National Repository of Grey Literature 27 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Structure and biocatalytic properties of nitrilases from filamentous fungi
Křenková, Alena ; Martínková, Ludmila (advisor) ; Macek, Tomáš (referee) ; Klempier, Norbert (referee)
Filamentous fungi are alongside bacteria a rich source of nitrilases that can be used for biotechnological purposes. There is a large number of sequences of putative nitrilases in databases, but few of these enzymes have been expressed, purified and characterized. According to the sequences in GenBank database, synthetic genes of putative nitrilases from Aspergillus niger CBS 513.88 and Neurospora crassa OR74A were designed, expressed in Escherichia coli and the nitrilases produced were purified and characterized. The effect of chaperone-assisted nitrilase expression was also examined using a set of commercial chaperone plasmids. The structural properties of nitrilases were examined using various methods, such as homology modelling, sedimentation velocity analysis or electron microscopy. Recombinant nitrilase production was compared to their production by native producers - filamentous fungi. The cultivation of native producers was rather difficult and nitrilase production was very low, therefore, the advantage of using prokaryotic expression system was highlighted. Nitrilases with amino acids close to the catalytic cysteine replaced were prepared in order to study the effects of certain amino acids on the activity, chemoselectivity and enantioselectivity of nitrilases. The catalytic properties of...
Enzymatic detoxification of cyanide using cyanide hydratases
Sedova, Anastasia ; Rucká, Lenka ; Glozlová, Michaela ; Novotný, Petr ; Martínková, Ludmila ; Bojarová, Pavla
Cyanide, a strong chelator of metals in vital enzymes and proteins, is very toxic for most living organisms. Wastewaters from the mining, metallurgical and chemical industries contain significant concentrations of free cyanide. Though it can be largely eliminated by physicochemical methods, these processes may in turn lead to the formation of other waste. In addition, no effective methods have been found to neutralize cyanide spills coming from industrial accidents. The use of enzymes to remove cyanide is an attractive alternative, which is environmentally friendly and applicable to high cyanide concentrations. Cyanide hydratases (CynHs) are of considerable interest for the decomposition of hazardous cyanide wastes. Here we investigate the biochemical properties of new CynHs from Stereum hirsutum and Exidia glandulosa, it is of fundamental importance to preserve the enzyme activity at alkaline pH as cyanide waste is stored under these conditions.
Responses of Rhodococcus strains to heavy metal stress
Volf, Jan ; Štěpánek, Václav (advisor) ; Martínková, Ludmila (referee)
Increasing heavy metal pollution can be dealt with not only through physical and chemical decontamination processes but also utilizing microbial bioremediation, a much more environmentally friendly way. Members of genus Rhodococcus are suitable candidates for effective bioremediations of heavy metals due to their considerable adaptability and extreme resistance to different stress conditions, including those related to presence of heavy metals or their toxic compounds. Individual rhodococcal strains are more resistant to heavy metals than most of other microorganisms and they are capable of biotransformating them to less toxic forms or at least of accumulating effectively or adsorbing them on produced polysaccharides and specific surface active substances. Their bioremediation potential is very high even though, so far, only molecular mechanisms of rhodococcal resistances to toxic arsenic compounds have been studied more in detail.
Activities of oxidative enzymes in edible fungi of division Basidiomycota and their bioremediation potential
Smidová, Tatiana ; Martínková, Ludmila (advisor) ; Gabriel, Jiří (referee)
The topic of the thesis is the potential use of fungi of the phylum Basidiomycota for bioremediation. Various species of this phylum contain enzymes such as laccase or tyrosinase that can be useful for the environment management. The residual substrate after fungi cultivation can be an efficient source of these enzymes. New methods of enzymes extraction could lower the costs of their usage for bioremediation as well as increase their availability for the commercial use.

National Repository of Grey Literature : 27 records found   1 - 10nextend  jump to record:
See also: similar author names
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13 Martínková, Lenka
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