title: Effects of granule swelling on starch saccharification by granular starch hydrolyzing enzyme.
abstract: The effects of granule swelling on enzymatic saccharification of normal corn starch by granular starch hydrolyzing enzyme were investigated. After swelling, Km values for the saccharification of granular starch decreased compared with native granular starch, indicating that granule swelling caused granular starch hydrolyzing enzyme to have higher affinity for starch granules. The partial swelling of starch granules enhanced starch saccharification. Furthermore, the enhancement at an earlier stage of enzymatic reaction was much more significant than that at later stages. For granular starch pretreated at 67.5 °C for 30 min, conversions to glucose after incubation with the enzyme at 32 °C for 4 and 24 h were approximately 3-fold and 26% higher than for native granular starch, respectively. As a result, proper heat pretreatment of granular starch before simultaneous saccharification and fermentation has great potential to facilitate industrial production of ethanol by use of granular starch hydrolyzing enzyme.
authors.affiliation: Department of Grain Science and Industry, Kansas State University , Manhattan, Kansas 66506, United States.
authors.forename: Zhaofeng
authors.initials: Z
authors.lastname: Li
authors.forename: Liming
authors.initials: L
authors.lastname: Cai
authors.forename: Zhengbiao
authors.initials: Z
authors.lastname: Gu
authors.forename: Yong-Cheng
authors.initials: YC
authors.lastname: Shi
mesh_terms: D001230:Aspergillus / Q000201:enzymology; D056804:Biofuels / Q000191:economics; D003246:Conservation of Energy Resources; D004795:Enzyme Stability; D000431:Ethanol / Q000191:economics / Q000378:metabolism; D005285:Fermentation; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism*; D005087:Glucan 1,4-alpha-Glucosidase / Q000737:chemistry / Q000378:metabolism*; D005947:Glucose / Q000032:analysis / Q000378:metabolism; D006358:Hot Temperature; D006868:Hydrolysis; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D012639:Seeds / Q000737:chemistry*; D013213:Starch / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D013499:Surface Properties; D014867:Water / Q000032:analysis*; D003313:Zea mays / Q000737:chemistry*; D000516:alpha-Amylases / Q000737:chemistry / Q000378:metabolism*
chemical_list: D056804:Biofuels; D005656:Fungal Proteins; D014867:Water; D000431:Ethanol; D013213:Starch; D000516:alpha-Amylases; D005087:Glucan 1,4-alpha-Glucosidase; D005947:Glucose