title: High-level production of a thermoacidophilic beta-glucosidase from Penicillium citrinum YS40-5 by solid-state fermentation with rice bran.
abstract: A high yield of beta-glucosidase (EC 3.2.1.21) of 159.1 U/g-solid activity on 4-nitrophenyl beta-d-glucopyranoside (pNPG) was achieved by rice bran-based solid-state fermentation (SSF) of the recently characterized fungus Penicillium citrinum YS40-5. The enzyme was both thermophilic and acidophilic at the optimized temperature and pH of 70 degrees C and 5.0, respectively. Over 95% of the original beta-glucosidase activity was maintained after a prolonged storage at ambient temperature for 4 weeks. The kinetic parameters V(max), K(m) and K(I) were 85.93 U/mg, 1.2 mM and 17.59 mM with pNPG, and 72.49 U/mg, 32.17 mM and 8.29 mM with cellobiose, respectively. The protein band with beta-glucosidase activity was characterized by native PAGE followed by MUG-zymogram analysis, and its identity confirmed by nanoLC-MS/MS. A 3.43-fold synergistic effect by combining this beta-glucosidase with Trichoderma reesei cellulases was observed, indicating this enzyme could potentially be used for improving the efficiency of cellulosic bioconversion.
authors.affiliation: Biotechnology Center in Southern Taiwan, Academia Sinica, 2F, No. 22, Lane 31, Sec. 1, Huandong Rd., Sinshih Township, Tainan 74146, Taiwan, ROC.
authors.forename: I-Son
authors.initials: IS
authors.lastname: Ng
authors.forename: Chen-Wei
authors.initials: CW
authors.lastname: Li
authors.forename: Shuang-Pi
authors.initials: SP
authors.lastname: Chan
authors.forename: Jiun-Ly
authors.initials: JL
authors.lastname: Chir
authors.forename: Po Ting
authors.initials: PT
authors.lastname: Chen
authors.forename: Chii-Gong
authors.initials: CG
authors.lastname: Tong
authors.forename: Su-May
authors.initials: SM
authors.lastname: Yu
authors.forename: Tuan-Hua David
authors.initials: TH
authors.lastname: Ho
mesh_terms: D000595:Amino Acid Sequence; D001709:Biotechnology / Q000379:methods*; D002244:Carbon / Q000494:pharmacology; D002482:Cellulose / Q000378:metabolism; D004275:DNA, Ribosomal / Q000235:genetics; D004795:Enzyme Stability / Q000187:drug effects; D005285:Fermentation / Q000187:drug effects / Q000502:physiology*; D005960:Glucosides / Q000378:metabolism; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D006923:Hymecromone / Q000031:analogs & derivatives / Q000378:metabolism; D007477:Ions; D007700:Kinetics; D013058:Mass Spectrometry; D008670:Metals / Q000494:pharmacology; D008969:Molecular Sequence Data; D009584:Nitrogen / Q000494:pharmacology; D012275:Oryza / Q000378:metabolism*; D010407:Penicillium / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D010802:Phylogeny; D013696:Temperature; D014242:Trichoderma / Q000187:drug effects / Q000201:enzymology; D001617:beta-Glucosidase / Q000096:biosynthesis* / Q000737:chemistry
chemical_list: D004275:DNA, Ribosomal; D005960:Glucosides; D007477:Ions; D008670:Metals; C014110:4-methylumbelliferyl glucoside; D006923:Hymecromone; D002244:Carbon; D002482:Cellulose; D001617:beta-Glucosidase; D009584:Nitrogen