枯草芽孢杆菌基因组知识的生物学意义及对生物工程学的影响

基因组学的出现极大地影响了微生物学的基础研究和应用研究．枯草芽孢杆菌（Bacillussubtilis）是一个用于基础研究和生物工艺研究的重要模式细菌．从它的基因组获得的知识远比长期以来用传统的方法获得的信息要多．通过先进的方法分析其基因组和转录组，基本弄清了关于枯草芽孢杆菌染色体结构的信息，已经达到了能够阐明其基因表达过程的水平，使得完全掌握枯草芽孢杆菌分泌途径的生物化学操作成为可能，这将成为生物工艺学的重大成果、在理论上，随着对它的分析越来越细致，已经阐明一个遗传学的海量信息的新观念，直至获得理解再造一个细胞所需的最小的基因组的知识．总之，枯草芽孢杆菌基因组知识已经明显地更新了基础知识向应用微生物学和生物工艺学转化的途径，并使这种细菌成为后基因组微生物学的重要工具．     

不同处理对苏云金杆菌187菌株毒力的影响

以致倦库蚊作供试昆虫 ,对 187菌株的毒力进行测定 ,其效价为 2 16× 10 4IU mg- 1 并对摇床振荡时间、超声波处理等因素对晶体毒力的影响也进行了探讨 ,结果表明延长振荡时间以及用超声波处理均能够增加晶体毒力     

几株Bt菌株对紫外线的抗性探讨

采用不同照射时间的紫外光（UV）对1株野生型Bt菌株及3株Bt菌株Bt001、Bt200、Bt087进行照射处理后再置于双碟上培养16h，结果表明，Bt野生菌株在UV处理3min后已基本全部失活，而Bt001、Bt200、Bt087在UV处理8min后仍有活性。从UV处理时间的长短及平板上出现菌落数的多少得知，尽管菌株Bt001、Bt200、Bt087对UV的抗性都比野生Bt菌株强得多，但并不相等。其中，Bt200相对弱些，UV处理9min后已无菌落；Bt087最弱，UV处理8min后已无菌落；而菌株Bt001对UV的抗性最强，UV处理13min后仍有菌范出现。这说明不同的Bt菌株，其遗传背景是不同的。另外，Bt001经紫外线照射9min，培养16h后发现有9个菌落发生明显的变异，菌落呈棕黄色，菌落明显比原始菌落小。涂片，油镜下观察其菌体要比原始菌体小，此为明显发生突变的菌株。     

Adsorption of Cu^2 ＋, Zn^2＋ and Cd^2＋ on Bacillus subtilis

A process of biosorption of Cu2 , Zn2 and Cd2 on Bacillus subtilis was investigated. The experiments show that the process of biosorption is quite fast. The maximum adsorption was reached after 5 min and hardly changed with time. The experimental data was analyzed using four sorption kinetic models: the pseudo-first-order, the Ritchie second-order, the modified second-order and the Elovich equations, which helped to determine the best-fit equation for the sorption of metal ions onto biomass. The results show that both the Ritchie second-order and modified second-order equations can fit the experimental data. The Langmuir model is able to accurately describe adsorption of Cu2 and Zn2 on B. subtilis. The experimental data points of adsorption Cd2 and Zn2 on B. subtilis are described by Freundlich isotherms model.     

一株脱硅胶质芽孢杆菌的分离与初步鉴定

本文利用无氮铝硅酸盐矿物选择性培养基，从土壤、铝土矿等样品中分离得到10株产荚膜的芽孢杆菌。对其中编号为GSY-1的菌株的生物脱硅试验结果表明：在pH7．2，30℃，200r／min后，矿浆含量5％，浸出时间7d，铝土矿矿样的A／S从10．30提高到13．48，增幅达30．87％，差异显著，由此确定该菌株具有一定的铝土矿脱硅能力。通过对GSY-1菌株的细胞形态、培养条件及生理生化特征的测定并与模式株对照，可初步鉴定为硅酸盐胶质芽孢杆菌。     

Optimization of cultural conditions for thermostable β-1, 3-1, 4-glucanase production byBacillus subtilis ZJF-1A5

