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41.
Biotechnology applied to mining of metals 总被引:3,自引:0,他引:3
Torma AE 《Biotechnology advances》1983,1(1):73-80
The present review describes the advances achieved during the last two years in the application of biotechnological principles in the extraction of metals from ores and minerals. Despite the fact that this branch of science is very young and many details are yet to be understood, the microbes are applied at commercial levels especially for the extraction of copper and uranium from low-grade ores. The technique is far from being developed to its full potential and it is generally recognized to be a technology of the future. The studies involved are complex and multidisciplinary in nature. 相似文献
42.
Temperature, activating metal ions, and amino-acid substitutions are known to influence the CO2/O2 specificity of the chloroplast enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase. However, an understanding of the physical basis for enzyme specificity has been elusive. We have shown that the temperature dependence of CO2/O2 specificity can be attributed to a difference between the free energies of activation for the carboxylation and oxygenation partial reactions. The reaction between the 2,3-enediolate of ribulose 1,5-bisphosphate and O2 has a higher free energy of activation than the corresponding reaction of this substrate with CO2. Thus, oxygenation is more responsive to temperature than carboxylation. We have proposed possible transition-state structures for the carboxylation and oxygenation partial reactions based upon the chemical natures of these two reactions within the active site. Electrostatic forces that stabilize the transition state of the carboxylation reaction will also inevitably stabilize the transition state of the oxygenation reaction, indicating that oxygenase activity may be unavoidable. Furthermore, the reduction in CO2/O2 specificity that is observed when activator Mg2+ is replaced by Mn2+ may be due to Mg2+ being more effective in neutralizing the negative charge of the carboxylation transition state, whereas Mn2+ is a transition-metal ion that can overcome the triplet character of O2 to promote the oxygenation reaction.Abbreviations CABP
2-carboxyarabinitol 1,5-bisphosphate
- enol-RuBP
2,3-enediolate of ribulose 1,5-bisphosphate
- Kc
Kmfor CO2
- Ko
Kmfor O2
- Rubisco
ribulose-1,5-bisphosphate carboxylase/oxygenase
- RuBP
ribulose 1,5-bisphosphate
- Vc
V
max for carboxylation
- Vo
V
max for oxygenation 相似文献
43.
本文是26篇关于丝状真菌基因表达系统的研究论文的综述,包括两部份内容。前一部分叙述1979年开始建立并迅速发展起来的丝状真菌转化系统,着重介绍丝状真菌中转化系统的构建及转化的一般特点。后一部分叙述在转化系统发展基础上产生的丝状真菌基因工程,文中列出了截至1991年9月为止报道的一些成功的实例,说明它在丝状真菌工业育种和作为外源基因产物的生产和分泌系统中的应用。 相似文献
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45.
Pengfei Li Liming Ruan Ruofan Wang Tianqi Liu Gao Song Xiaofei Gao Guohua Jiang Xiaoyan Liu 《仿生工程学报(英文版)》2021,18(6):1378-1390
Nanofibers(NFs)have been widely used in tissue engineering such as wound healing.In this work,the antibacterial ZnO quantum dots(ZnO QDs)have been incorporated into the biocompatible poly(ε-caprolactone)/collagen(PCL/Col)fibrous scaffolds for wound healing.The as-fabricated PCL-Col/ZnO fibrous scaffolds exhibited good swelling,antibacterial activity,and biodegradation behaviors,which were beneficial for the applications as a wound dressing.Moreover,the PCL-Col/ZnO fibrous scaffolds showed excellent cytocompatibility for promoting cell proliferation.The resultant PCL-Col/ZnO fibrous scaffolds containing vascular endothelial growth factor(VEGF)also exhibited promoted wound-healing effect through promoting expression of transforming growth factor-β(TGF-β)and the vascular factor(CD31)in tissues in the early stages of wound healing.This new electrospun fibrous scaffolds with wound-healing promotion and antibacterial property should be convenient for treating wound healing. 相似文献
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In enzyme engineering, the main targets for enhancing properties are enzyme activity, stereoselective specificity, stability, substrate range, and the development of unique functions. With the advent of genetic code extension technology, non-natural amino acids (nnAAs) are able to be incorporated into proteins in a site-specific or residue-specific manner, which breaks the limit of 20 natural amino acids for protein engineering. Benefitting from this approach, numerous enzymes have been engineered with nnAAs for improved properties or extended functionality. In the present review, we focus on applications and strategies for using nnAAs in enzyme engineering. Notably, approaches to computational modelling of enzymes with nnAAs are also addressed. Finally, we discuss the bottlenecks that currently need to be addressed in order to realise the broader prospects of this genetic code extension technique. 相似文献
48.
Applications of recombinant DNA technology are discussed as a backdrop for evaluation of the environmental impacts of this technology. Some of applications include using traditional biological techniques for specific purposes, including nitrogen fixation, microbial pesticides, and waste treatment. In these instances the final product lies along a continuum, beginning with an organism marginally performing its function, and ending with one that is highly specialised and very efficient in what it does. One may move along this continuum toward the ‘perfect’ microorganism by using traditional methodologies of mutagenesis and selection, recombinant DNA technology, or a combination of the two. 相似文献
49.
【目的】研究乙酸合成途径阻断及NADH氧化酶表达对于谷氨酸棒杆菌生产乙偶姻的影响。【方法】在谷氨酸棒杆菌CGF2中异源表达als SD操纵子构建乙偶姻生产菌株CGT1,考察敲除乙酸生成途径cat和pqo对乙偶姻的影响。然后引入短乳杆菌的NADH氧化酶,在优化的溶氧条件下研究其对乙偶姻产量的影响。【结果】CGT1在摇瓶发酵中可积累6.27 g/L乙偶姻,敲除cat使乙偶姻产量显著提高30.94%,达到8.21 g/L;双敲除cat和pqo没有进一步提高产量。通过优化发酵的溶氧水平,乙偶姻产量达到10.06 g/L。在高溶氧水平下引入NADH氧化酶导致菌株的生长和糖代谢速率提高,但乙偶姻产量略有降低。在分批补料发酵中,重组菌株乙偶姻产量达到40.51 g/L,产率为0.51 g/(L?h)。【结论】在谷氨酸棒杆菌中阻断乙酸合成途径cat能够有效提高乙偶姻产量,NADH氧化酶在高溶氧水平下表达不利于乙偶姻的合成,需要进一步调节表达水平以确定其效果。 相似文献
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