TY - GEN A1 - Rathsack, Kristina A1 - Böllmann, Jörg A1 - Martienssen, Marion T1 - Comparative Study of Different Methods for Analyzing Denitrifying Bacteria in Fresh Water Ecosystems T2 - Journal of Water Resource and Protection N2 - Bacteria capable of denitrification play a significant role in the nitrogen cycle of freshwater ecosystems. By metabolizing nitrogen compounds they e.g. counteract the eutrophication of natural waters. To get detailed insights into the in situ turnover rates of nitrogen a reliable tool of quantification for active microorganisms is essential. In the present investigation, quantification capabilities of a molecular tool (Polymerase Chain Reaction—PCR) and a cultivation based tool (Most probable number—MPN) were investigated and compared. The total bacterial concentration yielded by the molecular PCR approach was up to 6-fold higher compared to the results of the MPN approach. However, the portion of culturable denitrifying bacteria compared to the number of specific gene copies (nirS) was much lower. Depending on the environmental conditions, the difference between the PCR and the MPN approach was up to three orders of magnitude. From lab scale experiments with a pure P. aeroginosa strain it can be concludes, that these differences are not the result of inappropriate culture conditions but rather reflect the portion of so called viable but not culturable bacteria (VBNC). Low nitrate concentrations as found in many fresh water ecosystems induced a significant increase in the portion of non culturable denitrifying bacteria. Referred to the investigation of dynamic populations, the number of metabolic active bacteria is represented by the MPN rather than by the PCR approach. Y1 - 2014 SN - 1945-3094 SN - 1945-3108 VL - 6 IS - 6 SP - 609 EP - 617 ER - TY - GEN A1 - Martienssen, Marion A1 - Reichel, O. A1 - Kohlweyer, U. T1 - Surface properties of bacteria from different waste water treatment plants T2 - Acta Biotechnologica Y1 - 2001 VL - 21 IS - 3 SP - 207 EP - 225 ER - TY - GEN A1 - Schmidt, Christian A1 - Kalbus, Edda A1 - Krieg, Ronald A1 - Bayer-Raich, Marti A1 - Leschik, Sebastian A1 - Reinstorf, Frido A1 - Martienssen, Marion A1 - Schirmer, Mario T1 - Contaminant mass flow rates between groundwater, strembed sediments and surface water at the regionally contaminated site Bitterfeld T2 - Grundwasser Y1 - 2008 SN - 1430-483X VL - 13 IS - 3 SP - 133 EP - 146 ER - TY - GEN A1 - Schmidt, C. A1 - Kalbus, Edda A1 - Martienssen, Marion A1 - Schirmer, Mario T1 - The influence of heterogeneous groundwater discharge on the timescales of contaminant mass flux from streambed sediments field evidence and long-term predictions T2 - Hydrology and Earth System Sciences Discussions Y1 - 2008 SN - 1812-2116 VL - 5 IS - 2 SP - 971 EP - 1001 ER - TY - GEN A1 - Muhondwa, Jacob Paul A1 - Martienssen, Marion A1 - Burkhardt, Marko T1 - Effect of high biowaste moisturie content on phatogens hygienization potential of in-vessel composting technology during compost production T2 - International Journal of Current Research Y1 - 2015 SN - 0975-833X VL - 7 IS - 4 SP - 15042 EP - 15048 ER - TY - GEN A1 - Coban, Oksana A1 - Kuschk, Peter A1 - Kappelmeyer, Uwe A1 - Spott, Oliver A1 - Martienssen, Marion A1 - Jetten, Mike S. M. A1 - Knöller, Kay T1 - Nitrogen transforming community in a horizontal subsurface-flow constructed wetland T2 - Water research Y1 - 2015 U6 - https://doi.org/0.1016/j.watres.2015.02.018 SN - 1879-2448 IS - 74 SP - 203 EP - 212 ER - TY - GEN A1 - Muhondwa, Jacob Paul A1 - Martienssen, Marion A1 - Burkhardt, Marko T1 - Feasibility of Anaerobic Digestion of Potato peels for Biogas as Mitigation of Greenhouse gases Emission Potential T2 - International journal of environmental research Y1 - 2015 SN - 1735-6865 VL - 9 IS - 2 SP - 481 EP - 488 ER - TY - GEN A1 - Böllmann, Jörg A1 - Rathsack, Kristina A1 - Martienssen, Marion T1 - The precision of bacterial quantification techniques on different kinds of environmental samples and the effect of ultrasonic treatment T2 - Journal