The aim of the paper was to estimate the applicability of continuous sterilizationto the improvement of bacitracin production technology. Preliminary investigations were carried out and the effects of application of thermal continuous sterilization of substrates were estimated. The quality of sterilized substrates was assessed in fermentation tests. Bacitracin biosynthesis was carried out on a substrate sterilized by both batch and continuous method. In laboratory investigations a substrate sterilized by the continuous method enabled to increase antibiotic production by 30% on the average as compared to the yield obtained using a batch sterilized substrate. On an industrial scale, for the same inoculation material the production was even higher by 80%.
The effect of batch and continuous thermal treatment on the rheological properties of a protein-carbohydrate preparation made from soya flour (a basic component of many fermentation media) was described. Flow curves were determined using the Brabender Rheotron rotation rheometer for shear rates 20 ? 600 s-1 at soya flour concentration equal to 5 and 10%. The dependence of the suspension Newtonian viscosity on the temperature and time was described by empirical formulan. An interpretation of the results was proposed on the basis of hydration and dehydration of protein-starch structures of the preparation and the degradation of protein and carbohydrates caused by high temperature.
For the first time, high pressure was used for milk sterilization at the beginning of this century. However, only recently attention has been paid to this method and its possible applications in food preservation and inactivation of some viruses. In this review, we summarize high pressure effects on biological macromolecules such as proteins, nucleic acids, ribosomes and other cell components. We also show examples of practical application of high pressure in food conservation and medicine.
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The ?protein only? hypothesis holds that the infectious agent causing transmissible spongiform encephalopathies is a conformational isomer of PrP, a host protein predominantly expressed in brain and is strongly supported by many lines of evidence. Prion diseases are so far unique among conformational diseases in that they are transmissible, not only experimentally but also by natural routes, mainly by ingestion. The pathway of prions to the brain has been elucidated in outline. A striking feature of prions is their extraordinary resistance to conventional sterilisation procedures, and their capacity to bind to surfaces of metal and plastic without losing infectivity. This property, first observed in a clinical setting, is now being investigated in experimental settings, both in animals and in cell culture.
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