VAAM-Jahrestagung 2011 Karlsruhe, 3.–6. April 2011

and at least 99.5% of their respective complexes. Our results suggest that ifBoNT or their complexes were deliberately released into the milk supplychain, standard pasteurization conditions would reduce their activity muchmore dramatically than originally anticipated, and thus lower the threat levelof the widely discussed BoNT in milk scenario.OTP005Synthesis and characterization of the bacteriocinproduced by the Enteroccocus VL47 strain in thepresence of prebioticsE. Vamanu*USAMVB & Biotehnol Center, Industrial Biotechnology, Bucharest,RomaniaThe probiotic cultures of lactic bacteria synthesizing bacteriocins are used inthe food industry to obtain yoghurt and other dairy products. These peptideshave a special practical importance due to the thermostability, which isdemonstrated even for small concentrations, in case of peptides isolated byprecipitation. This is one of the most important properties of the probioticstrains of lactic bacteria synthesizing bacteriocins. In order to obtainprobiotic products, in addition to the capacity of synthesizing bacteriocins,the strains must adhere and colonize the intestinal tract.The aim of the study was to determine the effect of the prebiotics on thesynthesis of a bacteriocin, as well as to provide its partial biochemicalcharacterization. The Enteroccocus faecium VL47 strain producingbacteriocins was used. Bacillus cereus CMGB 215, Listeria innocua CMGB218 and Escherichia coli CBAB2 were used as sensitive strains. Thesynthesis of the bacteriocin was tested by using the MRS medium, even ifthe carbon source was replaced by other carbohydrates. In order todetermine the prebiotics effect on the synthesis of the bacteriocin, MRS wassupplemented by 1% prebiotic. The partial biochemical characterization ofthe bacteriocin was realized by determining the thermostability (at 60, 80,100 and 121 0 C, for 15 minutes), pH (2, 5, 7, 9, 11), enzymes (proteolyticand nonproteolytic) and organic solvents with a concentration of 10%. Thepartial purification of the bacteriocin was made by adding ammoniumsulphate.Due to the resistance to pH and T, the bacteriocin can be used to obtainproducts acting on the biological control of the human gut flora. The studiesindicated that the used prebiotic influenced directly the inhibiting capacity.It was proved that lactulose with a concentration of 1% determined themaximum inhibiting capacity. The bacteriocin was still active in thepresence of nonproteolytic enzymes.- Emanuel Vamanu, Adrian Vamanu, Pelinescu Diana, 2010, Synthesis and Partial BiochemicalCharacterization of the Bacteriocin produced by the Lactobacillus paracasei YR strain, Revista deChimie, 61, 5, 502-505.- Emanuel Vamanu, Adrian Vamanu, 2010, The influence of prebiotics on bacteriocin synthesis usingthe strain Lactobacillus paracasei CMGB16, African Journal of Microbiobiology Research, 4, 7, 534-537.OTP006Will not be presented!OTP007Virus elimination in the wastewater treatment plant ofHerrenhausen in HannoverK.-H. Rosenwinkel, S. Wolter, K. Ulbricht*Institute of Sanitary Engineering and Waste Management, LeibnizUniversity, Hannover, GermanyThe total virus load of wastewater can be reduced during the wastewatertreatment process in a municipal plant. In untreated wastewater an averageof 1-80.000 infectious particles per litre is detectable [1]. The currentresearch project is focussed on enhancing the efficiency of the viruselimination in activated sludge systems by adjusting the operating conditions(e.g.: sludge age, sludge loading, pH, temperature etc.) within the limits ofmaintaining the treatment performance. We were looking for an indicatororganism which behaves like pathogenic viruses in wastewater, but is safe towork with in laboratories. Therefore we decided to use bacteriophagesφX174 and MS2, infecting Escherichia coli instead of human cells. Incontrast to human pathogenic viruses bacteriophages can multiply inwastewater treatment plants (WWTPs), so it is necessary to determine theirpotential of growth to find out if they are suitable indicator organisms forour study.For this reason, we examined the virus concentration in the