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Title: CLOSTRIDIUM HERBIVORANS SP. NOV., A CELLULOLYTIC ANAEROBE FROM THE PIG INTESTINE

Author
item VAREL V H - 5438-01-07
item TANNER R S - UNIVERSITY OF OKLAHOMA
item WOESE C R - UNIVERSITY OF ILLINOIS

Submitted to: International Journal of Systematic and Evolutionary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/14/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: An understanding of the bacterial species which degrade fiber in the intestinal tract of pigs is limited. Six percent of the total population of bacteria in the pig intestine degrade fiber (cellulose). This is approximately the same proportion found in the rumen. Four major bacterial species degrade cellulose in the rumen while only two have been isolated from the pig. Recently we isolated a cellulose degrading bacterial species from the pig intestine which appeared to be different from any previously described. Bacterial finger-printing (16S rRNA sequence analysis) has been completed on this species. It indicates that the bacterium is distinct from 14 other cellulose degrading bacteria that are classified within this genus. Its closest relative is a cellulose degrading bacterium found in the rumen. The new bacterium is found in high numbers as part of the normal flora within the intestine of U.S. and imported Chinese pigs, and has the ability to degrade plant forages equally or better than the ruminal cellulose degrading bacteria. The new bacterium presumably plays a major role in fiber degradation within the pig gut.

Technical Abstract: A new cellulolytic anaerobic clostridium was isolated from the intestinal tract of pigs. The isolate was a gram-positive, motile rod, formed terminal to subterminal swollen sporangia and required a fermentable carbohydrate for growth. Cellulose, cellobiose, maltose, starch and glycogen supported growth, but not glucose or fructose. The major end-products from the fermentation of cellobiose were butyrate and formate, with minor amounts of hydrogen and ethanol. Ruminal fluid (15%) or yeast extract (1%) was required for good growth. The optimum temperature for growth was 39-42 degrees C and the optimum pH was 6.8-7.2. Cell lysis occurred rapidly once stationary growth was reached. 16S rRNA sequence analysis showed that the strain was related to a group of gram-positive anaerobes including Clostridium oroticum and the cellulolytic species C. polysaccharolyticum and C. populeti. The DNA base composition of the isolate is 38 mol% G+C. We propose the name Clostridium herbivorans for the monotype strain 54408 (=ATCC 49925) of this isolate.