The optimization of cultural conditions for β-glucanase production byBacillus subtilis ZJF-1A5 was investigated in flask trials. Temperature had great effect on β-glucanase production which maximized at optimal temperature of 37°C and decreased significantly when temperature was over 37°C. Charge quantity affected β-glucanase production significantly. Adding oxygen vector N-dodecane or acetic ether benefited β-glucanase production, but it depended on the concentration and charge quantity. The results of fractional factorial design showed that age and size of inoculum and shaking speed were the key factors affecting β-glucanase production and the cultivation time span to reach the highest β-glucanase activity. The optimal cultural conditions for β-glucanase production obtained with CCD were as follows: inoculum age and size (16 h, 3.82% (v/v)), shaking speed 210 r/min, charge quantity of 30 mL in 250 mL flask and initial pH 7.0, cultured at 37°C for 50 h. Repeated experimental results accorded with those predicted by a second-order polynomial model. The amount of β-glucanase, α-amylase and neutral protease produced byB subtilis ZJF-1A5 was associated partially with cell growth. Those three enzymes' activities increased following the cell growth and increased significantly when cells entered the stationary phase. Project (No. B0608) supported by the National Natural Science Foundation of China and a grant (2001121B25) from Hangzhou Science and Technology Development Project of Zhejiang Province, China     

Improved elastase production by Bacillus sp. EL31410─further optimization and kinetics studies of culture medium for batch fermentation

INTRODUCTION Elastase is an enzyme that attacks and solubi-lizes elastin. As elastase can degrade elastin (Mori-hara, 1967) that other proteases cannot; it has broad applications in medical therapy, food processing and daily use chemicals industry. Considerable eff- orts were made to screen the elastase-producing strains, to study its pathogen effect and its charac-terizations (Tsuzuki and Oka, 1965; Tsai et al., 1988; Sharon et al., 1997; Ozaki and Shiio, 1975). Shiio, 1975). Reporte…     

纳豆菌液态产酶条件的优化

实验采用单因素试验优化纳豆菌液体发酵条件。通过蛋白凝块溶解时间法测定纳豆激酶活力,筛选出最佳培养条件。液态发酵选用甘油、乳糖以及木糖与葡萄糖的混合糖代替基础培养基中的麦芽糖;用酵母膏、干酪素、胰蛋白胨和黄豆汁代替基础培养基中的麸皮进行发酵产酶试验,筛选出最佳碳氮源,并在此基础上变换不同的碳、氮源浓度,筛选出最佳的碳、氮比。试验结果表明：液态发酵最佳条件为,甘油10％,酵母膏2％,明胶0．5％,NaCl 0．5％,KH2PO4 0．1％,K2HPO4 0．4％,MgSO4 0．05％,初始pH7．0。在此条件下培养,测得的纳豆激酶活力相当于尿激酶1081．22IU／mL。与此前报道结果800．50IU／mL相比有了明显的提高。     

Effect of temperature on batch elastase production by Bacillus sp. EL31410

The production of elastase by Bacillus sp. EL31410 at various temperatures was investigated. In order to study the effect of temperature on elastase fermentation, different cultivation temperatures, ranging from 39 ℃ to 28 ℃, were evaluated in shake flask. The result indicated that 37 ℃ was best for cell growth at earlier stage; while maximum elastase activity was obtained when the cells were cultivated at 30 ℃. This result was verified by batch fermentation in 5-L bio-reactor under 37 ℃ and 30 ℃ temperature, respectively. The specific cell growth rate at 37 ℃ was higher than that at 30 ℃ during earlier stage of cultivation. The maximum value [5.5 U/(h-g DCW)] of elastase formation rate occurred at 24 h at 30 ℃ compared to 4.6 U/(h-g DCW) at 30 h at 37 ℃. Based on these results, two-stage temperature shift strategy and oscillatory temperature cultivation mode were evaluated in the next study. When compared to single temperature of 37 ℃ or 30 ℃, both two-stage temperature shift strategy and os     

Enhanced production of elastase by Bacillus licheniformis ZJUEL31410： optimization of cultivation conditions using response surface methodology

Sequential methodology based on the application of three types of experimental designs was used to optimize the fermentation conditions for elastase production from mutant strain ZJUEL31410 of Bacillus licheniformis in shaking flask cul- tures. The optimal cultivation conditions stimulating the maximal elastase production consist of 220 r/min shaking speed, 25 h fermentation time, 5% (v/v) inoculums volume, 25 ml medium volume in 250 ml Erlenmeyer flask and 18 h seed age. Under the optimized conditions, the predicted maximal elastase activity was 495 U/ml. The application of response surface methodology resulted in a significant enhancement in elastase production. The effects of other factors such as elastin and the growth factor (corn steep flour) on elastase production and cell growth were also investigated in the current study. The elastin had no significant effect on enzyme-improved production. It is still not clear whether the elastin plays a role as a nitrogen source or not. Corn steep flour was verified to be the best and required factor for elastase production and cell growth by Bacillus licheniformis ZJUEL31410.