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2015
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vol. 62
|
issue 1
23-34
EN
In the face of shortage of fossil fuel supplies and climate warming triggered by excessive carbon dioxide emission, alternative resources for chemical industry have gained considerable attention. Renewable resources and their derivatives are of particular interest. Glycerol, which constitutes one of the by-products during biodiesel production, is such a substrate. Thus, generated excess glycerol may become an environmental problem, since it cannot be disposed of in the environment. The most promising products obtained from glycerol are polyols, including 1,3-propanediol, an important substrate in the production of synthetic materials, e.g. polyurethanes, unsaturated polyesters, and epoxy resins. Glycerol can be used as a carbon and energy source for microbial growth in industrial microbiology to produce 1,3-propanediol. This paper is a review of metabolic pathways of native producers and E. coli with the acquired ability to produce the diol via genetic manipulations. Culture conditions during 1,3-PDO production and genetic modifications of E. coli used in order to increase efficiency of glycerol bioconversion are also described in this paper.
PL
Istnieje wiele chorób człowieka, które mogą doprowadzić do niewydolności narządów. Konsekwencją często jest konieczność przeprowadzenia przeszczepu. Liczba wykonywanych operacji jest bardzo niska ze względu na niedobór narządów do transplantacji. W konsekwencji liczba osób oczekujących na przeszczep ciągle rośnie. Wyjściem z tej sytuacji może być ksenotransplantacja. Pojęcie ksenotransplantacja pochodzi od greckiego xenos oznaczającego obcy, inny. Jest to każdy zabieg polegający na transplantacji, implantacji lub infuzji biorcy – człowiekowi – komórek, tkanek lub organów odzwierzęcych, również płynów ustrojowych, komórek, tkanek, narządów człowieka (lub ich fragmentów), które miały kontakt ex vivo z komórkami, tkankami lub organami zwierzęcymi. Jedną z przeszkód w przeszczepach ksenogenicznych jest zagrożenie przeniesienia patogenów zwierzęcych i zainfekowanie organizmu człowieka. Wirusami, które stanowią zagrożenie w przeszczepach, w układzie małpy naczelne-człowiek to między innymi: ludzki wirus upośledzenia odporności HIV (z ang. human immunodeficiency virus) i wirus Marburg, które zostały opisane w niniejszej pracy. Ponadto przedstawiono wirusy stanowiące problem w transplantacjach w układzie świnia-człowiek, czyli: endogennego retrowirusa PERV (z ang. porcine endogenous retrovirus), wirusa cytomegalii świni PCMV (z ang. porcine cytomegalovirus), wirusa limfotroficznego świni PLHV (z ang. porcine lymphotropic herpesvirus) oraz wirusa zapalenia wątroby typu E - HEV (z ang. hepatitis E virus). Niniejszy przegląd literatury stanowi najnowszy stan wiedzy na temat mikrobiologicznego bezpieczeństwa ksenotransplantacji.
EN
There are a number of human diseases, which can lead to organ failure. The consequence is often the need for a transplant. The number of performed operations is very low due to the shortage of organs for transplantation. As a consequence, the number of people waiting for transplant is still growing. The solution to this situation may be xenotransplantation. Xenotransplantation word comes from the Greek xenos meaning stranger, the other. It is defined as any procedure that involves the transplantation, implantation or infusion of tissues or zoonotic organs into a human recipient, but also human body fluids, cells, tissues, organs (or fragments) that have ex vivo contact with zoonotic cells, tissues or organs. One of the obstacles of the xenograft transplantation is the risk of animal pathogens transmission to the humans. Viruses that pose risk in the non-human primates-to-human xenotransplantation includes: the human immunodeficiency virus - HIV and the Marburg virus described in this paper. In addition viruses, which is a problem in pig-to-human xenotransplantation have also been described, including: porcine endogenous retrovirus - PERV, porcine cytomegalovirus - PCMV, porcine lymphotropic herpesvirus - PLHV and hepatitis E virus - E - HEV. This review of literature is the latest knowledge of the microbiological safety of xenotransplantation.
EN
Compared with chemical synthesis, fermentation has the advantage of mass production at low cost, and has been used in the production of various industrial chemicals. As a valuable organic compound, 1,3-propanediol (1,3-PDO) has numerous applications in the production of polymers, lubricants, cosmetics and medicines. Here, conversion of glycerol (a renewable substrate and waste from biodiesel production) to 1,3-PDO by E. coli bacterial strain carrying altered glycerol metabolic pathway was investigated. Two gene constructs containing the 1,3-PDO operon from Citrobacter freundii (pCF1 and pCF2) were used to transform the bacteria. The pCF1 gene expression construct contained dhaBCE genes encoding the three subunits of glycerol dehydratase, dhaF encoding the large subunit of the glycerol dehydratase reactivation factor and dhaG encoding the small subunit of the glycerol dehydratase reactivating factor. The pCF2 gene expression construct contained the dhaT gene encoding the 1,3-propanediol dehydrogenase. Expression of the genes cloned in the above constructs was under regulation of the T7lac promoter. RT-PCR, SDS-PAGE analyses and functional tests confirmed that 1,3-PDO synthesis pathway genes were expressed at the RNA and protein levels, and worked flawlessly in the heterologous host. In a batch flask culture, in a short time applied just to identify the 1,3-PDO in a preliminary study, the recombinant E. coli bacteria produced 1.53 g/L of 1,3-PDO, using 21.2 g/L of glycerol in 72 h. In the Sartorius Biostat B Plus reactor, they produced 11.7 g/L of 1,3-PDO using 24.2 g/L of glycerol, attaining an efficiency of 0.58 [mol1,3-PDO/molglycerol].
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