Cluster structure of anaerobic aggregates of an expanded granular sludge bed reactor
| Autor: | A.C. van Aelst, A. I. Versprille, G. Gonzalez-Gil, H. van As, Gatze Lettinga, Piet N.L. Lens |
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| Jazyk: | angličtina |
| Rok vydání: | 2001 |
| Předmět: |
Laboratorium voor Plantencelbiologie
Deltaproteobacteria Magnetic Resonance Spectroscopy Chemical structure Biophysics Mineralogy Acetates Euryarchaeota Waste Disposal Fluid Applied Microbiology and Biotechnology Bacterial Adhesion Methanosaeta law.invention Bacteria Anaerobic Bioreactors law Life Science Organic matter Biomass In Situ Hybridization Fluorescence chemistry.chemical_classification WIMEK Sewage Ecology biology Physiology and Biotechnology biology.organism_classification Laboratory of Plant Cell Biology Biofysica Chemical engineering chemistry Volatile suspended solids Microscopy Electron Scanning Ultrastructure Environmental Technology Milieutechnologie Electron microscope Methane Food Science Biotechnology Mesophile Waste disposal |
| Zdroj: | Applied and Environmental Microbiology 67 (2001) 8 Applied and Environmental Microbiology, 67(8), 3683-3692 |
| ISSN: | 0099-2240 |
| Popis: | The metabolic properties and ultrastructure of mesophilic aggregates from a full-scale expanded granular sludge bed reactor treating brewery wastewater are described. The aggregates had a very high methanogenic activity on acetate (17.19 mmol of CH 4 /g of volatile suspended solids [VSS]·day or 1.1 g of CH 4 chemical oxygen demand/g of VSS·day). Fluorescent in situ hybridization using 16S rRNA probes of crushed granules showed that 70 and 30% of the cells belonged to the archaebacterial and eubacterial domains, respectively. The spherical aggregates were black but contained numerous whitish spots on their surfaces. Cross-sectioning these aggregates revealed that the white spots appeared to be white clusters embedded in a black matrix. The white clusters were found to develop simultaneously with the increase in diameter. Energy-dispersed X-ray analysis and back-scattered electron microscopy showed that the whitish clusters contained mainly organic matter and no inorganic calcium precipitates. The white clusters had a higher density than the black matrix, as evidenced by the denser cell arrangement observed by high-magnification electron microscopy and the significantly higher effective diffusion coefficient determined by nuclear magnetic resonance imaging. High-magnification electron microscopy indicated a segregation of acetate-utilizing methanogens ( Methanosaeta spp.) in the white clusters from syntrophic species and hydrogenotrophic methanogens ( Methanobacterium -like and Methanospirillum -like organisms) in the black matrix. A number of physical and microbial ecology reasons for the observed structure are proposed, including the advantage of segregation for high-rate degradation of syntrophic substrates. |
| Databáze: | OpenAIRE |
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