Submitted to: Microbial Ecology International Symposium
Publication Type: Proceedings
Publication Acceptance Date: 8/25/2006
Publication Date: 8/25/2006
Citation: Ziemer, C.J., Morrison, M. 2006. Bacteria isolated from long-term fermentations of swine feces fed xylan and pectin. In: Proceedings of Microbial Ecology International Symposium. 11th International Symposium on Microbial Ecology, August 20-25, 2006, Vienna, Austria. 2007 CDROM. Interpretive Summary:
Technical Abstract: The ability to study pure cultures of anaerobic bacteria found in gastrointestinal environments is important to understanding their role in degradation of food and production of fermentation products. Long-term in vitro fermentations were designed to selectively enrich for bacteria found in swine feces that ferment xylan-pectin (in a 2:1 ratio,X-P) as their carbohydrate source. Swine feces was collected immediately after excretion, transported to the laboratory and diluted 1 in 10 (w/v) in anaerobic phosphate buffered solution. After homogenizing for three minutes, 350 ml of slurry was added to fermentation vessels containing 350 ml of medium without added carbohydrates. Three g of X-P was added to the vessel and the contents were allowed to sit for approximately 18 h after which medium flow was started. Fermenter contents were continuously mixed and sparged with nitrogen with temperature maintained at 38 degrees C and pH at 6.8. Medium flow rate was 0.03%/h and 3 g of X-P was fed twice daily. Fermenters were maintained for 8 weeks with samples taken for bacterial isolations on weeks 4, 6, and 8. Gram stain and cell morphology were determined prior to cell preservation and DNA extraction. Based on 16S rRNA gene sequencing, most of the isolates were closely related to G+C Gram positive Clostridium and Eubacterium species, with Bacteroides species being the next most common grouping. About 30% of isolates were most closely related to sequences of uncultured bacterial clones. The isolation of these bacteria will allow us to study their role in fermentation in the swine gastrointestinal tract.