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1.
Chemical and microbiological solubilization of silicates 总被引:1,自引:0,他引:1
S. Friedrich N. P. Platonova G. I. Karavaiko E. Stichel F. Glombitza 《Engineering in Life Science》1991,11(3):187-196
The solubilization of silicates was investigated using kaolin and quartz sand as model substances. The mineral solubilization was studied in the concentration of solubilized Si and Al. The chemical leaching of the silicates was carried out using inorganic and organic acids as well as sodium hydroxide. The process was more effective in the alkine than in the acid pH range. In the acid medium, oxalic acid showed maximum acidity and a tendency to form complex structures, especially with aluminium, and was most effective in leaching. The microbiological influence on solubilization reactions was tested using a number of microorganisms among them acid, alkali and slime-forming species. The highest leaching activity was observed in the case of Thiobacillus thiooxidans, whereas the heterotrophic microorganisms (among them Bacillus mucilaginosus) did not exercise a sollubilizing effect on the silicates. X-ray phase analysis of leached kaolin samples did not show any differences from the non-leached mineral. 相似文献
2.
G. K. Haverkamp H. Ranke C. G. Friedrich 《Applied microbiology and biotechnology》1995,44(3-4):514-518
The hydrogen-evolving reaction of the purified soluble NAD-linked hydrogenase of Alcaligenes eutrophus was used to determine kinetic parameters of the enzyme. The H2-evolving activity with methyl viologen as electron mediator was 20-fold as compared to that with NADH. In the assay with dithionite-reduced methyl viologen (K
m 0.7 mM) the hydrogenase was most active at a redox potential of –560 mV and exhibited a pH optimum of 7.0. The K
m for protons, the second substrate for H2 evolution, was 6.2 nM. With electrochemically reduced methyl viologen the pH optimum was shifted to pH 6.0. Double-reciprocal plots of reaction rates versus proton concentrations intercepted at the ordinate for different methyl viologen concentrations. At different pH values such an intercept was also observed with the dye as the varied substrate. The kinetic data are diagnostic for an ordered bisubstrate mechanism where both substrates are bound before the product H2 is released. Hydrogenase coupled to thylakoid membranes resulted in a constant H2 evolution rate over 6 h. The system appeared to be limited by the capacity of the thylakoid membranes. 相似文献
3.
Nathan D. Mathewson Orr Ashenberg Itay Tirosh Simon Gritsch Elizabeth M. Perez Sascha Marx Livnat Jerby-Arnon Rony Chanoch-Myers Toshiro Hara Alyssa R. Richman Yoshinaga Ito Jason Pyrdol Mirco Friedrich Kathrin Schumann Michael J. Poitras Prafulla C. Gokhale L. Nicolas Gonzalez Castro Marni E. Shore Kai W. Wucherpfennig 《Cell》2021,184(5):1281-1298.e26
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Friedrich Veselsky 《Plant Systematics and Evolution》1856,6(16):121-122
Ohne Zusammenfassung 相似文献
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Friedrich Ehrendorfer 《Plant Systematics and Evolution》1953,100(3):670-672
Ohne Zusammenfassung 相似文献
9.
Two hitherto unknown vitamin B-12 factors were isolated from sewage sludge. They were degraded with cerous hydroxide to cobinamide and the corresponding nucleoside. The nucleosides were further split with dilute hydrochloric acid to the bases and D-ribose. The structure of the two bases was found to be 2-methylsulfinyladenine and 2-methylsulfonyladenine. This was revealed by mass, infrared and nuclear magnetic resonance spectroscopy, and by comparison with the synthetic compounds. On addition of the synthetic bases to fermentations with Propionibacterium acidi-propionici the vitamin B-12 factors containing the corresponding base were formed. They were identical with the 2-methylsulfonyladenylcobamide and 2-methylsulfonyladenylcobamide originally isolated from sewage sludge. 相似文献
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