物理诱变处理氧化亚铁硫杆菌的育种研究

以氧化亚铁硫杆菌作为出发菌,采用物理诱变进行处理。研究结果表明,经过微波和超声波诱变均能加快氧化亚铁硫杆菌氧化Fe2+和转化SO32-的速度。尤其是经过90 s微波处理的氧化亚铁硫杆菌进入对数期的时间比未经诱变前缩短12 h,48 h时Fe2+的氧化率达到99%,4小时后SO32-基本全部转化为SO42-。     

Biodegradation of Crystal Violet by Agrobacterium radiobacter

Agrobacterium radiobacter MTCC 8161 completely decolorized the Crystal Violet with 8 hr (10 mg/L) at static anoxic conditions. The decreased decolorization capability by A. radiobacter was observed, when the Crystal Violet concentration was increased from 10 to 100 mg/L. Semi-synthetic medium containing 1% yeast extract and 0.1% NH4Cl has shown 100% decolorization of Crystal Violet within 5 hr. A complete degradation of Crystal Violet by A. radiobacter was observed up to 7 cycles of repeated addition (10 mg/L). When the effect of increasing inoculum concentration on decolorization of Crystal Violet (100 mg/L) was studied, maximum decolorization was observed with 15% inoculum concentration. A significant increase in the activities of laccase (184%) and aminopyrine N-demethylase (300%) in cells obtained after decolorization indicated the involvement of these enzymes in decolorization process. The intermediates formed during the degradation of Crystal Violet were analyzed by gas chromatography and mass spectroscopy (GC/MS). It was detected the presence of N,N,N′,N′′-tetramethylpararosaniline, [N; N-dimethylaminophenyl] [N-methylaminophenyl] benzophenone, N; N-dimethylaminobenzaldehyde, 4-methyl amino phenol and phenol. We proposed the hypothetical metabolic pathway of Crystal Violet biodegradation by A. radiobacter. Phytotoxicity and microbial toxicity study showed that Crystal Violet biodegradation metabolites were less toxic to bacteria (A. radiobacter, P. aurugenosa and A. vinelandii) contributing to soil fertility and for four kinds of plants (Sorghum bicolor, Vigna radiata, Lens culinaris and Triticum aestivum) which are most sensitive, fast growing and commonly used in Indian agriculture.     

Application of waste frying oils in the biosynthesis of biodemulsifier by a demulsifying strain Alcaligenes sp. S-XJ-1

Exploration of biodemulsifiers has become a new research aspect. Using waste frying oils (WFOs) as carbon source to synthesize biodemulsifiers has a potential prospect to decrease production cost and to improve the application of biodemulsifiers in the oilfield. In this study, a demulsifying strain, Alcaligenes sp. S-XJ-1, was investigated to synthesize a biodemulsifier using waste frying oils as carbon source. It was found that the increase of initial pH of culture medium could increase the biodemulsifier yield but decrease the demulsification ratio compared to that using paraffin as carbon source. In addition, a biodemulsifier produced by waste frying oils and paraffin as mixed carbon source had a lower demulsification capability compared with that produced by paraffin or waste frying oil as sole carbon source. Fed-batch fermentation of biodemulsifier using waste frying oils as supplementary carbon source was found to be a suitable method. Mechanism of waste frying oils utilization was studied by using tripalmitin, olein and tristearin as sole carbon sources to synthesize biodemulsifier. The results showed saturated long-chain fatty acid was difficult for S-XJ-1 to utilize but could effectively enhance the demulsification ability of the produced biodemulsifier. Moreover, FT-IR result showed that the demulsification capability of biodemulsifiers was associated with the content of C=O group and nitrogen element.     

苏云金芽孢杆菌BtZ01对小鼠胚胎和胚后发育的影响

为了探讨苏云金芽孢杆菌(Bacillus thuringiensis,Bt)Bt Z01对小鼠胚胎发育和胚后生长发育的影响,将48只孕鼠随机分组,试验组饲喂浓度分别为106CFU·m L-1、108CFU·m L-1、5×109CFU·m L-1的Bt Z01菌液,并设灭菌水为对照组。采用行为致畸学方法检查Bt Z01对小鼠胚胎和胚后发育的影响并制作脏器切片,测量脏器指数等指标。结果表明,与对照组相比,各试验组小鼠在胚胎和胚后发育各阶段体重和体长无显著差异(P0.05),胚胎畸形发生率无增加,骨骼染色观察发现高剂量组小鼠后囟门显著大于其他3组(P0.05)。18 d与48 d小鼠部分脏器指数存在显著差异,但病理切片观察发现仅高剂量组肾脏有病变发生。试验结果表明,苏云金芽孢杆菌Bt Z01在浓度为108CFU·m L-1及以下时对小鼠胚胎发育及胚后生长发育无不良影响。     

枯草芽孢杆菌液体生物被膜形成中对镉离子耐受性研究

生物膜法被广泛用于污水处理领域,而污水中含有的重金属离子会严重影响生物被膜的稳定性,降低污水处理效率。该研究以污水处理系统中常见的枯草芽孢杆菌(Bacillus subtilis)为研究对象,分析了菌体在液体生物被膜形成过程中对镉离子的耐受性。结果表明,枯草芽孢杆菌胞外基质合成的抑制因子Sin R缺失后,突变株耐受Cd2+离子的能力明显增强,说明胞外基质能够提高菌体对Cd2+的耐受性;△eps G突变株比△tas A突变株对Cd2+更敏感,说明胞外多糖比胞外蛋白起到更显著的保护作用;同时发现△eps G突变株和△tas A突变株可以共享分别产生的胞外蛋白和多糖;该研究还首次发现硬水软化剂EDTA-2Na能够提高菌株形成生物被膜过程中对Cd2+的耐受性。该研究对于提高污水处理系统中生物被膜的初始驯化速度和生物被膜稳定性具有一定的理论指导和实践意义。     

