Lenz, Markus
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Lenz, Markus
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- PublikationCharacterization of heavy metal toxicity in some plants and microorganisms—A preliminary approach for environmental bioremediation(Elsevier, 13.01.2020) Diaconu, Mariana; Corvini, Philippe; Lenz, Markus [in: New Biotechnology]01A - Beitrag in wissenschaftlicher Zeitschrift
- PublikationBiodegradation of sulfamethoxazole by a bacterial consortium of Achromobacter denitrificans PR1 and Leucobacter sp. GP(Springer, 12/2018) Reis, Ana C.; Cvancarova Småstuen, M.; Liu, Ying; Lenz, Markus; Hettich, Timm; Kolvenbach, Boris; Corvini, Philippe; Nunes, Olga C. [in: Applied Microbiology and Biotechnology]In the last decade, biological degradation and mineralization of antibiotics have been increasingly reported feats of environmental bacteria. The most extensively described example is that of sulfonamides that can be degraded by several members of Actinobacteria and Proteobacteria. Previously, we reported sulfamethoxazole (SMX) degradation and partial mineralization by Achromobacter denitrificans strain PR1, isolated from activated sludge. However, further studies revealed an apparent instability of this metabolic trait in this strain. Here, we investigated this instability and describe the finding of a low-abundance and slow-growing actinobacterium, thriving only in co-culture with strain PR1. This organism, named GP, shared highest 16S rRNA gene sequence similarity (94.6–96.9%) with the type strains of validly described species of the genus Leucobacter. This microbial consortium was found to harbor a homolog to the sulfonamide monooxygenase gene (sadA) also found in other sulfonamide-degrading bacteria. This gene is overexpressed in the presence of the antibiotic, and evidence suggests that it codes for a group D flavin monooxygenase responsible for the ipso-hydroxylation of SMX. Additional side reactions were also detected comprising an NIH shift and a Baeyer–Villiger rearrangement, which indicate an inefficient biological transformation of these antibiotics in the environment. This work contributes to further our knowledge in the degradation of this ubiquitous micropollutant by environmental bacteria.01A - Beitrag in wissenschaftlicher Zeitschrift
- PublikationRhizobacteria and Plant Symbiosis in Heavy Metal Uptake and Its Implications for Soil Bioremediation(Elsevier, 2017) Sobariu, Dana Luminita; Fertu, Daniela Ionela; Diaconu, Mariana; Pavel, Lucian Vasile; Hlihor, Raluca-Maria; Dragoi, Elena Niculina; Curteanu, Silvia; Lenz, Markus; Corvini, Philippe; Gavrilescu, Maria [in: New Biotechnology]Certain species of plants can benefit from synergistic effects with plant growth-promoting rhizobacteria (PGPR) that improve plant growth and metal accumulation, mitigating toxic effects on plants and increasing their tolerance to heavy metals. The application of PGPR as biofertilizers and atmospheric nitrogen fixators contributes considerably to the intensification of the phytoremediation process. In this paper, we have built a system consisting of rhizospheric Azotobacter microbial populations and Lepidium sativum plants, growing in solutions containing heavy metals in various concentrations. We examined the ability of the organisms to grow in symbiosis so as to stimulate the plant growth and enhance its tolerance to Cr(VI) and Cd(II), to ultimately provide a reliable phytoremediation system. The study was developed at the laboratory level and, at this stage, does not assess the inherent interactions under real conditions occurring in contaminated fields with autochthonous microflora and under different pedoclimatic conditions and environmental stresses. Azotobacter sp. bacteria could indeed stimulate the average germination efficiency of Lepidium sativum by almost 7%, average root length by 22%, average stem length by 34% and dry biomass by 53%. The growth of L. sativum has been affected to a greater extent in Cd(II) solutions due its higher toxicity compared