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1.
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   
2.
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   
3.
单宁对杨梅汁花色苷稳定性的影响   总被引:16,自引:0,他引:16  
分析了单宁对增加杨梅汁花色苷稳定性的效果。在pH=4.5和pH=3.2时加入单宁使杨梅汁最大吸收波长和最大吸光度增大。在pH为1.0时单宁浓度增大导致杨梅汁最大吸收波长增大,但最大吸光度没有增加。单宁和杨梅汁花色苷的辅助色素反应为放热反应,其△H等于-8.481kJ/mol, △S为7.286J/mol。温度的升高促进辅助色素反应向分解方向进行。  相似文献   
4.
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   
5.
于平  岑沛霖  励建荣  秦松 《科技通报》2003,19(6):457-460
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   
6.
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   
7.
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   
8.
杨梅汁内花色苷热降解动力学研究   总被引:20,自引:0,他引:20  
对杨梅汁内花色苷的热稳定性进行了研究。结果表明,充氮条件下,pH为1.0、3.2、4.5的热降解活化能(E0)分别为386.902、317.837和283.028kJ/mol。在有氧条件下相应的E0分别为343.464、290.970和258.251kJ/mol。说明充氧处理可以明显提高杨梅汁内花色苷的稳定性,同时也可看出,不管是在有氧还是充氮条件下,随着pH值的增高,E0值变小,说明低值下花色苷的热稳定性较好。  相似文献   
9.
近年来随着螺旋藻研究的深入及分子生物学的渗透,有关螺旋藻基因工程的研究迅速发展并取得了较满意的成果。本文全面综述了这些研究成虹并提出了今后螺旋藻基因工程研究发展的方向;通过重组DNA技术构建螺旋藻新品种和实现螺旋藻天然产物基因工程生产。  相似文献   
10.
于平  岑沛霖  励建荣  张燕萍  秦松 《科技通报》2004,20(1):21-23,27
通过PCR技术克隆了极大螺旋藻藻蓝蛋白基因,构建了克隆载体和表达载体,并将该基因导入巴斯德毕赤酵母X-33基因组,筛选了能够有效表达藻蓝蛋白基因的毕赤酵母工程菌株PC8,从而为发酵法生产藻蓝蛋白奠定了基础。  相似文献   
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