Case studies of environmental impact assessment were performed for production steps of three traditional food production lines (dairy cow breeding, dry-cured ham, Brassica sp. growing) in order to ...examine the previously constructed methodological framework. The emission inventory was obtained on the basis of initial experimental data. The emissions were aggregated accordingly for the characterization to environmental impact categories. The contribution of studied process steps to several environmental impact categories was assessed (greenhouse gas emission, acidification potential, eutrophication potential, use of resources and use of agricultural land).
In order to improve the knowledge on environmental impacts of current production systems and to find the solutions to reduce the negative impacts effective multi-approach environmental assessment ...methodologies are required. The environmental impacts assessed in complex systems, such as agriculture and food production, are prone to higher uncertainties. Therefore, field-specific standardization of the assessment procedures based on multiple screening studies are required to make the assessment outcome less vulnerable. The procedure array pairing for the formation of production step emission inventory is an important methodological process in environmental impact assessment. Initial production data was coupled with specialized databases, models found in scientific literature and environmental category characterization guidelines in order to construct an environmental impact methodological framework specific to four case studies of traditional food production.
A successful biogas production process depends upon adequate hydrolysis of macromolecules in the substrate and stable further conversion. The complex and rigid structure of cellulosic, hemicellulosic ...and lignin chain is preventing lignocellulosic biomass to reach efficient hydrolysis, therefore pretreatment of a substrate is needed for higher biogas and methane yields. There are several different physical and chemical methods of pretreatments available which include the usage of acids, alkalis, organic solvents, ionic detergents, steam, high pressure, grinding, ultrasound, and microwave irradiation. Physico-chemical pretreatments act rapidly on lignocellulose but their upscaling is very expensive in industry. Many studies have been made in finding the best combination of different pretreatment methods and also new biological techniques which could make lignocellulose pretreatment cheaper and environmentally more friendly. Using natural abilities of different fungi, bacteria or yeast to degrade lignocellulose simplifies the whole process. Also cocktails of biotechnologically produced enzymes are effective in degrading lignocellulose.
A screening strategy for evaluation of genotoxic potential of drinking water has been proposed in the present work. Genotoxicity assays with tap water collected at three different sampling points in ...Ljubljana drinking water region are presented here. In vitro alkaline version of the comet assay was performed with human HepG2 and Caco2 cell lines and protozoa (Tetrahymena thermophila) cells. Parallel genotoxicity evaluation on the same samples was carried out by the Ames test (with/without exogenous metabolic activation) using Salmonella typhimurium TA97a, TA100 and TA1535 strains. Nonconcentrated and concentrated water samples were tested in both bioassays, and chemical analyses were performed to check the contents of pesticides and nitrates. There was no indication of genotoxic activity in any of the drinking water samples according to the Ames test. The results of the comet assays showed differences and possible genotoxic potential among the water samples tested on different cell types, which were, however, statistically not significant, except in two cases. Statistical analyses showed the comet assay was more sensitive than the Ames test for genotoxicity detection in drinking water samples.
A bacterial model system (Pseudomonas putida DSM 50026) was used in this research to assess toxicity of the environmentally relevant concentrations of mercury species (MeHg and Hg(II)) that represent ...important pollutants of aquatic ecosystems at sites of industrial or mining activities. In addition to direct monitoring of bacterial growth, we also analyzed fatty acid profiles of exposed and non-exposed cultures to determine possible toxic effects manifested on membrane level. The results showed that exposure of P. putida to Hg(II) in concentrations of 0.2–200 µg/L did not have any significant effects on growth nor fatty acid composition of exposed bacterial culture. On the other hand, when bacteria were exposed to up to 1600-times lower concentrations of MeHg (0.12–12.5 µg/L), growth inhibition as well as significant changes in fatty acid composition were detected. Observed adaptive membrane changes due to MeHg exposure were similar to those associated with responses to organic solvents and some other membrane-disrupting compounds.
V Sloveniji postaja problematika komunalnih odpadkov vedno bolj aktualna, saj je ravnanje z odpadki eno najslabše rešenih nalog v okviru varstva okolja. Odlaganje na deponije je trenutno najbolj ...običajna praksa ravnanja s komunalnimi odpadki. Posledica neprimernega ravnanja z odpadki je tudi prekomerno sproščanje metana iz odlagališč, zato bo potrebno poiskati primernejše rešitve. V tej raziskavi smo ugotavljali, kakšna je potencialna produkcija metana iz organskih komunalnih odpadkov glede na njihovo različno granulacijo (delci različnih velikosti: >100 mm, 40–100 mm, 10–40 mm in <10 mm). Vzorcem smo predhodno določili delež organske snovi (OS), suho snov (SS), skupni organski ogljik (TOC), dušik po Kjeldahlu (TKN), NH4+ in C/N razmerje. Pred inkubacijo in po njej smo določili kemijsko potrebo po kisiku (KPK). Iz podatkov, pridobljenih v testu biokemijskega metanskega potenciala (BMP), smo izračunali naslednje parametre: kumulativno produkcijo metana, metanski potencial in izplen metana. Izkazalo se je, da velikost delcev pomembno vpliva na metanski potencial organskih komunalnih odpadkov in da bo le-te pred presnovo v bioplin potrebno zdrobiti.
