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INTRODUCTION For the degradation of high concentration wast- ewater with toxic and non-biodegradable pollutants, the UV/Fenton method has been proposed in recent years (Braun et al., 1991; Bossmann et al., 1998). The UV/Fenton system relies mainly on oxidative degradation reactions, where organic radicals are generated by photolysis of the organic substrate or by reaction with hydroxyl radicals. These radical intermediates are subsequently trapped by dissolved molecular oxygen and lea… 相似文献
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Two-component genes are kinds of genetic elements involved in regulation of antibiotic production in Streptomyces coelicolor. DNA microarray analysis revealed that ecrA1/A2, which mapped at distant sites from red locus and encode respectively the kinase and regulator, expressed coordinately with genes of Red specific biosynthetic pathway, ecrA1 and ecrA2 gene-disruptive mutants were constructed using homogenotisation by reciprocal double crossover. Fermentation data showed that the undecylprodigiosin (Red) level of production was lower than that of wild-type strain. However, the change of the actinorhodin (Act) production level was not significant compared with wild type. Thus, these experiment results confirmed that the two-component system ecrA 1/A2 was positive regulatory element for red gene cluster. 相似文献
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研究了合成1,4-丁二磺酸二钠盐的工艺。在1,4-丁二磺酸二钠盐的合成过程中,由于在反应体系中加入表面活性剂EDTA,最佳反应时间只要约3 h,与文献[1]中长达36 h相比,大大缩短了反应时间,反应平均转化率为99.39%。建立了用高效毛细管电泳(HPCE)测定1,4-丁二磺酸的定量分析方法。分析条件为:非涂层毛细管柱为50μm×81 cm(AGILENT),缓冲液:20 mmol硼砂溶液(pH=9.24),检测波长:191.2 nm,电压进样,进样电压30 kV,进样时间5 s。对标准曲线、精密度、准确度及重现性进行了研究。该方法的线性相关系数0.999,日内变异系数0.8%,日间变异系数0.5%,回收率96.5%。HPCE法具有准确性高、重现性好、灵敏度高及快速测定的优点,非常适合于1,4-丁二磺酸二钠盐含量的测定。 相似文献
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藻蓝蛋白是红藻和蓝绿藻中一种重要的捕光色素蛋白.克隆了编码极大螺旋藻藻蓝蛋白α和β两个亚基的基因,序列分析表明该基因全长为1119bp.β亚基基因位于α亚基基因上游,两个亚基基因序列长度分别为519bp和489bp,中间被111bp的基因片段间隔.除编码α和β两个亚基的开放阅读密码框外,还存在两个潜在的开放阅读密码框,但这两个密码框的意义还不清楚.比较了该藻蓝蛋白氨基酸序列和来自于其他藻类的藻蓝蛋白氨基酸序列的同源性以及藻蓝蛋白α和β两个亚基之间氨基酸序列的同源性,总的来说其同源性在45.9%.99%之间,α和β两个亚基氨基酸序列同源性为27.1%.藻蓝蛋白包含许多疏水性氨基酸,这些疏水性氨基酸在藻胆蛋白的聚集过程中起着极为重要的作用.分析表明编码藻蓝蛋白α和β两个亚基基因的密码子显示出非对称性. 相似文献
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INTRODUCTION S.coelicolor as a model system has been ex-tensively studied with the aid of genetic and mo-lecular techniques. Its ability to produce four anti-biotics (Hopwood et al., 1995), namely actinorhodin (Act), undecylprodigiosin (Red), Calcium-Depend- ent Antibiotic (CDA) and methylenomycin (Mmy), enables studies of pathyway-specific and pleiotropic regulation of antibiotic production. In which, Red is a red-pigmented antibiotic and Act is coelicolor- pigmented antibiotic tha… 相似文献
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Study of the effect of dissolved oxygen and shear stress on rifamycin B fermentation with A. mediterranei XC 9-25 showed that rifamycin B fermentation with Amycolatoposis mediterranei XC 9-25 needs high dissolved oxygen and is not very sensitive to shearing stress. The scale-up of rifamycin B fermentation withA. mediterranei XC 9-25 from a shaking flask to a 15 L fermentor was realized by controlling the dissolved oxygen to above 25% of saturation in the fermentation process, and the potency of rifamycin B fermentation in the 15 L fermentor reached 10 g/L after 6-day batch fermentation.By continuously feeding glucose and ammonia in the fermentation process, the potency of rifamycin B fermentaion in the 15 L fermentor reached 18.67 g/L, which was 86.65% higher than that of batch fermentation. Based on the scale-up principle of constantly aerated agitation power per unit volume, the scale-up ofrifamycin B fed-batch fermentation with continuous feed from a 15 L fermentor to a 7 m3 fermentor and further to a 60 m3 fermentor was realized successfully. The potency of rifamycin B fermentation in the 7 m3 fermentor and in the 60 m3 fermentor reached 17.25 g/L and 19.11 g/L, respectively. 相似文献
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