Jessy Gonzalez

ANAEROBIC GUT FUNGI: ADVANCES IN HETEROLOGOUS GENE EXPRESSION

Jessy Gonzalez, Tejas Navaratna, Michelle O'Malley

The microbial gut communities in ruminants and monogastric herbivores can convert lignocellulosic material at a yield and rate that surpasses our best lignocellulosic biorefineries. The anaerobic gut fungi (AGF) or Neocallimastigomycetes, are considered the primary colonizers of ingested plant biomass and contribute significantly in converting lignocellulose into fermentable sugars via a large collection of cellulolytic enzymes, enzyme complexes, and secondary metabolites. AGF have demonstrated the potential utilization of lignocellulosic hydrolysates to produce biotechnologically valuable products, including short- and medium-chain fatty acids and antimicrobial peptides. However, despite their proficient depolymerization processes, the genetic characterization of these enzymes and natural products remains poorly understood. Currently, it is a challenge to characterize the genomes of anaerobic fungi because of anaerobic environment constraints and a lack of effective genome editing strategies. This presentation will report efforts to establish an efficient heterologous gene expression tool for Neocallimastix californiae. We have identified strong anaerobic fungal promoters via a yeast-based expression system, and are testing these for hygromycin resistance expression in AGF. Furthermore, we are actively optimizing transformation systems to improve cellular viability in AGF zoospores. If successful, such findings may increase our understanding of refining lignocellulose into value-added chemicals and expand the genetic tools available to other non-model microbes.