title: Purification and characterization of a highly efficient calcium-independent α-amylase from Talaromyces pinophilus 1-95.
abstract: Alpha-amylase is a very important enzyme in the starch conversion process. Most of the α-amylases are calcium-dependent and exhibit poor performance in the simultaneous saccharification and fermentation process of industrial bioethanol production that uses starch as feedstock. In this study, an extracellular amylolytic enzyme was purified from the culture broth of newly isolated Talaromyces pinophilus strain 1-95. The purified amylolytic enzyme, with an apparent molecular weight of 58 kDa on SDS-PAGE, hydrolyzed maltopentaose, maltohexaose, and maltoheptaose into mainly maltose and maltotriose and minor amount of glucose, confirming the endo-acting mode of the enzyme, and hence, was named Talaromyces pinophilus α-amylase (TpAA). TpAA was most active at pH 4.0-5.0 (with the temperature held at 37°C) and 55°C (at pH 5.0), and stable within the pH range of 5.0-9.5 (at 4°C) and below 45°C (at pH 5.0). Interestingly, the Ca2+ did not improve its enzymatic activity, optimal temperature, or thermostability of the enzyme, indicating that the TpAA was Ca2+-independent. TpAA displayed higher enzyme activity toward malto-oligosaccharides and dextrin than other previously reported α-amylases. This highly active Ca2+-independent α-amylase may have potential applications in starch-to-ethanol conversion process.
authors: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China.
authors: Liang
authors: L
authors: Xian
authors: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China.
authors: Fei
authors: F
authors: Wang
authors: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China.
authors: Xiang
authors: X
authors: Luo
authors: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China.
authors: Yu-Liang
authors: YL
authors: Feng
authors: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China.
authors: Jia-Xun
authors: JX
authors: Feng
mesh_terms: D000688:Amylose / Q000378:metabolism; D002118:Calcium / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007477:Ions; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D012995:Solubility; D012997:Solvents / Q000494:pharmacology; D013379:Substrate Specificity / Q000187:drug effects; D032901:Talaromyces / Q000166:cytology / Q000201:enzymology*; D013696:Temperature; D000516:alpha-Amylases / Q000302:isolation & purification* / Q000378:metabolism*
chemical_list: D007477:Ions; D012997:Solvents; D000688:Amylose; D000516:alpha-Amylases; D002118:Calcium