title: A Novel Acid-Stable Endo-Polygalacturonase from Penicillium oxalicum CZ1028: Purification, Characterization, and Application in the Beverage Industry.
abstract: Acidic endo-polygalacturonases are the major part of pectinase preparations and extensively applied in the clarification of fruits juice, vegetables extracts, and wines. However, most of the reported fungal endo-polygalacturonases are active and stable under narrow pH range and low temperatures. In this study, an acidic endo-polygalacturonase (EPG4) was purified and characterized from a mutant strain of Penicillium oxalicum. The N-terminal amino acid sequence of EPG4 (ATTCTFSGSNGAASASKSQT) was different from those of reported endopolygalacturonases. EPG4 displayed optimal pH and temperature at 5.0 and 60-70°C towards polygalacturonic acid (PGA), respectively, and was notably stable at pH 2.2-7.0. When tested against pectins, EPG4 showed enzyme activity over a broad acidic pH range (>15.0% activity at pH 2.2-6.0 towards citrus pectin; and >26.6% activity at pH 2.2-7.0 towards apple pectin). The Km and Vmax values were determined as 1.27 mg/ml and 5,504.6 U/mg, respectively. The enzyme hydrolyzed PGA in endo-manner, releasing oligo-galacturonates from PGA, as determined by TLC. Addition of EPG4 (3.6 U/ml) significantly reduced the viscosity (by 42.4%) and increased the light transmittance (by 29.5%) of the papaya pulp, and increased the recovery (by 24.4%) of the papaya extraction. All of these properties make the enzyme a potential application in the beverage industry.
authors.affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, P.R. China.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Cheng
authors.affiliation: National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning 530007, P.R. China.
authors.forename: Dong
authors.initials: D
authors.lastname: Chen
authors.affiliation: National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning 530007, P.R. China.
authors.forename: Bo
authors.initials: B
authors.lastname: Lu
authors.affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, P.R. China.
authors.forename: Yutuo
authors.initials: Y
authors.lastname: Wei
authors.affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, P.R. China.
authors.forename: Liang
authors.initials: L
authors.lastname: Xian
authors.affiliation: National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning 530007, P.R. China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.affiliation: Guangxi Zhuang Autonomous Region Institute of Supervision and Testing on Product Quality, Nanning 530007, P.R. China.
authors.forename: Zhenzhen
authors.initials: Z
authors.lastname: Luo
authors.affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, P.R. China.|National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning 530007, P.R. China.
authors.forename: Ribo
authors.initials: R
authors.lastname: Huang
mesh_terms: D000595:Amino Acid Sequence; D029441:Carica / Q000378:metabolism; D003001:Cloning, Molecular; D003080:Cold Temperature; D004795:Enzyme Stability; D000067030:Fruit and Vegetable Juices / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009154:Mutation; D010368:Pectins; D010407:Penicillium / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D011096:Polygalacturonase / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D016415:Sequence Alignment; D013696:Temperature; D014920:Wine / Q000032:analysis
chemical_list: D010368:Pectins; D011096:Polygalacturonase
keywords: Penicillium oxalicum; acid-stablity; application; endo-polygalacturonase; purification