title: Bi-functional cellulases complexes displayed on the cell surface of Corynebacterium glutamicum increase hydrolysis of lignocelluloses at elevated temperature.
abstract: Introducing cellulases into Corynebacterium glutamicum leads to the direct degradation of lignocellulosic materials for energy sources. In this study, a cellulase complex containing two cellulolytic enzymes, endoglucanase E (CelE) and β-glucosidase A (BglA), was established to completely degrade cellulose to glucose. The cellulases complexes were displayed on the cell surface of C. glutamicum by using the mechanosensitive channel (Msc) to anchor enzymes in the cytoplasmic membrane. As confirmed by comparison enzyme activities in the cell pellet fraction and supernatant and dual color based immunofluorescence microscopy, the cellulolytic enzymes was successfully associated with the cell surface of C. glutamicum. The displayed cellulases complexes had a synergic effect on the direct conversion of biomass to reducing sugars leading to 3.1- to 6.0-fold increase compared to the conversion by the secreted cellulases complexes. In addition, the displayed cellulases complexes increased the residual activities of cCelE and cBglA at 70°C from 28.3% and 24.3% in the secreted form to 65.1% and 82.8%, respectively. The display of cellulases complexes on the cell surface of C. glutamicum enhances the polysaccharide equivalent and the direct saccharification of low cost biomass via the action of multi-thermostable enzyme complexes.
authors.affiliation: Department of Biotechnology, Korea University, Seoul 136-701, Republic of Korea.
authors.forename: Su Jung
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: Department of Biotechnology, Korea University, Seoul 136-701, Republic of Korea.
authors.forename: Jeong Eun
authors.initials: JE
authors.lastname: Hyeon
authors.affiliation: Department of Biotechnology, Korea University, Seoul 136-701, Republic of Korea.
authors.forename: Sang Duck
authors.initials: SD
authors.lastname: Jeon
authors.affiliation: Changhae Advanced Institute of Technology, Changhae Ethanol C., Ltd., Jeonju 561-203, Republic of Korea.
authors.forename: Gi-wook
authors.initials: GW
authors.lastname: Choi
authors.affiliation: Department of Biotechnology, Korea University, Seoul 136-701, Republic of Korea. Electronic address: samhan@korea.ac.kr.
authors.forename: Sung Ok
authors.initials: SO
authors.lastname: Han
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001673:Biodegradation, Environmental; D018533:Biomass; D001709:Biotechnology; D002462:Cell Membrane / Q000201:enzymology; D002480:Cellulase / Q000235:genetics / Q000378:metabolism; D044602:Cellulases / Q000235:genetics / Q000378:metabolism*; D048230:Corynebacterium glutamicum / Q000201:enzymology* / Q000235:genetics; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000235:genetics / Q000378:metabolism; D005959:Glucosidases / Q000235:genetics / Q000378:metabolism; D006868:Hydrolysis; D008031:Lignin / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D004800:Enzymes, Immobilized; D011994:Recombinant Proteins; C036909:lignocellulose; D008031:Lignin; C406205:CelE protein, bacteria; D044602:Cellulases; D005959:Glucosidases; D002480:Cellulase
keywords: Anchoring protein; Cellulases complex; Consolidated bioprocess; Corynebacterium glutamicum; Lignocelluloses degradation; Thermostability