Exploiting Anaerobes for Biomass Breakdown and Sustainable Chemistry
Abstract
Renewable chemicals derived from plant biomass (mainly
composed of cellulose and lignin) are attractive alternatives to
those made from petroleum. To produce chemicals from biomass,
enzymes are used to break down cellulose into simple sugars,
which are later fermented into value-added products. However,
since cellulose is tightly bound within a network of crystalline
cellulosic fibers and lignin, existing biomass degrading enzymes
are not very efficient. To develop new technologies to break down plant material into
sugar, much can be learned by studying how microbes digest
lignocellulose in biomass-rich environments, such as the digestive
tract of large herbivores. Anaerobic fungi are native to the gut and
rumen of these animals, where they have evolved powerful
enzymes to degrade plant biomass. Our goal is to develop new
experimental tools to engineer anaerobic fungi and anaerobic
microbial consortia for lignocellulose breakdown and chemical
production. To accomplish this goal, we isolated a panel of
anaerobic fungi and associated microbes from different herbivores
and screened for their ability to degrade several types of lignin-rich grasses and agricultural waste. By focusing on model anaerobic fungi from the Piromyces,
Neocallimastix, and Anaeromycesgenera, we have employed next-generation sequencing to discover thousands of new
genes, revealing hundreds of novel cellulases.
Additionally, we have characterized key regulatory patterns for these cellulases, which depend on the environment of the
fungus. Using this information, we are developing new genetic engineering strategies to manipulate gut fungi at the
molecular level, along with 'bottom-up' strategies to synthesize microbial consortia for compartmentalized breakdown and
bioproduclion.