Ionized XXXX requirement of rumen cellulolytic bacteria.

@entity8379 @entity39989 @entity13330 @entity460 @entity141 @entity26977 @entity8294 @entity15898
Ionized @entity460 ( @entity141 ) appears to be required by the 3 predominant species of rumen cellulolytic bacteria, @entity15898 , @entity39989 , and @entity8294 . The present study evaluated the role of ionized @entity460 in growth and cellulose digestion. Maximum growth or rate and extent of digestion and lag time were the criteria used to evaluate @entity141 requirements. All cultures except @entity15898 A3c grew when repeatedly transferred in a medium without added @entity141 . As @entity141 concentration increased in cellobiose medium, the rate of growth increased and lag time decreased for @entity15898 A3c, whereas @entity26977 exhibited increases in both maximum growth and rate of growth. No responses in any of the criteria were observed for the ruminococci in cellobiose medium. Both strains of @entity15898 had an absolute requirement for @entity141 with cellulose as the only substrate. For @entity13330 c the requirement was 0.36 to 0.42 mM and for S85, >0.64 mM. Increases in extent of cellulose degradation occurred with all strains of ruminococci as @entity141 concentration increased; however, degradation in @entity141 -free medium was similar to that of @entity15898 with @entity141 . Although the ruminococci presumably have cellulosomes that require @entity141 in their structure, such was not evident in our studies. The function of @entity141 in cellulose degradation by @entity15898 is unknown, but may be related to the secretion or activation of their cellulolytic enzymes. Based on reported concentrations of @entity141 in the rumen, it seems unlikely that an in @entity8379 would occur for these bacteria.
