Sugar and polysaccharide fermentation by rumen anaerobic fungi from Australia, Britain and New Zealand

Abstract

Nine strains of anaerobic fungi, assigned to the genera Neocallimastix and Piromonas, have been isolated from samples of ruminal digesta obtained from sheep and cattle in temperate Australia. Two strains of Sphaeromonas were also isolated from sheep. The patterns of utilization of mono-, oligo- and polysaccharides were determined for these fungi, four Neocallimastix spp. from Britain and New Zealand, and two Piromonas spp. from Britain. All 17 strains utilized cellobiose, fructose, gentiobiose, glucose and lactose. The seven Neocallimastix spp., whether from sheep or cattle, also fermented cellulose, glycogen, inulin, maltose, raffinose, starch, sucrose, xylan and xylose. Both Sphaeromonas isolates also fermented xylan and xylose. The eight Piromonas strains displayed a diversity in carbohydrate utilization, and could not be formed into a cohesive group. The metabolic endproducts of one strain each of Neocallimastix, Sphaeromonas and Piromonas were determined. They all produced acetate, formate, D(-)-lactate, ethanol and CO2 during glucose fermentation.