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化学诱变结合结构类似物法选育高苯丙氨酸解氨酶菌种 总被引:4,自引:2,他引:2
EMS诱变结合结构类似物法提高含PAL出发菌株红酵母Rhodotorula sp.CIBASA1401100 生物转化能力阳性率为35.5 % ,部分突变株PAL转化能力提高1 倍以上,其中E105,E240 具有快速转化能力,反应3 hLPhe累积浓度达到1 gL左右.φ10% 甘油和30 gLGlu 对PAL转化具有明显的稳定作用.用含φ10% 甘油和30 gLGlu 的反应液进行生物转化制备,E105 和E240 在24 h 期间LPhe 质量浓度大于20 gL,转化率达80 % . 相似文献
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An artificial soil method was applied to study the effects of perfluorooctane sulphonate (PFOS) and perfluorooctanoic acid (PFOA) on earthworms (Eisenia fetida). Survival, growth inhibition and damage to DNA of earthworms were detected after 14 d acute exposure. The 14 d-LC50 of PFOS and PFOA was 478.0?mg·kg?1 dw and 759.6?mg·kg?1 dw, respectively, indicating that they were of low toxicity. Both PFOS and PFOA could significantly inhibit the growth of earthworms after 14 d exposure, and growth inhibition rates increased with the greater concentrations of PFOS or PFOA, showing a dose–response relationship (PFOS: r?=?0.951, P .01; PFOA: r?=?0.962, P?.01). PFOS or PFOA were shown to damage earthworm coelomocytes DNA, the indicators of treatments exposed to PFOS or PFOA, tail length (TL), comet length (CL), head DNA content (HD) and olive tail moment (OTM) were significantly different (P?.05) from the control treatments, and the indicators and concentration of PFOS or PFOA had a strong dose–response relationship. 14 d-LC50 of PFOS was lower than that of PFOA, the growth inhibition rate of earthworm exposed to PFOS was higher than that exposed to PFOA at the same concentration level, and the median values of TL, CL and OTM in PFOS treatments were also higher than those in PFOA treatments. In conclusion, both these fluorine compounds were moderately toxic to earthworms, but the PFOS effect was greater than that of PFOA. 相似文献
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研究了 F- 与茜素磺酸锆的褪色反应条件 ,建立了一种负吸光度法测定微量氟化物的新方法 ,F- 量在 0~ 1 5μg/2 5 ml范围内与负吸光度值呈线性关系 ,方法已用于环境水中微量氟的测定 ,RSD为 0 .2 5 %~ 4 .2 % ( n=5 ) ,回收率为93.1 %~ 1 0 2 .0 %。 相似文献
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研究了城市污水处理系统对直链烷基苯磺酸钠(LAS)的去除特性.在厌氧-缺氧-好氧条件下,进行了相应的序批式试验,确定了水相和泥相中LAS降解的动力学参数,建立了LAS在厌氧-缺氧-好氧状态下的去除动力学模型(考虑吸附作用),并对模型预测的结果与实际测量值进行了比较.结果表明,在不同的泥龄下,LAS 在AAO系统中去除率达到99%,出水中只含微量的LAS(0~20 μg·L-1).厌氧池、缺氧池及好氧池LAS污泥吸附量分别为490~710、280~390、69~109 μg·g-1.序批式动力学降解试验还表明,厌氧去除速率系数K厌、缺氧的去除速率系数K缺与好氧的去除速率常数的比值分别为0.67和0.71,说明在同一污泥系统的厌氧和缺氧条件下,LAS也能被较好的降解.模型得到的各池混合液出水中LAS的浓度模拟结果与实测结果符合较好(误差<8%). 相似文献
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