产中性纤维素酶芽孢杆菌Y106产酶条件优化

筛选得到一株高产中性纤维素酶的芽孢杆菌Ｙ１０６,并对其发酵条件进行了优化,麸皮能够较大幅度地促进产酶,果糖是良好的诱导物,有机氮流促进产酶的效果优于无机氮源,最优的有机氮源是蛋白胨。Ｆｅ＾３＋、Ｆｅ＾２＋、Ｎａ＾＋、Ｃａ＾２＋可以促进纤维素酶的合成,而Ｃｕ＾２＋、Ａｇ＾＋、Ｃｏ＾２＋、Ｈｇ＾２＋则对合成起遏制作用,在酶反应系统中Ｆｅ＾３＋、Ｆｅ＾２＋、Ｃａ＾２＋、Ｍｇ＾２＋能激活纤维素酶活性,Ｃｏ     

Bacillus natto TK-2产γ-絮凝活性的研究

对γ-聚谷氨酸的絮凝活性进行了研究,得出了其最佳絮凝条件为:γ-聚谷氨酸投加浓度为10mg/L;絮凝体系的pH为7.0;γ-聚谷氨酸在80℃以下都能保持很高的絮凝活性;添加不同种类的K+,Na+,Ca2+,Mg2+,Fe2+,Fe3+,Al3+能不同程度地提高γ-聚谷氨酸的絮凝活性,其中添加Ca2+的助凝效果最好,最终选择Ca2+为最佳的助凝离子并确定添加浓度为100mg/L。     

Surface reaction of Bacillus cereus biomass and its biosorption for lead and copper ions

In this study, the surface chemical functional groups of Bacillus cereus biomass were identified by Fourier transform infrared （FTIR） analytical technique. It had been shown that the B. cereus cells mainly contained carboxyl, hydroxyl, phosphate, amino and amide functional groups. The potentiometric titration was conducted to explain the surface acid-base properties of aqueous B. cereus biomass. The computer program FITEQL 4.0 was used to perform the model calculations. The optimization results indicated that three sitesthree pKas model, which assumed the cell surface to have three distinct types of surface organic functional groups based on the IR analysis results, simulated the experimental results very well. Moreover, batch adsorption experiments were performed to investigate biosorption behavior of Cu（Ⅱ） and Pb（Ⅱ） ions onto the biomass. Obviously, the adsorption equilibrium data for the two ions were reasonably described by typical Langmuir isotherm.     

Stability of green fluorescent protein using luminescence spectroscopy: is GFP applicable to field analysis of contaminants?

Green fluorescent protein (GFP) was first isolated in the early 1970s for experimental use from coelenterates or the Pacific jellyfish. Aequorea victoria (Morin and Hastings, 1971). GFP has since become a favored biomarker in the photophysical analysis of molecular and cell biology because of its strong intrinsic visible fluorescence and the feasibility of fusing it to other proteins without affecting their normal functions (Creemers et al., 2000). Here we report using Bacillus subtilis expressing GFP to evaluate the influence of different environmental pH conditions on GFP fluorescence. Emission acquisitions were configured to excite at 471 nm and detect at an emission from 490 to 650 nm at 1-nm increments. Fluorescence intensity was significantly better at pH 7 (4.2 x 105 cps; P-value < 0.01) than at acid or alkaline conditions. GFP is a good biomarker for environments near netural conditions: however, GFP may be unsuitable where soils or waters are below or above pH 7 because of loss in fluorescence intensity. Alternative fluorescent markers and delivery systems must be examined in different environments to optimize responses from bioreporter molecules.     

嗜热脂肪芽孢杆菌过氧化氢酶基因perA在大肠杆菌中的高效表达

利用PCR技术得到嗜热脂肪芽孢杆菌 (Bacillusstearothermophilus)过氧化氢酶基因 perA ,将该基因与表达载体 pKK2 2 3 3连接构建重组质粒pK perA ,转化大肠杆菌过氧化氢酶HPⅠ和HPⅡ双缺突变株UM 2 ,得到重组大肠杆菌UM 2 1.酶活测定结果表明 ,表达产物具有正常的生物学活性 .SDS PAGE电泳结果显示出明显的特异性表达条带 ,单体Mr =86× 10 3 ,与嗜热脂肪芽孢杆菌所产酶相同 .实验表明 ,重组质粒在宿主UM 2中有较好的稳定性 ,在无选择压力条件下传代 6 0次基本保持稳定 ,传代 10 0次重组质粒保留 80 %以上 .摇瓶实验确定重组菌的最佳表达条件为 :IPTG浓度 ,0 .75mmol/L ;诱导时间 3h ;培养基起始 pH 6 .5 ;诱导温度 37℃ ;装液量 5 0mL/ 2 5 0mL .在优化条件下 ,重组菌产生的过氧化氢酶占菌体总蛋白的 8% ,酶活力可达 35U/mL ,是原始菌株BacillusstearothermophilusIAM110 0 1的 11.7倍 .图 2表 1参 10     

