木聚糖酶高产菌株Q116诱变选育研究

以黑曲霉D8为出发菌株,采用60Coγ-射线,NTG处理等方法筛选得到黑曲霉木聚糖酶变异菌株Q116.在固体发酵试验中,酶活达到182611U/g.经过连续的传代保存,此菌株有良好的遗传稳定性,并对发酵条件进行了试验.     

生物有机肥优势发酵菌株的筛选

稀释平板法分离获得36个菌株,挑选生长优势明显、生长速度较快的菌株进行纯培养,通过原料减重法测试,筛选获得两个分解能力较强的菌株,其中菌株6四天内平均每天分解1.000g牛粪粉,在堆肥发酵中三天内达到高温期,比对照快5天,温度提高20°C。     

高产柚苷酶菌株的筛选研究

以桔皮粉为诱导底物,采用富集培养的方式从堆积腐烂桔皮的泥土中筛选出一株高产柚苷酶(Naring-inase)的生产菌株WP-108.其摇瓶发酵培养测定其酶活力达910.1 U/mL,同时其继代培养稳定性良好.通过对菌株的培养特征,形态特征的观察,初步鉴定该菌株为黑曲霉(Aspergillus niger).     

优势菌种的驯化与纯菌液相油烟降解速率

用油烟气冷凝液为碳源,驯化来自城市污水处理厂氧化沟的活性污泥,结果表明真菌增长较快并显示出优势,微生物通过分工协作降解油烟污染物.一株优势红冬胞酵母菌被分离出来进行降解液相油烟污染物的动力学试验研究,实验结果表明:在优化条件37℃、pH值范围为6.0~7.0、无机盐浓度为1.0 m g/L、磷酸氢铵浓度为5.0 m g/L、溶解氧浓度为5.4 m g/L(搅拌速度120~160 r/m in)下,优势红冬胞酵母菌降解液态油脂的动力学模型是:u=0.13s352 s(-h 1);在低油烟浓度(352 m g/L)条件下,降解反应为一级生化反应;在高油烟浓度(352 m g/L)条件下,降解反应为零级生化反应;当油烟浓度等于352 m g/L时,比降解速率是最大比降解速率K值的一半,油烟浓度处于352 m g/L附近时,是从一级降解反应到零级降解反应的过度区.     

淀粉酶产生菌的分离筛选

从大米厂、淀粉厂周边环境土壤中筛选到三株产淀粉酶能力较强的菌株Jz1、Jz2、Jz3。经形态特征及染色等初步鉴定,菌株Jz1和Jz3为芽孢杆菌属（Bacillus）,菌株Jz2为短小杆菌属（Curtobacterium）。采用YoungJ.Y00改良法测定此三株菌株的淀粉酶活力分别为47.29 U/mL、48.48 U/mL、49.74 U/mL,具有较好的应用潜力。     

Screening of benzoic acid biodegradation strains

Three strains BQ,BJ,and BS utilizing benzoic acid as the sole carbon source were achieved from Yichang City,Hubei Province,China,through selective enrichment and domestication.Both BQ and BJ were primarily identified as Acinetobacter.spp while BS was Geotrichum.spp.After three domestications,the removal rates of BQ,BJ,and BS to chemical oxygen demand(COD) value of benzoic acid were 62.41%,94.44%,and 43.34%,respectively.The strains were mixed cultured,and the degradation rates of strains to benzoic acid at different temperature,pH and benzoic acid concentration were determined.The results show that the optimum degradation conditions about strains were pH 7.0,temperature 30 ℃,and aerobic with 1 500 mg/L of concentration of benzoic acid.In this condition,the COD removal rate of strains to benzoic acid reached 84.93%.     

