Open AccessAdaptation of Ruminococcus flavefaciens resulting in increased degradation of ryegrass cell walls
Author(s) -
Saluzzi Liliana,
Flint Harry J.,
Stewart Colin S.
Publication year - 2001
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.2001.tb00833.x
Subject(s) - biology , xylanase , rumen , xylose , ruminococcus , bacteria , strain (injury) , cell wall , microbiology and biotechnology , food science , biochemistry , enzyme , fermentation , genetics , anatomy
This study investigated the long term adaptation of a ruminal bacterium to growth on four different plant cell wall substrates. No significant increase in degradation was detected for lucerne, barley straw or weeping lovegrass after 23 serial subcultures of the cellulolytic rumen bacterium Ruminococcus flavefaciens strain 17 on each of these substrates. Significantly increased substrate degradation by R. flavefaciens strain 17 was however observed after 23 subcultures on perennial ryegrass. The increase in dry matter solubilisation (from 24.3 to 39.5% in 24 h incubation and from 52.3 to 61% in 72 h) was at least partially due to an increase in solubilisation of xylose, glucose and arabinose. Enhanced growth of the adapted strains occurred on this substrate. Significant increases in xylanase and β‐xylosidase specific activities were detected but no effect was detected on xylanase profiles in zymogram analyses. Similar responses were observed for two cultures originally derived from single‐colony re‐isolates. The most likely explanation for the observed adaptation involves selection for mutations affecting the regulation of xylanolytic enzymes.