超声波对黑豆中红色素提取的影响。结果表明,最佳提取工艺条件：提取液为9%盐酸,料液比1：25（g/mL）,温度为70℃,提取时间为2h,超声波功率为100%。黑豆皮红色素在维生素C、NaCl、柠檬酸等食品添加剂存在下稳定性好;红色素耐还原性能力较强,对光和氧化剂不稳定;Fe3＋、Zn2＋、Cu2＋等金属离子对红色素的稳定性影响较大,Ca2＋、Al3＋对红色素稳定性影响较小。 相似文献