谷氨酸产生菌原生质体的制备和再生

6株谷氨酸产生菌以甘氨酸、青霉素和溶菌酶不同组合处理,对其原生质体形成进行了比较,在最佳条件下,原生质体形成率可达95～100％。B9-15 菌株细胞形态特殊,表面呈凹陷状,仅在含1.5～2.0％甘氨酸的高渗培养液中就能形成原生质体,在加有壁制剂的丁二酸钠高渗培养基上,所试菌株的原生质体再生率从10.5％～61.8％,差异性较大。     

高效溴氨酸脱色菌的分离鉴定及其特性研究

文章从ABR反应器污泥中筛选到1株对溴氨酸具有较好脱色作用的细菌E2,通过对这株细菌的形态观察、生理生化特征鉴定及16S rDNA序列测定,认为菌株E2是Enterobacter ludwigii。菌株E2对溴氨酸脱色的最佳碳、氮源分别为葡萄糖和硫酸铵;最适碳源质量浓度为1 g/L,质量浓度过高,脱色效果反而不显著;最适氮源质量浓度为0.5 g/L,质量浓度增大,脱色率基本不变;磷酸盐对脱色无显著影响;菌株E2对溴氨酸脱色的最佳pH值为7~8,最适温度为30~35℃,最适接种量为5%;随溴氨酸质量浓度的增加,脱色率降低,但对于400 mg/L的溴氨酸,脱色率仍可达80.5%;在所考察盐度范围内,盐度对脱色无显著影响。溴氨酸经生物脱色降解后产生一种新产物,此产物的最大吸收波长为410 nm。     

红曲霉菌株生物学特性的研究

对降脂红曲霉的生物学特性进行了研究，通过研究发现降脂红曲霉菌株具有特定的形态特征，其最适生长温度为30－35℃，孢子萌发和菌丝生长的最适pH值为4.0-5.5，菌株的耐酒精能力较高，体积分数可达15％。     

异养菌株HNR脱氮性能

从膜生物反应器中分离出一株异养型高效脱氮细菌,该菌为革兰氏阴性杆菌,命名为HNR.经16S rRNA测序,该菌株属于Acinetobactersp.菌属.以氯化铵为惟一氮源,探讨了不同碳源、pH值、温度及碳与氮质量分数之比w(C/N)对HNR菌株脱氮性能的影响.实验结果表明:以葡萄糖为碳源、pH值为8、温度为30℃、w(C/N)为10时,HNR具有最佳脱氮效果.在好氧条件下,当氨氮初始质量浓度为120 mg/L时,经过72 h的连续培养,其氨氮和总氮的去除率分别达92.5%和89.1%.通过气相色谱能检测到N2,但检测不到N2O.HNR不具有明显的好氧反硝化性能,表明HNR的脱氮途径可能与已报道过的异养硝化好氧反硝化脱氮途径有所不同.     

Protein-only transmission of three yeast prion strains

Key questions regarding the molecular nature of prions are how different prion strains can be propagated by the same protein and whether they are only protein. Here we demonstrate the protein-only nature of prion strains in a yeast model, the [PSI] genetic element that enhances the read-through of nonsense mutations in the yeast Saccharomyces cerevisiae. Infectious fibrous aggregates containing a Sup35 prion-determining amino-terminal fragment labelled with green fluorescent protein were purified from yeast harbouring distinctive prion strains. Using the infectious aggregates as 'seeds', elongated fibres were generated in vitro from the bacterially expressed labelled prion protein. De novo generation of strain-specific [PSI] infectivity was demonstrated by introducing sheared fibres into uninfected yeast hosts. The cross-sectional morphology of the elongated fibres generated in vitro was indistinguishable from that of the short yeast seeds, as visualized by electron microscopy. Electron diffraction of the long fibres showed the 4.7 A spacing characteristic of the cross-beta structure of amyloids. The fact that the amyloid fibres nucleated in vitro propagate the strain-specific infectivity of the yeast seeds implies that the heritable information of distinct prion strains must be encoded by different, self-propagating cross-beta folding patterns of the same prion protein.     

石油降解菌的分离与鉴定

按照石油污染土壤微生物修复技术目前发展的方向,本论文针对天津大港油田地区石油污染盐碱土壤的现状,经过分离、筛选、复筛,从大港油田的石油污染土壤中富集分离、优选出2株石油降解菌,并进一步研究了2株菌的生理生化特性.菌株鉴定结果表明,菌株DB-1属于假单胞杆菌属,菌株DF-1属于曲霉菌属.     

防治甜菜夜蛾的双菌株混合发酵研究

研究了蜡状芽孢杆菌Ym2102与苏云金芽孢杆菌DL5789的混合发酵.结果发现其3000倍稀释液对甜菜夜蛾的致死率为94.2%,摇瓶发酵最终菌数为2.8×109,pH变化趋缓.