Effect of cocultivation of ruminal chytrid fungi with Methanobrevibacter smithii on lucerne stem degradation and extracellular fungal enzyme activities

Pentoses and hexoses were removed simultaneously from lucerne (Medicago sativa) stem by Piromonas communis and Neocallimastix frontalis growing axenically or in coculture with Methanobrevibacter smithii. In monocultures, more arabinose (68–71%) than glucose (52–53%) or xylose (25–30%) was removed. In cocultures, xylose solubilization from cell walls increased for P. communis whereas glucose solubilization increased for both fungi. The rates of sugar removal were monosaccharide-dependent. For both fungi, the specific activities of extracellular hydrolytic enzymes were markedly elevated in methanogenic cocultures.