降解园林废弃物专用固体复合菌的构建及其堆肥效应研究

目前应用于园林废弃物堆肥中的复合菌剂大多为液态菌剂,其制作存在无菌操作要求高、产品存在运输不便等问题,拟尝试通过固体菌剂加以克服.为获得可高效降解园林废弃物的固体复合菌剂,利用前期获得的固体菌剂芽孢杆菌（Bacillus sp.）B01和B02进行混配制成复合菌剂,通过正交试验对复合比例（B01:B02）及复合菌剂接种浓度进行优化,筛选出降解效果最佳的固体复合菌剂SB012,并与其液体复合菌剂LB012进行对比,探究二者对园林废弃物堆肥过程的影响.结果表明:各因素对固体复合菌剂应用效果均有极显著影响,其影响程度表现为复合比例>复合菌剂接种浓度;最佳固体复合菌剂是复合比例（B01:B02）为7.5:2.5,复合菌剂接种浓度为2.5%.与LB012相比,SB012可使木质素降解率提高7.79%,纤维素降解率提高5.30%,腐殖质含量提高6.29%,腐殖化系数（HI）提高23.02%.研究显示,通过对复合比例和复合菌剂接种浓度的优化,成功制得固体复合菌剂SB012,该菌剂可高效降解园林废弃物中的木质素、纤维素,促进腐殖质生成,提高堆肥产品品质.      

硝基芳香烃降解菌株的分离、鉴定和应用

从被二硝基甲苯(DNT)和三硝基甲苯(TNT)污染的土壤中分离到5个高效降解硝基芳香烃类化合物的菌株TD1、TD2、TD3、TD4和TD5。16S rDNA序列分析表明,TD1、TD2、TD3和TD4属于节杆菌属(Arthrobacter),TD5属于不动杆菌属(Acinetobacter)。菌株复配试验表明,TD1、TD2、TD3、TD4和TD5的体积比例为2:2:2:1:1时对含有DNT和TNT的炸药废水的CODC r去除率最好。最佳复配的菌液投加到装有合适填料载体的生物反应器中用于处理炸药废水,运行47d后出水CODC r不超过200 mg/L,硝基苯类化合物的浓度在2 mg/L以下。     

重金属生物吸附研究中蜡状芽孢杆菌菌体微观形貌的原子力显微镜观察与表征

对蜡状芽孢杆菌在重金属生物吸附条件下细胞的界面形态及其变化情况进行了原子力显微镜成像观察与表征 .结果表明 ,在严格实验对照条件下未加入Pb(II)的空白菌体细胞呈杆状 ,单个细胞长约 3 3μm ,横截面分析结果为宽 1 9μm左右 ,高为 0 3～ 0 4 μm ,细胞壁表面比较光滑 ,细胞之间以竹节结构首尾相连排列成长杆状 ;吸附Pb(II)后细胞的体积则发生膨胀 ,单个细胞长约 3 9μm ,横截面分析结果为宽 3 1 μm左右 ,高约为 1 1 5 μm ,细胞壁表面变得比较粗糙 ,细胞之间较容易发生粘结 ,与对照空白菌体相比 ,细胞之间呈长杆状的竹节结构排列则变得很少 .采用截面分析曲线中形貌特征的高宽度比R对细菌细胞在云母基底表面的横向铺展变形作用进行了定量表征 (吸附铅离子后R值由 0 1 6 5变为 0 4 1 6 ) ,同时探讨了细胞在基底表面的横向铺展变形作用可能与细胞表面电荷影响细胞在基底表面的粘附性能密切相关 ,并受溶液pH、离子强度以及金属离子的暴露与吸附等外界因素影响而发生改变 .有关其详细机理 ,还有待在以后的研究工作中作进一步探讨     

降解亚硝酸盐菌株的分离与脱氮能力研究

文章从鳗鲡肠道中筛选出一株具备高效降解亚硝酸盐与硝酸盐和安全的优良芽孢杆菌B1,经过16S rRNA序列分析与生理生化检测,鉴定为地衣芽孢杆菌(Baclicus lincheniformis)。该菌株在葡萄糖10 g/L、28℃好氧条件下培养24 h,亚硝酸盐由85.61 mg/L降低至0.47 mg/L,降解率99.45%;硝酸盐由96.12 mg/L降低至1.04 mg/L,降解率98.92%;氨氮由52.74 mg/L降至18.71 mg/L,降解率64.52%。在模拟处理养殖水体,接种终浓度为10~6CFU/mL菌株B1后,3 d亚硝酸盐浓度由5.15 mg/L降低至0.41 mg/L,降解率达92.04%,5 d降低至0.09 mg/L,达到养殖水体标准;鳗鲡在含菌株B1终浓度为10~8CFU/mL水体中,15 d无明显病理变化。试验结果说明:鳗鲡肠道原籍菌株B1具有高效的硝化与好氧反硝化能力,对水产养殖动物安全、无副作用。研究结果表明,菌株B1有助于水产养殖水体的生物脱氮或含高浓度氮的废水处理,具有良好的微生态开发应用前景。     

微生物处理含SO2气体的试验研究

介绍一种氧化亚铁硫杆菌脱除SO2的新工艺。并研究铁离子浓度、液气比和气体SO2浓度等对脱硫效率的影响。对比实验表明细菌菌液比稀硫酸吸收法的脱硫效率更高。在细菌菌液的脱硫作用中，不仅铁离子，而且细菌本身也起到了关键作用。实验结果表明利用微生物脱除气体中的SO2是一个可行的技术方案。