title: Identification of novel bacterial expansins and their synergistic actions on cellulose degradation.
abstract: Novel expansins, non-catalytic proteins which induce weakening of the rigid cellulose structure, have been identified in this study. A pipeline of bioinformatics was implemented for sequence and structure-based prediction of putative bacterial expansin-like group × family from NR databases. All putative expansins had no detectable activity against cellulosic and hemicellulosic substrates but showed varying degrees of synergy (2.0-7.6 folds) with the commercial Trichoderma reesei cellulase (Celluclast™ 1.5L) on degradation of filter paper in order of BpEX ≈ CmEX > MaEX > PcEX > SaEX. A mixture design with full cubic model predicted optimal formulation comprising Celluclast™: CmEX from Clavibacter michiganensis = 72.4%: 27.6%, with no synergy of β-glucosidase on degradation of alkaline pretreated rice straw. Under these conditions, the reducing sugar yield was 163.6% compared with the reaction containing cellulase alone. This work demonstrated the potential benefit of novel bacterial expansins on enhancing cellulose degradation efficiency in lignocellulosic biomass degradation.
authors.affiliation: Department of Genetics, Faculty of Sciences, Kasetsart University, Chatuchak, Bangkok 10900, Thailand.
authors.forename: Benjarat
authors.initials: B
authors.lastname: Bunterngsook
authors.affiliation: Enzyme Technology Laboratory, Bioresources Technology Unit, National Center for Genetic Engineering and Biotechnology, Thailand Science Park, Klong Luang, Pathumthani 12120, Thailand.
authors.forename: Wuttichai
authors.initials: W
authors.lastname: Mhuantong
authors.affiliation: Enzyme Technology Laboratory, Bioresources Technology Unit, National Center for Genetic Engineering and Biotechnology, Thailand Science Park, Klong Luang, Pathumthani 12120, Thailand.
authors.forename: Verawat
authors.initials: V
authors.lastname: Champreda
authors.affiliation: Department of Genetics, Faculty of Sciences, Kasetsart University, Chatuchak, Bangkok 10900, Thailand.
authors.forename: Arinthip
authors.initials: A
authors.lastname: Thamchaipenet
authors.affiliation: Enzyme Technology Laboratory, Bioresources Technology Unit, National Center for Genetic Engineering and Biotechnology, Thailand Science Park, Klong Luang, Pathumthani 12120, Thailand. Electronic address: lily@biotec.or.th.
authors.forename: Lily
authors.initials: L
authors.lastname: Eurwilaichitr
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002480:Cellulase / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism*; D019295:Computational Biology; D004591:Electrophoresis, Polyacrylamide Gel; D005798:Genes, Bacterial; D006868:Hydrolysis; D008031:Lignin / Q000378:metabolism; D012044:Regression Analysis; D014242:Trichoderma / Q000201:enzymology
chemical_list: D001426:Bacterial Proteins; C036909:lignocellulose; D002482:Cellulose; D008031:Lignin; D002480:Cellulase
keywords: Cellulase; Expansin; Lignocellulose; Mixture design; Synergy