title: Differences in biomass degradation between newly isolated environmental strains of Clostridium thermocellum and heterogeneity in the size of the cellulosomal scaffoldin.
abstract: Cellulolytic bacterial strains with high activity were isolated from cellulose degrading enrichment cultures derived from thermophilic biogas plants and environmental samples. The 16S rRNA gene sequences of the strains revealed >99.8% sequence identity and affiliation with the species Clostridium thermocellum. The strains differed in their ability to degrade crystalline cellulose, especially at an elevated temperature of up to 67 °C and at relatively low pH values (pH 6.5). To evaluate the influence of amino acid sequences on the discrepancies in cellulose degradation efficacy, the gene for the major cellulosomal component CelR was sequenced for all strains. The sequences were found to be almost identical (>99%). In contrast, the cellulosomal scaffoldin gene cipA showed more differences in the amino acid sequence and contained 8 or 9 cohesin modules, which indicated a different size of the cellulosome depending on the isolate. Based on MALDI-TOF MS analysis the relative abundance of important cellulosomal enzyme classes was determined. The strains with better biomass degradation properties (BC1 and NB2) had a significantly higher fraction of xylanases.
authors.affiliation: Chair of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, D-85350 Freising-Weihenstephan, Germany.
authors.forename: D E
authors.initials: DE
authors.lastname: Koeck
authors.affiliation: Chair of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, D-85350 Freising-Weihenstephan, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Koellmeier
authors.affiliation: Chair of Microbiology, Technische Universität München, 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: V V
authors.initials: VV
authors.lastname: Zverlov
authors.affiliation: Chair of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, D-85350 Freising-Weihenstephan, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Liebl
authors.affiliation: Chair of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, D-85350 Freising-Weihenstephan, Germany. Electronic address: wschwarz@wzw.tum.de.
authors.forename: W H
authors.initials: WH
authors.lastname: Schwarz
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D019149:Bioreactors / Q000382:microbiology*; D001711:Biotransformation; D002352:Carrier Proteins / Q000235:genetics*; D002482:Cellulose / Q000378:metabolism*; D044603:Cellulosomes / Q000737:chemistry / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D048013:Acetivibrio thermocellus / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D004783:Environmental Microbiology; D014644:Genetic Variation; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics; D017422:Sequence Analysis, DNA; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; C119069:CelR protein, bacteria; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D012097:Repressor Proteins; C074074:cellulose binding protein A, Clostridium cellulovorans; D002482:Cellulose
keywords: Biogas plant; Cellulosome; Clostridium thermocellum; Isolation; Scaffoldin