to that of Cr(VI). The reduced tolerance index (TI, %) indicated that plant growth in symbiosis with PGPR was however affected by heavy metal toxicity, while the tolerance of the plant to heavy metals was enhanced in the bacteria-plant system. A methodology based on artificial neural networks (ANNs) and differential evolution (DE), specifically a neuro-evolutionary approach, was applied to model germination rates, dry biomass and root/stem length and proving the robustness of the experimental data. The errors associated with all four variables are small and the correlation coefficients higher than 0.98, which indicate that the selected models can efficiently predict the experimental data.01A - Beitrag in wissenschaftlicher Zeitschrift
- PublikationEnvironmental aspects of printable and organic electronics (POE)(04/2016) Hengevoss, Dirk; Zimmermann, Yannick; Brun, Nadja; Hugi, Christoph; Corvini, Philippe; Lenz, Markus; Fent, Karl; Nisato, Giovanni; Lupo, Donald; Ganz, Simone [in: Organic and Printed Electronics: Fundamentals and Applications]04 - Beitrag Sammelband oder Konferenzschrift
- PublikationImmobilization of an artificial imine reductase within silica nanoparticles improves its performance(Royal Society of Chemistry, 2016) Hestericová, Martina; Correro, Maria Rita; Lenz, Markus; Corvini, Philippe; Shahgaldian, Patrick; Ward, Thomas R. [in: Chemical Communications]Silica nanoparticles equipped with an artificial imine reductase (biotinylated iridium complex conjugated with streptavidin) display marked redn. activity toward cyclic imines and NAD. The method, based on immobilization and protection of streptavidin on silica nanoparticles, shields the biotinylated metal cofactor against deactivation yielding >46,000 turnovers in pure samples and 4000 turnovers in crude cellular exts.01A - Beitrag in wissenschaftlicher Zeitschrift
- PublikationArsenic Mobilization from Historically Contaminated Mining Soils in a Continuously Operated Bioreactor: Implications for Risk Assessment(Taylor & Francis, 2016) Rajpert, Liwia; Kolvenbach, Boris; Ammann, Erik; Hockmann, Kerstin; Nachtegaal, Maarten; Eiche, Elisabeth; Schäffer, Andreas; Corvini, Philippe; Sklodowska, Aleksandra; Lenz, Markus [in: Environmental Science & Technology]Concentrations of soil arsenic (As) in the vicinity of the former Złoty Stok gold mine (Lower Silesia, southwest Poland) exceed 1000 μg g–1 in the area, posing an inherent threat to neighboring bodies of water. This study investigated continuous As mobilization under reducing conditions for more than 3 months. In particular, the capacity of autochthonic microflora that live on natural organic matter as the sole carbon/electron source for mobilizing As was assessed. A biphasic mobilization of As was observed. In the first two months, As mobilization was mainly conferred by Mn dissolution despite the prevalence of Fe (0.1 wt % vs 5.4 for Mn and Fe, respectively) as indicated by multiple regression analysis. Thereafter, the sudden increase in aqueous As[III] (up to 2400 μg L–1) was attributed to an almost quintupling of the autochthonic dissimilatory As-reducing community (quantitative polymerase chain reaction). The aqueous speciation influenced by microbial activity led to a reduction of solid phase As species (X-ray absorption fine structure spectroscopy) and a change in the elemental composition of As hotspots (micro X-ray fluorescence mapping). The depletion of most natural dissolved organic matter and the fact that an extensive mobilization of As[III] occurred after two months raises concerns about the long-term stability of historically As-contaminated sites.01A - Beitrag in wissenschaftlicher Zeitschrift
- PublikationBiomineralisierung von Selen: Von Abwasserbehandlung zu Ressourcen-Wiedergewinnung(2015) Lenz, Markus; Kolvenbach, Boris; Corvini, Philippe06 - Präsentation
- PublikationAre degrading OPV materials still sustainable?(2015) Zimmermann, Yannick; Brun, Nadja; Hengevoss, Dirk; Corvini, Philippe; Fent, Karl; Hugi, Christoph; Lenz, Markus06 - Präsentation