Scientists Discover Novel Biomass-Degrading Enzymes from Horse Gut Fungus

Scientists from the USA have reported the isolation of a new fungal species from a horse's digestive tract  which exhibited high enzymatic activity against cellulose and lignocelluloses materials.

The enzymatic breakdown of cellulose intermeshed with the tough lignin polymer in biomass feedstock is a bottleneck in biofuel conversion. Researchers have turned to the digestive systems of large herbivores like cows and horses in search for microbial enzymes that can efficiently degrade the cellulose and lignocellulose substrates into simple sugars to be fermented into ethanol. Previous investigations have focused on gut bacteria, but researchers believe that gut fungi represent an important source of robust cellulose digesters that secrete unique and powerful enzyme complexes.

One recent study by researchers at the University of California (UC) Santa Barbara and their collaborators from the Massachusetts Institute of Technology and Harvard University focused on gut fungi living in the intestinal tracts of horses which can digest lignin-rich grasses.

In their report presented at the 245th National Meeting & Exposition of the American Chemical Society, the researchers described the isolation of a new species of anaerobic gut fungus and the subsequent discovery of novel biomass-degrading or "cellulolytic" enzymes that it produces. By analyzing the fungus's transcriptome - the collection of protein-encoding genetic material – the research team was able to directly identify and assemble the genes coding for enzymes capable of breaking down cellulose and lignocelluloses substrates. The team is now seeking to identify from this collection the most active enzymes and to transfer the fungal genes that produce such enzymes to yeasts for large-scale industrial production.