(609g) Unlocking the Potential of the Animal Mycobiome for Bioenergy and Animal Health

Authors: 
Solomon, K. V. - Presenter, University of California, Santa Barbara
Complex microbiomes within the digestive tract of herbivores are increasingly of interest for the discovery of novel lignocellulose degrading enzymes and biocatalysts for the production of biofuels. Central to this community are anaerobic fungi, which are prolific digesters of crude lignocellulose through a combination of powerful secreted enzymes and invasive growth. Despite their outsize contributions to digestion in large herbivores, the mycobiome has historically been overlooked due to its low abundance within the microbiome. Here, we enrich for these fungi and pursue a multi –omics approach integrated with biochemical characterization, growth phenotypes, and heterologous expression to probe the catalytic potential of these overlooked organisms for bioenergy and improved animal health. We have assembled a panel of novel fungal isolates from both zoo and farm animals representing several types of fungal genera. We demonstrate that these fungi express and secrete tightly regulated carbohydrate active enzymes (e.g. cellulases) that are active on a broad array of untreated agricultural residues, food wastes, and woody forestry products. More importantly, these enzymes are robust against increasing levels of syringyl lignin, which is a natural plant defense against microbial degradation. Thus, these anaerobic fungi have significant potential to pretreat diverse and difficult lignocellulosic feedstocks for bioenergy production without enzyme supplementation from other organisms. Also encoded within the genomes of these organisms are large reservoirs of natural product gene clusters that rival those of super-producing actinomycetes. These natural products are hypothesized to mediate microbiome function, and thus animal health, and offer potentially novel biocatalytic routes to advanced biofuels and medicines. We are currently validating these clusters and characterizing their products and regulation through metabolomics and co-culturing studies. Our ongoing efforts suggest that the animal mycobiome is a rich untapped reservoir for bioenergy, and provides a roadmap for its application in diverse engineering efforts.