effluent of theprimary treatment step, in the activated sludge and the effluent of theclarifier. Measuring a concentration of 3,98*10 3 PFU ml -1 in the primarytreatment step and approximately 3,88*10 1 PFU ml -1 in the effluent of theclarifier we observed a virus reduction of about two log levels within theplant. The concentrations in the effluent of the primary treatment were equalto those in the activated sludge. During rainfall events the PFU increased byone log level at all sampling points. The comparison of the host (E. coli)CFU with the CFU of all cultivable bacteria in the activated sludgeindicated, that a multiplication of the phages should be possible, because ofthe sufficient E.coli-concentrations of ca. 1,04*10 4 CFU ml -1 . Additionallythe sensitivity of isolated E. coli strains from the activated sludge againstφX174 and MS2 was determined. We observed that ca. 84% of the testedisolates were sensitive against at least one of the bacteriophages. Still bothof these issues had no detectable effect on the overall concentration in theactivated sludge system. Consequently this indicates that the chosenbacteriophages are suitable indicator organisms to represent the growthcharacteristics of pathogenic viruses in wastewater.[1] Farrah, S.R. (2000): Abwasser. In: Walter R (Hrsg.) Umweltvirologie. Springer, Wien New York,p. 119-146.OTP008Recombinant Clostridium acetobutylicum expressingClostridium perfringens enterotoxin (CPE) for treatmentof pancreatic cancerS. König*, D. Meisohle, P. DürreInstitute of Microbiology und Biotechnology, University of Ulm, Ulm,GermanyThe prognosis for patients diagnosed with pancreatic cancer is very poor.The five-year survival rate is less than 5 % and therefore for most patientsonly a palliative treatment is possible. Genetically modified clostridia offer aconvincing potential for anti-tumor treatment. Clostridial spores onlygerminate in hypoxic regions of solid tumors. The selective tumorcolonisation enables a specific delivery of reactive agents directly to theirtargets. C. perfringens enterotoxin CPE interacts with claudin-4 receptors,which are up to 1000fold overexpressed in pancreatic carcinoma cell lines.The binding of CPE to these receptors results in the formation of pores thatfinally cause cell death. An engineered C. acetobutylicum strain was able toproduce and secrete the toxin into the surrounding medium. However, thelevel of production proved to be too low for therapy in an in vivo mousemodel. Thus, an advanced CPE expression system for C. acetobutylicum isrequired. First, we tested a number of different clostridial signal peptides,but in E. coli the produced fusion proteins led to the death of the host.Therefore, the Tet-system was chosen as a potential expression systemwhich is strictly regulated, so that in E. coli no fusion protein will beproduced.OTP009Distribution and respiratory activity of bacteria incapillary fringesD. Jost*, C. Gallert, J. WinterDepartment of Biology for Engineers, Karlsruhe Institute of Technology(KIT), Karlsruhe, GermanyThe capillary fringe (CF) is a commonly oligotrophic soil ecosystem, whichoriginates from the capillary water suction above the groundwater level. Forsoil bacteria it offers a broad range of growth conditions, which differ inparameters like water saturation or oxygen concentration. In this study,experiments in thin glass chambers (Hele-Shaw cells, 20 x 20 x 0.2 cm),filled with silica sand or glass beads were conducted. The CF was generatedby hanging the Hele-Shaw cell into a tray with bacterial suspension, so thatthe bacteria were transported into the CF via capillary forces. Three types ofbacteria were used: Pseudomonas putida (motile), Corynebacteriumglutamicum (non-motile), Escherichia coli (motile, gfp labeled for bettervisualization).The tests revealed that the saturated/unsaturated interface region at 60 - 85% water saturation offers best growth conditions for all bacteria types.Immobile bacteria and bacteria with a hydrophobic surface were not able toreach the upper end of the CF [1]. Cells were mostly suspended in theaqueous phase and only in the interface region attachment of cells to thespektrum | Tagungsband 2011