Cellulase and xylanase release from Bacteroides succinogenes and its importance in the rumen environment
During growth of Bacteroides succinogenes in a liquid medium with cellulose as the source of carbohydrate, greater than 80% of the carboxymethylcellulase (endo-beta-1,4-glucanase), xylanase, and aryl-beta-xylosidase and 50% of the aryl-beta-glucosidase released from cells into the culture fluid. Less than 25% of the cellobiase activity was detected in the culture fluid. Approximately 50% of each of the released enzymes measured was associated with sedimentable subcellular membrane vesicles. The vesicles appeared to be released from the outer membrane of intact cells by bleb formation, primarily in pockets between the cells and the cellulose, although a few unattached cells with blebs were seen. Many vesicles were seen adhering to cellulose, and they were also seen free in the culture fluid. These data suggest that Bacteroides succinogenes releases hydrolytic enzymes in non-sedimentable and particulate forms during growth by a mechanism which has until now received little attention. Cellulose incubated in a porous nylon bag in the rumen was colonized by bacteria resembling Bacteroides succinogenes, and subcellular vesicles were seen penetrating channels and fractures in the cellulose. On this basis, it is suggested that bacteroides succinogenes cells in the rumen contribute to an extracellular population of subcellular vesicles that possess cellulolytic and hemicellulolytic activities which probably enhance polymer digestion and provide a source of sugars for microbes lacking polymer-degrading activity, thereby contributing to a stable heterogeneous microbial population. (Refs. 46).
- Research Organization:
- Dept. Microbiology, Coll. of Biological Science, Univ. Guelph, Guelph, Ontario, Canada N1G 2W1
- OSTI ID:
- 5083108
- Journal Information:
- Appl. Environ. Microbiol.; (United States), Vol. 42:5
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BACTERIA
CELLULOLYTIC ACTIVITY
CELLULOSE
ENZYMATIC HYDROLYSIS
CELLULASE
COTTON
CULTURE MEDIA
DIGESTION
FIBERS
FORAGE
RUMINANTS
STOMACH
STRAW
SUBSTRATES
XYLANASE
ANIMAL FEEDS
ANIMALS
BODY
CARBOHYDRATES
CHEMICAL REACTIONS
DECOMPOSITION
DIGESTIVE SYSTEM
ENZYME ACTIVITY
ENZYMES
FOOD
GASTROINTESTINAL TRACT
GLYCOSYL HYDROLASES
HYDROLASES
HYDROLYSIS
LYSIS
MAMMALS
MICROORGANISMS
O-GLYCOSYL HYDROLASES
ORGANIC COMPOUNDS
ORGANS
PLANTS
POLYSACCHARIDES
SACCHARIDES
SOLVOLYSIS
VERTEBRATES
550700* - Microbiology