title: Driving biomass breakdown through engineered cellulosomes.
abstract: Extraction of sugar is the rate-limiting step in converting unpretreated biomass into value-added products through microbial fermentation. Both anaerobic fungi and anaerobic bacteria have evolved to produce large multi-cellulase complexes referred to as cellulosomes, which are powerful machines for biomass deconstruction. Characterization of bacterial cellulosomes has inspired synthetic "designer" cellulosomes, consisting of parts discovered from the native system that have proven useful for cellulose depolymerization. By contrast, the multi-cellulase complexes produced by anaerobic fungi are much more poorly understood, and to date their composition, architecture, and enzyme tethering mechanism remain unknown and heavily debated. Here, we compare current knowledge pertaining to the cellulosomes produced by both bacteria and fungi, including their application to synthetic enzyme-tethered systems for tunneled biocatalysis. We highlight gaps in knowledge and opportunities for discovery, especially pertaining to the potential of fungal cellulosome-inspired systems.
authors.affiliation: a Department of Chemical Engineering ; University of California ; Santa Barbara , CA USA.
authors.forename: Sean P
authors.initials: SP
authors.lastname: Gilmore
authors.forename: John K
authors.initials: JK
authors.lastname: Henske
authors.forename: Michelle A
authors.initials: MA
authors.lastname: O'Malley
mesh_terms: D001419:Bacteria / Q000737:chemistry / Q000201:enzymology; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D055162:Biocatalysis; D057005:Bioengineering; D018533:Biomass; D044602:Cellulases / Q000737:chemistry* / Q000378:metabolism; D002482:Cellulose / Q000737:chemistry* / Q000378:metabolism; D044603:Cellulosomes / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D005285:Fermentation; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism; D005658:Fungi / Q000737:chemistry / Q000201:enzymology; D005947:Glucose / Q000096:biosynthesis* / Q000737:chemistry; D006026:Glycoside Hydrolases / Q000737:chemistry* / Q000378:metabolism; D006868:Hydrolysis; D009097:Multienzyme Complexes / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D001426:Bacterial Proteins; D005656:Fungal Proteins; D009097:Multienzyme Complexes; D002482:Cellulose; D044602:Cellulases; D006026:Glycoside Hydrolases; D005947:Glucose
keywords: CBM, Carbohydrate Binding Module; ELISA, Enzyme-Linked Immunosorbent Assay; GH, Glycoside Hydrolase; GST, Glutathione S-Transferase; SLH, Surface Layer Homology; anaerobic fungi; biofuels; cellulase; cellulosome; lignocellulose