Hydrogen peroxide was encapsulated into a silica xerogel matrix by the sol-gel technique. The composite was tested as an oxidizing agent both under conventional and microwave conditions in a few model reactions: Noyori's method of octanal and 2-octanol oxidation and cycloctene epoxidation in a 1,1,1-trifluoroethanol/Na2WO4 system. The results were compared with yields obtained for reactions wit...

bioleaching is the extraction of metals from their ores through the use of microorganisms. inthis process, the use of native bacteria leads to achieve more yields of metals. so, in the presentstudy, native sulfur-oxidizing bacterium in potentiality of uranium extraction was isolated fromghachin mine in iran and identified by partial gene sequencing. for this purpose, the watersamples were colle...

The term biomining have been coined to refer to the use of microorganisms in mining processes as in the biooxidation of refractory gold minerals. The biooxidation of refractory gold ores presents similar characteristics when compared with roasting and pressure oxidation. Almost without exception, microbial extraction procedures are more environmentally friendly. The isolated bacteria in this st...

The term biomining have been coined to refer to the use of microorganisms in mining processes as in the biooxidation of refractory gold minerals. The biooxidation of refractory gold ores presents similar characteristics when compared with roasting and pressure oxidation. Almost without exception, microbial extraction procedures are more environmentally friendly. The isolated bacteria in this st...

Bioleaching is the extraction of metals from their ores through the use of microorganisms. Inthis process, the use of native bacteria leads to achieve more yields of metals. So, in the presentstudy, native sulfur-oxidizing bacterium in potentiality of uranium extraction was isolated fromGhachin mine in Iran and identified by partial gene sequencing. For this purpose, the watersamples were colle...

Oxidation of nitrite to nitrate in aquaria is typically attributed to bacteria belonging to the genus Nitrobacter which are members of the alpha subdivision of the class Proteobacteria. In order to identify bacteria responsible for nitrite oxidation in aquaria, clone libraries of rRNA genes were developed from biofilms of several freshwater aquaria. Analysis of the rDNA libraries, along with re...

Winogradsky discovered in 1890 that nitrification is carried out in two consecutive steps by two distinct groups of bacteria: ammonia-oxidizing bacteria and nitrite-oxidizing bacteria. An explanation for this division of labour is offered based on the kinetic theory of optimal design of metabolic pathways, which postulates the existence of an optimal length for a pathway that maximizes the rate...

the term biomining have been coined to refer to the use of microorganisms in mining processes as in the biooxidation of refractory gold minerals. the biooxidation of refractory gold ores presents similar characteristics when compared with roasting and pressure oxidation. almost without exception, microbial extraction procedures are more environmentally friendly. the isolated bacteria in this st...