Anaerobic fungi reside in the gut of herbivore and synergize with associated methanogenic archaea to decompose ingested plant biomass. Despite their potential for use in bioconversion industry, only a few natural fungus-methanogen co-cultures have been isolated and characterized. In this study we identified three co-cultures of Piromyces with Methanobrevibacter ruminantium from the rumen of yaks grazing on the Qinghai Tibetan Plateau. The representative co-culture, namely (Piromyces + M. ruminantium) Yak-G18, showed remarkable polysaccharide hydrolase production, especially xylanase. Consequently, it was able to degrade various lignocellulose substrates with a biodegrading capability superior to most previously identified fungus or fungus-methanogen co-culture isolates. End-product profiling analysis validated the beneficial metabolic impact of associated methanogen on fungus as revealed by high-yield production of methane and acetate and sustained growth on lignocellulose. Together, our data demonstrated a great potential of (Piromyces + M. ruminantium) Yak-G18 co-culture for use in industrial bioconversion of lignocellulosic biomass.
Keywords: Anaerobic fungus; Bioconversion; Lignocellulose; Methanogen; Yak.