title: Comparative genotyping of Clostridium thermocellum strains isolated from biogas plants: genetic markers and characterization of cellulolytic potential.
abstract: Clostridium thermocellum is among the most prevalent of known anaerobic cellulolytic bacteria. In this study, genetic and phenotypic variations among C. thermocellum strains isolated from different biogas plants were determined and different genotyping methods were evaluated on these isolates. At least two C. thermocellum strains were isolated independently from each of nine different biogas plants via enrichment on cellulose. Various DNA-based genotyping methods such as ribotyping, RAPD (Random Amplified Polymorphic DNA) and VNTR (Variable Number of Tandem Repeats) were applied to these isolates. One novel approach - the amplification of unknown target sequences between copies of a previously discovered Random Inserted Mobile Element (RIME) - was also tested. The genotyping method with the highest discriminatory power was found to be the amplification of the sequences between the insertion elements, where isolates from each biogas plant yielded a different band pattern. Cellulolytic potentials, optimal growth conditions and substrate spectra of all isolates were characterized to help identify phenotypic variations. Irrespective of the genotyping method used, the isolates from each individual biogas plant always exhibited identical patterns. This is suggestive of a single C. thermocellum strain exhibiting dominance in each biogas plant. The genotypic groups reflect the results of the physiological characterization of the isolates like substrate diversity and cellulase activity. Conversely, strains isolated across a range of biogas plants differed in their genotyping results and physiological properties. Both strains isolated from one biogas plant had the best specific cellulose-degrading properties and might therefore achieve superior substrate utilization yields in biogas fermenters.
authors.affiliation: Department of Microbiology, TechnischeUniversitätMünchen, Emil-Ramann-Str. 4, D-85350 Freising-Weihenstephan, Germany.
authors.forename: Daniela E
authors.initials: DE
authors.lastname: Koeck
authors.affiliation: Department of Microbiology, TechnischeUniversitätMünchen, Emil-Ramann-Str. 4, D-85350 Freising-Weihenstephan, Germany; Institute of Molecular Genetics, Russian Academy of Science, Kurchatov Sq. 2, 123182 Moscow, Russia.
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Zverlov
authors.affiliation: Department of Microbiology, TechnischeUniversitätMünchen, Emil-Ramann-Str. 4, D-85350 Freising-Weihenstephan, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Liebl
authors.affiliation: Department of Microbiology, TechnischeUniversitätMünchen, Emil-Ramann-Str. 4, D-85350 Freising-Weihenstephan, Germany. Electronic address: wschwarz@wzw.tum.de.
authors.forename: Wolfgang H
authors.initials: WH
authors.lastname: Schwarz
mesh_terms: D001483:Base Sequence; D056804:Biofuels / Q000382:microbiology*; D002482:Cellulose / Q000378:metabolism*; D048013:Acetivibrio thermocellus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005819:Genetic Markers; D014644:Genetic Variation; D005838:Genotype; D007218:Industrial Microbiology; D008969:Molecular Sequence Data; D058889:Molecular Typing; D010641:Phenotype; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D056804:Biofuels; D004269:DNA, Bacterial; D005819:Genetic Markers; D002482:Cellulose
keywords: Biogas; Cellulolytic potential; Clostridium thermocellum; Genotyping; Isolation