油藏调剖菌TP-1的培养条件及岩芯模拟驱油研究

从油井产出水中分离得到一株兼性厌氧芽孢杆菌TP-1, 该菌株可在55℃的油藏温度生长, 并代谢产生粘性多糖和气体。经培养条件优化, 发酵液多糖产量可达5.5 g/L, 产气量为22 mL/L。低浓度的CaCl2、MgSO4和AlCl3对多糖的生成有促进作用。岩芯模拟试验表明, 该菌的注入可使岩芯压力增加, 提高石油采收率7.37%。TP-1是一株性能良好的油藏调剖菌。     

芽胞杆菌B13功能的初步研究

用选择性培养基从土壤中分离到芽胞杆菌B13。结果表明：芽胞杆菌B13能够同时溶解无机磷和分解有机磷,并且芽胞杆菌B13活菌及其发酵液能够抑制烟草青枯病菌和黄曲霉的生长;共培试验证明芽胞杆菌B13能够抑制烟草疫霉的生长;盆栽试验证明芽胞杆菌B13对烟草青枯病具有一定的防治效果。可以进一步将其开发出集解养分与抗病于一体的微生物活体制剂。     

建立维生素K_1微生物限度测定方法

目的:根据计数培养基适用性检查和计数方法适用性试验结果,建立维生素K1微生物限度测定方法。方法:以聚山梨酯80作为乳化剂,使维生素K1在p H 7.0无菌氯化钠-蛋白胨缓冲液中充分乳化。取1:20供试液1 m L,按平皿法分别用营养琼脂培养基和玫瑰红钠琼脂培养基培养,以计数细菌、霉菌和酵母菌。结果:验证所用培养基的菌落平均数均大于对照培养基上的70%,且菌落形态大小一致。稀释液对照组和试验组培养基上菌落平均数的回收率均大于70%,且菌落形态大小一致。三批维生素K1及其加速和长期稳定性样品中均未见菌落。结论:所选培养基适宜大肠埃希菌、金黄色葡萄球菌和白色念珠菌生长。且含聚山梨酯80的p H 7.0无菌氯化钠-蛋白胨缓冲液和维生素K1对所含大肠埃希菌、金黄色葡萄球菌和白色念珠菌无抑菌性。     

一株高温产粘菌株的筛选及其产胞外聚合物分析

从油井采出水中分离到一株高温产胞外聚合物的细菌MS-1,经16S rDNA基因序列分析属于芽孢杆菌属(Bacillus sp.).该菌能在60℃生长并产生胞外聚合物,其中胞外多糖含量为48.3%～54.5%.主要由甘露糖、葡萄糖、半乳糖组成,摩尔比分别是2.04:1.00:0.89.胞外聚合物中蛋白含量为37.2%～42.4%,主要由甲硫氨酸、亮氨酸、天门冬氨酸、丙氨酸、组氨酸和丝氨酸组成.利用透射电镜和环境扫描电镜对胞外聚合物的形成进行了观察.该菌的分离和研究为高温油藏的微生物调剖和驱油奠定了生物学基础.     

树舌多糖结构修饰前后CD谱比较研究

树舌多糖ＣＦ２ａ经１５ｍｍｏｌ／Ｌ１０４ｈ选择氧化,继以次氯酸氧化、得修饰树舌多糖ＣＦ２ａｍ,其结构分析表明侧链氧化率为６５％,以Ｊ－５００Ｃ圆二色性仪比较测定ＣＦ２ａ,ＣＦ２ａ一刚果红复合物及ＣＦ２ａｍ在不同ｐＨＴ的ＣＤ谱,结果表明紫外区中性多糖ＣＦ２ａ缺少结构信息,而修饰后的ＣＦ２ａｍ在ｐＨ２．０时有很强的有序结构信息,ＣＦ２ａ分子整体修饰、即其与刚果红形成复合物时,除提供很强的外源Ｃｏｔｔｏｎ效应外也提供了一些有序结构信息．     

一株芽孢杆菌的分离和鉴定

从中国农业科学院北京畜牧兽医研究所鸡舍附近土壤中分离到一株芽孢杆菌P-25,并进行了分子鉴定。通过形态鉴定、革兰氏染色、生理生化测定、16SrRNA序列分析和系统发育树构建,确定该菌株为蜡状芽孢杆菌(Bacillus cereus),其16SrRNAGenBank登录号为GU271135。     

芽胞杆菌发酵产2,3-丁二醇的研究进展及展望

综述了近年来利用芽胞杆菌生产2,3-丁二醇(2,3-BD)的研究进展,包括生产菌株的筛选、影响芽胞杆菌发酵2,3-丁二醇的因素、芽胞杆菌2,3-丁二醇代谢途径及调控等方面,并对其研究方向进行了展望。     

耐碱芽胞杆菌木聚糖酶的形成条件及特性

通过碱性选择平板分离到耐碱的芽胞杆菌B－141菌株。该菌在碱性（pH10）条件及木聚糖存在下能产生胞外木聚精酶。该酶最适反应温度为60℃,在60℃以下基本稳定;酶反应的最适pH为3～7,但在碱性条件下稳定,在pH10环境处理60min,仍保持约70％的活性。从TLC分析可知,该酶作用于燕麦木聚糖时,主要产物为大于三体的寡糖。     

Microbial control and biotechnology research on Bacillus thuringiensis in China

The current status of production and application of biopesticides for pest control in China is briefly reviewed, with a focus on research advances in microbial control with Bacillus thuringiensis (Bt). These have led to improvements in Bt production, exploitation of Bt gene resources, and development of engineered Bt insecticides and transgenic Bt crops that have expanded host ranges and increased efficacy against target pests. Both conventional and biotechnology approaches need to be employed to achieve further progress in discovery, production technology, formulation processing, development of quality standards and recommended use patterns.     

Purification and characterization of an extracellular polysaccharide from haloalkalophilic Bacillus sp. I-450

During the course of investigation of haloalkalophilic bacteria, we screened some heavily polluted soil samples from the mudflats surrounding the city of Inchon, Korea, for their bioflocculant producing ability. Based on the screening, one isolate no. 450 tentatively identified as Bacillus sp. produced an extracellular polysaccharide having flocculation activity. The isolate produced the polysaccharide during the late logarithmic growth phase. The polymer could be recovered from the supernatant of the fermented medium by cold ethanol precipitation and purified by treating with cetylpyridinium chloride (CPC). The polymer was identified as an acidic polysaccharide containing neutral sugars, namely, galactose, fructose, glucose and raffinose, and uronic acids as major and minor components, respectively. The amount of neutral sugars, uronic acid and amino sugars were 52.4, 17.2 and 2.4%, respectively. The molecular weight of the polysaccharide was found to be 2.2×10⁶ Da. The Fourier transform infrared spectrophotometer (FT-IR) revealed typical characteristics of polysaccharides. ¹H NMR spectrum showed that the polymer is a heteroglycan. Thermogravimetric (TGA) analysis indicated the degradation temperature (T_d) at 290 °C. The rheological analysis of the polymer 450 revealed the pseudoplastic property with shear-thinning effect, while the compression test indicated that the polymer had high gel strength, and the S.E.M. studies showed that the polymer has a porous structure with small pore-size distribution indicating the compactness of the polymer.