VAAM-Jahrestagung 2012 18.–21. März in Tübingen

219showed reduced N 2O emissions in the biochar treatments up to 84%. Ingeneral N 2O emissions were 30 times higher under anoxic conditionscompared to the emissions from the oxic microcosms. Decreased N 2Oemissions were correlated to an increase in the relative abundance of nitrousoxide reductase (nosZ) gene copy numbers during the first two weeks afterbiochar addition. Our results further showed that reduced N 2O emissions frombiochar amended soils were directly linked to changes in the functionalcomposition, nitrogen compound utilization, and activity of the nitrogentransformingmicrobial community. Overall, soil biochar amendment promotedcomplete denitrification via stimulation of growth and activity of nosZcontaining,nitrous oxide reducing denitrifiers. Our findings will facilitate thedevelopment of new mitigation strategies for anthropogenic GHGs.SMP023Microbial and metabolic analysis and optimization of CH 4production from wheat stillage at elevated temperaturesI. Röske* 1 , W. Sabra 2 , A. Sorger 1 , K. Sahm 1 , R. Daniel 3 , A.-P. Zeng 2 ,G. Antranikian 11 Hamburg University of Technology, Institute of Technical Microbiology,Hamburg, Germany2 Hamburg University of Technology, Institute for Bioprocess and BiosystemsEngeneering, Hamburg, Germany3 Georg-August-University, Department of Genomic and Applied Microbiology,Göttingen, GermanyDevelopment of an efficient bioethanol production plant based on biomassrequires the integration of various biological and non-biological processes.After the bioconversion of wheat to ethanol and the distillation processhigh amounts of lignocellulose and dead yeast cells still remain untreated(stillage). From a high-temperature biogas plant, using corn and chickenmanure as biogas substrates, a microbial community was enriched able toconvert wheat stillage to methane at 55°C.In order to investigate the microbial community in the model biogasreactor pyrosequence analysis of 16S rRNA gene-tags was conductedresulting in 23,000 gene sequences. The studies indicate the predominanceof Archaea of the genera Methanosaeta and Methanothermobacter andBacteria of the families Thermotogaceae, Anaerolineaceae,Synergistaceae and Thermodesulfobiaceae.The archaeon Methanothermobacter thermautotrophicus and the bacteriaLutispora thermophila, Thermoanaerobacter thermosaccharolyticum,Clostridium succinogenes and Thermohydrogenium kirishiense wereisolated by anaerobic serial dilution techniquesTo improve biogas production we investigated different strains for theirbioaugmentation potential. We could demonstrate that the addition of apure culture of Caldicellulosiruptor saccharolyticus to the existing biogascommunity resulted in a considerable biogas intensification rate with aconstant CO 2/CH 4 ratio.To investigate dynamics and stability of the microbial community duringprocess modifications such as increase in loading rate and addition ofaccumulating intermediates, denaturing gradient gel electrophoresis andfluorescence in-situ hybridization was employed. The results revealed thepresence of a robust consortium of methanogenic Archaea.The set of primers developed in this study provides a tool for monitoringmethanogenic communities from a wide range of biogas processes.SMP024Methanogenic communities and their response to Holoceneand Late Pleistocene climate changes in permafrostenvironmentsD. Wagner* 1 , J. Griess 1 , K. Mangelsdorf 21 Alfred Wegener Institute for Polar and Marine Research, Research UnitPotsdam, Potsdam, Germany2 Helmholtz Zentrum Potsdam Deutsches Geoforschungszentrum, Section 4.3,Potsdam, GermanyThe currently observed climate change due to global warming is expectedto have a strong impact, notably on Arctic permafrost environments. Thethawing of permafrost is suggested to be associated with a massive releaseof greenhouse gases, in particular methane. Thus, Arctic permafrostregions play a fundamental role within the global carbon cycle and thefuture development of Earth’s climate. To understand how the system willrespond to climate changes it is not only important to investigate thecurrent status of carbon turnover but also how the system reacted toclimate changes in the past.This presentation therefore takes a journey through time from the recentactive layer of permafrost to Holocene and Late Pleistocene permafrostdeposits in the Siberian Arctic, to reconstruct the microbial driven methanedynamics. Generally, in-situ methane contents of the deposits reflect theTOC profile with depth underlining the correlation of the distribution oforganic matter and methanogenesis. Significant amounts of methane couldalso be found in Late Pleistocene deposits of an age of 30 and 41 ka,respectively. Lipid biomarkers and amplifiable DNA were