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|Type:||Artigo de periódico|
|Title:||Characterization Of A Glucosyltransferase From Erwinia Sp. D12 And The Conversion Of Sucrose Into Isomaltulose By Immobilized Cells|
|Abstract:||Erwinia sp. D12 is able to produce an isomaltulose synthase (EC 220.127.116.11) that converts sucrose into isomaltulose. The enzyme was partially purified using a two-step chromatographic process on DEAE-Sephadex A-50 and DEAE-Sepharose CL-6B. The molecular mass of 63 kDa was estimated by Sephadex G-200 gel filtration, and the K m and V max values determined for the enzyme were 138 mM and 9.81 μmol/min/mg protein with sucrose as the substrate, respectively. Enzyme activity was optimal at pH 6.0 and 40 °C. The glucosyltransferase was completely inhibited by Hg 2+ and Ag +. An experimental design and response surface methodology were used to evaluate the influences of temperature, pH and substrate concentration on isomaltulose production from cells immobilized in chitosan. With the aid of a two-level full factorial design (2 3-FFD), the statistical analysis of the results showed that, in the range studied, the factors had a significant (p < 0.05) effect on isomaltulose production. The conditions that improved isomaltulose production were: temperature around 35 °C, pH 6.0 and sucrose concentration lower than 40%. © 2009 Elsevier B.V. All rights reserved.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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