(633a) Fire-Adapted Microbes

Efforts to convert plant biomass into fuels and other bio-based products are increasingly focusing on thermal methods. These methods offer several key advantages over enzymatic deconstruction routes, including being ‘agnostic’ to the type of biomass being treated. Heat-modified residues, however, still require enzymatic processing, and current enzyme ‘cocktails’ are not optimized to these tasks. These residues may also contain lignin residues that repolymerize after initial depolymerization, a chemical process that in nature can be overcome biochemically via oxidative enzymes such as peroxidases. Our goal is to identify and validate novel biomanufacturing enzymes from a logical organism source - fire-adapted microbes.

Fungi are perhaps the most well-studied examples of fire-adapted microbes, and an outstanding example is Neurospora crassa. This Ascomycete fungus has been co-opted by those studying the gene-for-enzyme theory as a model system for genetic recombination, using its easily-counted melanized spores. This fungus has also been a key model system for studying circadian rhythms, tracking daily sporulation ‘rings’ not controlled by light. Neurospora has become an enzyme toolkit for studying its habits out of the context of its natural niche on fire-killed plant biomass. This essentially leaves a treasure trove of genetics tools disconnected to a key trait of the fungus, and the gains in unlocking this system in context of thermal deconstruction routes look very promising. There are also other fungal genera (e.g. Gloeophyllum, Schizophyllum, Antrodia) associated with fire, many of which have newly-annotated genomes in the Joint Genome Institute portal, and elsewhere.

Tapping into these fire-adapted microbial systems may reveal genes with more relevance to thermal deconstruction processes and with more potential for tailoring to biomanufacturing processes ‘downstream.’ Specifically, these pathways may be more efficient than current cocktails in their hydrolysis of anhydro oligomers, detoxification of thermally-derived fermentation inhibitors (e.g. acetate), and stabilization of solubilized lignin. Traditional cocktail enzymes were not designed for this job, and their catalytic domains did not evolve on thermally-modified substrates such as levoglucosan. Fire-adapted fungi are a logical prospect to address these needs. Given the range of possibilities for fire-adapted microbes, my talk will present the range and traits of these uniquely-adapted organisms, and the genomic toolkits for tapping into their biotechnologically-relevance capacities going forward.