successfullyrecovered throughout the whole permafrost sequences with an age of up to42 ka. Analysis of the abundance and distribution of archaeol, an indicatorfor fossil methanogenic communities, revealed a temperature response toclimate changes during the Late Pleistocene and Holocene. Past warmingtrends seem to cause an enhancing of methanogenic communities, whilecooling trends conversely caused them to decrease. Furthermore,indications for recently living archaeal communities in frozen groundcould be found, using phospholipid ether lipids (PLEL) and 16S rRNAfingerprints as specific markers. The obtained data on present and pastmethanogenic communities suggest a response to future warming events aswas reconstructed from previous warmer periods.SMP025FISH in soil: applications for the in situ investigation ofmicroorganismsH. Schmidt*, T. EickhorstUniversity of Bremen, Soil Science, Bremen, GermanyFluorescence in situ hybridization (FISH) represents a powerful methodfor the phylogenetic identification, enumeration, and visualization ofsingle microbial cells in soil. The applicability of this tool for studies insoil microbiology is exemplarily shown on the basis of several FISHapproaches which are used in our lab.For routine applications of FISH in soil, the amplification of fluorescentsignals (CARD) is necessary for a clear discrimination of target signalsfrom the intense background induced by organic matter, high contents ofclay, and plant tissue. CARD-FISH in soil provides quantitative data ofsingle microbial cells, and thus gives insight into the composition ofmicrobial consortia associated with different microenvironments (e.g. bulksoil and rhizosphere).With CARD-FISH applied to roots, the enumeration of single cells as wellas the analysis of the spatial distribution of these microbes on therhizoplane gives additional information for comprehensive studies in thesoil-root interface. Especially on roots, sequential hybridizations withfluorochromes of different spectral characteristics have shown to be usefulfor the analysis of microorganisms on domain specific or hierarchic levels.The combination of FISH and micropedology (resin embedding and thinsectioning of soil samples) allows for the in situ detection of singlemicroorganisms in the undisturbed soil matrix. The simultaneous use ofmultiple oligonucleotide probes thereby provides information on thespatial distribution of microorganisms belonging to different taxonomicdivisions.In the recently developed gold-FISH protocol, conjugates labelled withfluorochromes and nanogold particles allow the combinative approach ofanalyzing microorganisms by epifluorescence and scanning electronmicroscopy. It is therefore possible to identify and localize single microbialcells in situ on an ultrastructural level. Furthermore, the biochemical conditionsin the microbial habitat of gold-FISH detected cells can be characterized byelement mapping generated with energy dispersive X-ray spectroscopy.SMP026Bacterial communities change along a glacier forefieldtransect - A combined approach of molecular fingerprints (T-RFLP) and environmental analysesF. Bajerski*, D. WagnerAlfred Wegener institute for polar and marine research, PeriglacialResearch, Potsdam, GermanyGlacier forefields are known to be a pioneer site for primary successionand inhabit extreme climatic and environmental conditions. Retreatingglaciers expose new terrestrial terrain that becomes accessible for soilformation and microbial colonisation. Pioneer microorganisms supportweathering processes and the colonisation of more complex microbialcommunities or plants. Because increasing temperatures due to climatechange enhance glacial degradation, it is important to understand howbacterial communities react to changing environmental conditions. Acombined approach of geochemical and microbiological examinations willbe used to describe the habitat characteristics and the complex system ofmicrobial communities in two glacier forefields on Larsemann Hills, EastAntarctica. Terminal Restriction Length Polymorphism Analyses showthat bacterial community structures vary significantly between glacierforefields of different development status. Although relatively low,enzyme activities increase with an advanced forefield development anddecrease with increasing depth. The extreme habitat conditions becomeapparent within the geochemical and geochemical properties. The studysite is characterised by very low nutrient and water availability and acoarse grain size. Statistics reveal a connection between environmental andbiological data and the position of the sample in the glacier forefield.Altogether our results show a high abundance and variability ofmicroorganisms in the hardly developed habitat glacier forefield.BIOspektrum | Tagungsband 2012