Submitted to: Microbial Ecology International Symposium
Publication Type: Abstract Only
Publication Acceptance Date: August 14, 1998
Publication Date: N/A
Technical Abstract: After cellulose, xylans are the most abundant plant cell wall polysaccharides. Xylans are readily fermented in anaerobic microbial ecosystems and, therefore, might serve as rich sources of microorganisms capable of fermenting this substrate. Xylan fermenting ruminal bacteria were isolated from enrichment cultures containing corn fiber xylan (CFX). One isolate, strain RZ, was able to grow rapidly on CFX, utilizing greater than 90% of the substrate in less than 24 h. Strain RZ is a strictly anaerobic, Gm , pleomorphic rod-shaped bacterium similar to Prevotella ruminicola. However, analysis of the DNA sequence of the 16S rRNA gene indicated that strain RZ possessed about 87% sequence identity with the type strain of P. ruminicola. In addition to CFX, strain RZ also utilized a variety of low molecular weight (MW) xylans and arabinans but used larger MW polysaccharides poorly. Xylanolytic enzymes appear to be located in the periplasm, and this might be responsible for differences in the substrate utilization patterns observed.