Identification and Regulation of Cellulases within Novel Anaerobic Gut Fungi
EMSL Project ID
48080
Abstract
Biofuels derived from plant biomass (lignocellulose) are attractive alternatives to petroleum-based products, as they avoid many of the economic and environmental problems that plague traditional energy sources. Breakdown of plant waste into simple sugars would translate into the production of renewable fuels via microbial fermentation. However, existing technologies are insufficient to allow for industrial-scale production of these products due to difficulties associated with the recalcitrance of crude lignin-rich biomass, and the high cost/poor performance of known cellulolytic enzymes (cellulases). Therefore, there is a critical need to develop new technologies to break down lignocellulosic biomass into fermentable sugars for downstream fuel development. Towards this goal, much can be learned by studying how anaerobic gut fungi depolymerize lignocellulose in biomass-rich environments, such as the digestive tract of large herbivores. Anaerobic gut fungi are native to the gut and rumen of these animals, where they have evolved unique abilities to break down lignocellulosic biomass through invasive growth and the secretion of powerful enzymes and enzyme complexes (cellulosomes). Towards engineering gut fungi as novel platform organisms for biofuel production, this proposal requests the use of sequencing facilities at the DOE-JGI to sequence genomes and construct de novo transcriptomes from three novel gut fungal isolates (Neocallimastix sp G1, Neocallimastix sp S3, and Anaeromyces sp S4). Each of these isolates thrives on lignocellulosic substrates, and secretes multi-protein cellulosome complexes of cellulases, hemicellulases, and cellulose binding domains. Therefore, transcriptomic and genomic characterization is likely to reveal hundreds of novel enzymes that are useful for biomass breakdown. In effort to determine the basic metabolic networks that govern biomass hydrolysis within anaerobic fungi, we plan to employ RNAseq experiments to quantify transcript abundance when simple sugars repress lignocellulosic degradation. Finally, we aim to employ proteomic studies via mass spectrometry at the EMSL to compare the regulation of secreted fungal enzymes with those regulated at the transcriptional level. Through these efforts, we aim to determine how important enzyme groups are coordinated during biomass breakdown across several fungal genera. Collectively, this information will establish the molecular framework for anaerobic fungal hydrolysis, and will guide in the development of lignocellulosic biofuels.
Project Details
Project type
FICUS Research
Start Date
2013-10-01
End Date
2015-12-31
Status
Closed
Released Data Link
Team
Principal Investigator