of Microbiological Methods N2 - The precision of cell number quantification in environmental samples depends on the complexity of the sample and on the applied technique. We compared fluorescence microscopy after filtration, quantification of gene copies and the cultivation based most probable number technique for their precision. We further analyzed the effect of increasing complexity of the sample material on the precision of the different methods by using pure cultures of Pseudomonas aeruginosa, fresh water samples and sediment slurries with and without ultrasonic treatment for analyses. Microscopy reached the highest precision, which was similar between pure cultures and water samples, but lower for sediment samples due to a higher percentage of cells in clusters and flocks. The PCR based quantification was most precise for pure cultures. Water and sediment samples were similar but less precise, which might be caused by the applied DNA extraction techniques. MPN measurements were equally precise for pure cultures and water samples. For sediment slurries the precision was slightly lower. The applied ultrasonic treatment of the slurries dispersed the cell clusters and flocks, increased the precision of microscopical and MPN measurements and also increased the number of potential colony forming units. However, the culturable cell number decreased by half. For MPN quantification of viable cells in samples with a high proportion of clustered cells we therefore recommend an optimization of ultrasonic treatment and a confirmation by microscopy and cultivation to reach highest possible dispersion of the cells with a minimum of inactivation. As a result of these observations we suggest a correction factor for MPN measurements to consider the effect of sonication on complex samples. The results are most likely applicable to other complex samples such as soil or biofilms. Y1 - 2016 U6 - https://doi.org/10.1016/j.mimet.2016.05.006 SN - 0167-7012 VL - 126 SP - 42 EP - 47 ER - TY - GEN A1 - Bryant, Isaac Mbir A1 - Martienssen, Marion A1 - Burkhardt, Marko T1 - Millennium development goal on sustainable sanitation in Ghana: A reality or a mirage? T2 - African Journal of science and research Y1 - 2016 SN - 2306-5877 VL - 5 IS - 3 SP - 01 EP - 06 ER - TY - GEN A1 - Engelbrecht, Steffen A1 - Fondengcap, Mbengamina Terence A1 - Martienssen, Marion A1 - Rathsack, Kristina T1 - Highly efficient long-term storage of carrier-bound anammox biomass T2 - Water Science & Technology N2 - The anammox process is a potential alternative to the conventional nitrogen removal from wastewater. However, due to large generation times of anammox bacteria, the start-up of treatment reactors may be impeded. An efficient storage technique can handle this drawback and may be also suitable for seasonally operated treatment plants like in touristic areas. In the current study, several storage techniques were investigated with respect to its suitability for the preservation of the specific anammox activity after long-term storage. Storing conditions differed in terms of temperature, redox buffer and nutrient supplementation. The specific activity of immobilized anammox bacteria (Candidatus Kuenenia stuttgartiensis) was determined three times during a long-term preservation of 78 days and 106 days, respectively. The highest activity was ensured at a storing temperature of 4 WC, providing nitrate as redox buffer and a nutrient supplement every 23 days. Thus, 91.4% of the initial anammox activity could be preserved after a storage of 106 days. Superiority of the presented treatment condition was confirmed by a calculated nitrate-ammonium consumption rate close to the optimal ratio of 1.32. This technique provided an economical and simple method suitable for long-term storage of immobilized anammox biomass. KW - anammox KW - biofilm KW - Candidatus Kuenenia stuttgartiensis KW - long-term storage KW - reactivation Y1 - 2016 U6 - https://doi.org/10.2166/wst.2016.364 SN - 0273-1223 SN - 1996-9732 VL - 74 IS - 8 SP - 1911 EP - 1918 ER -