One of the main mechanisms of nanoparticle toxicity is known to be the generation of reactive oxygen species (ROS) which primarily damage cell membranes. However, very limited data on membrane ...effects in anaerobic environments (where ROS could not be the cause of membrane damage) are available. In the following study, rumen anaerobe Ruminococcus flavefaciens 007C was used as a bacterial model to assess the potential effects of Al₂O₃and TiO₂nanoparticles on membranes in an anaerobic environment. Fatty acid profiles of cultures after exposure to Al₂O₃or TiO₂nanoparticles were analyzed and compared with the profiles of non-exposed cultures or cultures exposed to bulk materials. Analysis revealed dose–effect changes in membrane composition exclusively when cells were exposed to Al₂O₃nanoparticles in a concentration range of 3–5 g/L, but were not present in cultures exposed to bulk material. On the other hand, the tested concentrations of nano-TiO₂did not significantly affect the membrane profile of the exposed bacterium. The results suggest the possibility that Al₂O₃induces changes in bacterial membranes by direct physical interaction, which was supported by TEM image analysis.
1 Chair of Microbiology, Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Vecna pot 111, 1000 Ljubljana, Slovenia
2 Chair for Microbiology and Biotechnology, ...Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Groblje 3, 1230 Domzale, Slovenia
The membrane fatty acid composition of Escherichia coli becomes conditioned during periodic temperature cycling between 37 and 8 °C. After several cycles of temperature change, the bacteria become locked into a low-temperature physiology. Even after a prolonged incubation at high temperature the membrane fatty acid composition of conditioned cells was similar to that of cold-stressed cells.
Correspondence David Stopar david.stopar{at}bf.uni-lj.si
Abbreviations: ; C16 : 1, palmitoleic acid; C17 : 0cyc, methylene hexadecanoic acid; C18 : 1, cis -vaccenic acid; SFA, saturated fatty acid; UFA, unsaturated fatty acid
We have studied the genotoxicity of TiO sub(2) particles with a Comet assay on a unicellular organism, Tetrahymena thermophila. Exposure to bulk- or nano-TiO sub(2) of free cells, cells embedded in ...gel or nuclei embedded in gel, all resulted in a positive Comet assay result but this outcome could not be confirmed by cytotoxicity measures such as lipid peroxidation, elevated reactive oxygen species or cell membrane composition. Published reports state that in the absence of cytotoxicity, nano- and bulk-TiO sub(2) genotoxicity do not occur directly, and a possible explanation of our Comet assay results is that they are false positives resulting from post festum exposure interactions between particles and DNA. We suggest that before Comet assay is used for nanoparticle genotoxicity testing, evidence for the possibility of post festum exposure interactions should be considered. The acellular Comet test described in this report can be used for this purpose.
Ustrezno izvajanje ukrepov za obvladovanje problematike onesnaženosti prostora je v veliki meri odvisno od nepretrganega spremljanja trenutnega stanja okolja. Zakonsko predpisane preiskave v ...Sloveniji večinoma temeljijo na spremljanju fizikalnih in kemijskih kazalcev. Ker s takimi analizami ne moremo ugotoviti biološkega učinka, medsebojnega vpliva posameznih sestavin v vzorcu in bioaktivacije, je za celovitejši pregled mehanizmov in intenzivnosti vplivov okolja na organizme kemijsko fizikalne podatke potrebno dopolniti še z rezultati bioloških testov za toksičnost in genotoksičnost. V tej raziskavi smo preizkusili primernost komercialnega testnega kita za ugotavljanje toksičnosti Thamnotoxkit FTM s sladkovodnim rakcem Thamnocephalus platyurus, primernost mikrobnega testa Ames s sevi TA97, TA98 in TA100 bakterije Salmonella typhimurium in kometnega testa z evkariontskim mikroorganizmom Tetrahymena thermophila za ugotavljanje genotoksičnosti. Z izbranimi biotesti smo ovrednotili toksičnost in genotoksičnost vzorcev jezerske vode iz vzorčnih lokacij v Šaleški dolini in biološke učinke primerjali z izmerjenimi fizikalno-kemijskimi parametri.
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