Ruminococcus albus

Synergism between a-arabinosidase, xylanase and j8-xylosidase has been demonstrated in the hydrolysis of wheat straw arabinoxylan with purified enzymes of T, reesei (71). > en only xylanase and )8-xylosidase were used in the hydrolysis, the xylose yield was only 66% of that produced by the whole culture filtrate at the same activity levels of these two enzymes, and no arabinose was produced. Addition of a-arabinosidase increased the yields of both xylose and arabinose. Enhanced hydrolytic action of hemicellulolytic or pectinolytic enzymes in the hydrolysis of alfalfa cell wall polymers by addition of Ruminococcus albus a-arabinosidase has also been reported (37). 

Leatherwood (49) interprets his observations made with roll tube cultures of the anaerobic bacterium Ruminococcus albus to indicate that a single cellulase complex is formed from enzymes diffusing from two different colony types. He discussed the mechanism in terms of a non-... 

Physical or chemical modification of a substrate may additionally selectively affect transformation or uptake Keil and Kirchman (1992) compared the degradation of Rubisco uniformly labeled with 3H amino acids produced via in vitro translation to Rubisco that was reductively methylated with 3H-methane. Although both Rubisco preparations were hydrolyzed to lower molecular weights at approximately the same rate, little of the methylated protein was assimilated or respired. The presence of one substrate may also inhibit uptake of another, as has been demonstrated for anaerobic rumen bacteria. Transport and metabolism of the monosaccharides xylose and arabinose were strongly reduced in Ruminococcus albus in the presence of cellobiose (a disaccharide of glucose), likely because of repression of pentose utilization in the presence of the disaccharide. Glucose, in contrast, competitively inhibited xylose transport and showed noncompetitive inhibition of arabinose transport, likely because of inactivation of arabinose permease (Thurston et al., 1994). 

Thurston, B., K. A. Dawson, and H. J. Strobel. 1993. Cellobiose versus glucose utilization by the ruminal bacterium Ruminococcus albus. Applied Environmental Microbiology 59 2631-2637. 

Ruminococcus albus strain 7, (1), was grown on cellulose roll tubes according to the Hungate technique (2). Either Avicel (FMC Corporation, Marcus Hook, Pa.) or balled filter paper was used as the cellulose source. Three milliliters of melted cellulose-medium at 45 °C. in 16 X 150 mm. tubes were inoculated with the bacteria under a gas phase of 95% C02 and 5% H2. The tubes were subsequently stoppered and rolled in a tray of ice in order to form a film of agar medium around the... 

Several observations related to this phenomenon have been made on the cellulase of Ruminococcus albus strain 7. Crystalline cellulose is degraded by this organism. Cell-free preparations are active in decreasing the turbidity of cellulose suspensions. The amount of hydrolytic activity against soluble cellulose derivatives is not different for the three variants. Two major cellulolytic components have been separated by... 

Guar gum, locust bean gum (galactomannan) Bacteroides ovatus Bacteroides uniformis Ruminococcus albus... 

Cellvibro gilvus Clostridium thermocellum Bacteroides succinogenus Ruminococcus albus Psudonomas fluorescence var cellulosa Sporocytophaga myxococcides... 

Yanase H, Yamamoto K, Sato D, Okamoto K. (2005b). Ethanol production from cellohiose hy Zymobacterpalmae carrying the Ruminococcus albus (3-glucosidase gene. J Biotechnol, 118, 35-43. 

Bacteria of the species Clostridium thermocellum degrade crystalline cellulose efficiently (Fig. 6). They occur most frequently in metagenome analysis data (Wirth et al. 2012 Krause et al. 2008). Other cellulolytic bacteria with high sequence abundance (within the 40 most frequently found species) were Clostridium cellulolyticum, Ruminococcus albus, Clostridium saccharolyticum, and Caldicellu-losiruptor saccharolyticus (Wirth et al. 2012). The high abundance of cellulolytic members in the Clostridia indicates the important role of these bacteria for degradation of complex substrates in the natural remineralization of biomass. 

Cellulase complexes similar to the cellulosomes of C. thermocellum were also identified in other cellulolytic bacteria such as the mesophilic species C. cellulovorans, C. cellulolyticum, C. papyrosolvens, Bacteroides cellulosolvens, Acetivibrio cellulolyticus,Ruminococcus albus, and Ruminococcus flavefaciens and the thermophilic species Clostridium clariflavum and Clostridium josui. They... 

Ntaikou, I., Gavala, H.N., Komaros, M., Lyberatos, G., 2008. Hydrogen production from sugars and sweet sorghum biomass using Ruminococcus albus. International Journal of Hydrogen Energy 33, 1153-1163. 

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