一株芽孢杆菌在低氮源浓度培养基中的生长与氨氮去除特性

对菌株YB3进行了16S rRNA基因序列进化分析,并分别以NH_4Cl、NaNO_2、NaNO_3、尿素和蛋白胨为单一氮源,配制了5种低氮源浓度培养基,研究YB3在与养殖水体相近营养水平条件下的生长与氨氮去除特性.结果显示,菌株YB3属于蜡样芽孢杆菌(Bacullis cereus),在5种培养基中均能够生长,菌悬液(吸光度OD600为1.0)接种量为1.0%(v/v)时,OD600由0.010增长到0.100~0.117.在NH_4Cl培养基中,YB3的氨氮去除速率为1.23 mg·L~(-1)·d~(-1),去除率为93.5%.在尿素、蛋白胨等有机氮源培养基中,YB3将首先导致氨氮的积累,累积倍数分别为51.69和3.38,之后开始去除,去除速率为1.56和0.29 mg·L~(-1)·d~(-1),去除率为93.7%和26.8%.结果也表明,提高YB3接种量至8.0%(v/v),可以使蛋白胨培养基氨氮累积倍数下降至2.02,去除速率提高至1.07 mg·L~(-1)·d~(-1),去除率最终达到98.4%.NaNO_2和NaNO_3培养基中均未检测到氨氮,而NH_4Cl、尿素和蛋白胨培养基中也未检测到NO_2~--N和NO_3~--N,表明YB3的硝化、亚硝化和反硝化作用均不强烈,去除氨氮的同时将不会造成NO_2~--N和NO_3~--N等的大量积累.本文为菌株YB3在养殖水体调控与净化中的应用研究提供了实验基础和理论支持.     

蜡样芽孢杆菌中甲酸脱氢酶基因产氢研究

通过基因筛选,成功分离并克隆到蜡样芽胞杆菌XN12（Bacillus cereus XN12）的甲酸脱氢酶基因fdhF（formate dehydrogenase）,该基因全长2937bp,GC含量39.3%,编码978个氨基酸,与已报道的蜡样芽孢杆菌Q1的fdhF基因（GenBank No.CP000227.1）同源性达到100%.将其连接在表达载体pET32a上并融合His标签,构建了重组质粒pET32a-FDHF-His,转入大肠杆菌BL21（Escherichia coli BL21）后获得了高效表达.重组菌株经IPTG诱导后经WesternBlot分析表明,重组蛋白分子量约为108kDa.通过对重组菌株产氢性能试验表明,重组菌对提高产氢率具有一定促进作用,产氢量为每消耗1mol的葡萄糖和甲酸盐分别能产生0.73mol和0.20mol的氢气.     

地衣芽孢杆菌(Bacillus licheniformis)对 Cr6+的吸附动力学研究

从污染土壤中分离出地衣芽孢杆菌(Bacilluslicheniformis),利用其死菌体对Cr6 溶液进行吸附动力学研究.在Ci=300mg/L、pH=2.5和θ=50℃条件下,吸附120min获得最大吸附量60.5mg/g.应用Langmuir和Freundlich吸附等温线研究,结果表明,Langmuir吸附等温线更为适合.动力学研究显示,地衣芽孢杆菌对Cr6 的吸附动力学可以用拟二级速度方程进行描叙.图3表4参14     

枯草芽孢杆菌H110对苹果梨采后青霉病和黑斑病的抑制效果

将具有广谱拮抗作用的枯草芽孢杆菌(Bacillus subtilis)H110作为生防菌株,研究了该菌的培养液、滤液、菌悬液及蛋白粗提液对苹果梨(Pyrus bretschneideri Rehd.)青霉病(Penicillium expansum Link)和黑斑病(Alternaria alternate)的抑制效果.H110的蛋白粗提液的抑制作用最好,青霉病和黑斑病的发病率分别比对照低92.7%和86.6%,病斑直径也显著小于对照;其次为菌培养液和菌悬液,滤液的抑制效果相对较差,但4种处理均显著好于对照.4种处理对病原菌孢子萌发的抑制效果与in vivo试验的效果一致.实验结果表明,枯草芽孢杆菌通过产生抗菌蛋白和竞争作用抑制病原菌生长.图1表2参17     

芽胞杆菌属(Bacillus sp.)10株细菌混合制剂对4种作物出苗及苗期生长的影响

以10株具有促生及抑制病害的芽胞杆菌属菌株(Bacillus sp．)的培养物，按不同比例配制成5个混合剂型细菌制剂．A、B、C、D剂型播种时接种不结球小白菜30d后，株高、叶片数、根长和干重分别增加7．8％、6．2％、9．4％和13．8％，除C处理的株高与对照差异不显著外，其余均达显著水平．接种A和B剂型显著提高豌豆出苗率，出苗9d时两菌剂处理的地上和地下部干重分别平均提高92．3％和183．3％，并发现5株供试菌株对引起豌豆病害病原菌有明显的抑菌作用．以A、B、E三个剂型菌悬液培养水稻种子4d时，各处理的平均芽长提高33．3％，根长提高16．0％，培养25d时株高、根数和地上部干重平均分别提高16．0％、9．5％和22．7％，均达显著水平．B剂型的培养物培养小麦27d时发现对株高、叶片数和植株干重的影响都不显著，但对根数和根重有显著的促进作用．综合分析认为，A菌剂最有利于供试作物出苗和苗期生长，其次为B剂型．表5参17