To be competitive with common plastics, the production costs of polyhydroxyalkanoates (PHAs) have to be minimized. Biotechnological polymer production occurs in aerobic processes; therefore, only about 50% of the main carbon sources and even a lower percentage of the precursors used for production of co-polyesters end up in the products wanted. A second cost factor in normally phosphate-limited production processes for PHAs is the costs for complex nitrogen sources. Both cheap carbon sources and cheap nitrogen sources are available from agricultural waste and surplus materials and make a substantial contribution for minimizing PHA production costs. In this study, fermentations for PHA production were carried out in laboratory-scale bioreactors on hydrolyzed whey permeate and glycerol liquid phase from the biodiesel production using a highly osmophilic organism. Without any precursor, the organism produced a poly[3(hydroxybutyrate-co-hydroxyvalerate)] copolyester on both carbon sources. During the accumulation phases, a constant 3-hydroxyvalerate content of 8-10% was obtained at a total PHA concentration of 5.5 g/L (on hydrolyzed whey permeate) and 16.2 g/L (glycerol liquid phase). In an additional fermentation, an expensive nitrogen source was substituted by meat and bone meal beside the glycerol liquid phase as a carbon source, resulting in a final PHA concentration of 5.9 g/L.
The fraction of quaternary benzophenanthridine alkaloids from roots of Chelidonijim maiMs L., containing chelerythrine and sanguinarine, has been tested for its antiinflammatory activity. On the basis of its low toxicity, high antiinflammatory activity and antimicrobial action, it is recommended for medical use in the treatment of oral inflammatory processes.
Enzyme promiscuity is generally accepted as the ability of an enzyme to catalyse alternate chemical reactions besides the 'natural' one. In this paper peroxidases were shown to catalyse the cleavage of a C=C double bond adjacent to an aromatic moiety for selected substrates at the expense of molecular oxygen at an acidic pH. It was clearly shown that the reaction occurs due to the presence of the enzyme; furthermore, the reactivity was clearly linked to the hemin moiety of the peroxidase. Comparison of the transformations catalysed by peroxidase and by hemin chloride revealed that these two reactions proceed equally fast; additional experiments confirmed that the peptide backbone was not obligatory for the reaction and only a single functional group of the enzyme was required, namely in this case the prosthetic group (hemin). Consequently, we propose to define such a promiscuous activity as 'ostensible enzyme promiscuity'. Thus, we call an activity that is catalysed by an enzyme 'ostensible enzyme promiscuity' if the reactivity can be tracked back to a single catalytic site, which on its own can already perform the reaction equally well in the absence of the peptide backbone.
Spring wheat var. Vánek was cultivated in pots in a soil naturally contaminated with heavy metals. Experimental plants were treated with three different types of brassinosteroids (BRs; 24-epibrassinolide, 24-epicastasterone and 4154) during two different growth stages 29-31 DC (off shooting) and 59-60 DC (beginning of anthesis). Content of heavy metals (Cu, Cd, Pb and Zn) was determined using AAS method in the plant growth stages 47-49 DC (visible awns), 73-75 DC (30-50% of final grain size) and 90-92 DC (full ripeness). At the stages 47-49 DC and 73-75 DC, the content of the heavy metals was determined in the biomass of whole plants, while at the stage 90-92 DC it was determined separately in straw and grains. After the treatment of plants with BRs a decrease in heavy metals content was observed in the growth stage 73-75 DC (i.e. during the period when the plants are harvested for ensilage purposes. Likewise, a decrease of lead content in the grains by 70-74% in the plants treated at both stages 29-31 DC and 59-60 DC and by 48-70% in the plants of the third group (plants treated at stage 59-60 DC) was determined as compared with the untreated plants.
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