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Characterization of Pantoea dispersa UQ68J: producer of a highly efficient sucrose isomerase for isomaltulose biosynthesis
Author(s) -
Wu L.,
Birch R.G.
Publication year - 2004
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2004.02274.x
Subject(s) - klebsiella oxytoca , pantoea , sucrose , biochemistry , pantoea agglomerans , bacteria , isomerase , biology , chemistry , food science , escherichia coli , enzyme , klebsiella pneumoniae , 16s ribosomal rna , genetics , gene
Aims: Isolation, identification and characterization of a highly efficient isomaltulose producer. Methods and Results: After an enrichment procedure for bacteria likely to metabolize isomaltulose in sucrose‐rich environments, 578 isolates were screened for efficient isomaltulose biosynthesis using an aniline/diphenylamine assay and capillary electrophoresis. An isolate designated UQ68J was exceptionally efficient in sucrose isomerase activity. Conversion of sucrose into isomaltulose by UQ68J (enzyme activity of 90–100 U mg −1 DW) was much faster than the current industrial strain Protaminobacter rubrum CBS574.77 (41–66 U mg −1 DW) or a reference strain of Erwinia rhapontici (0·3–0·9 U mg −1 DW). Maximum yield of isomaltulose at 78–80% of supplied sucrose was achieved in less than half the reaction time needed by CBS574.77, and the amount of contaminating trehalulose (4%) was the lowest recorded from an isomaltulose‐producing microbe. UQ68J is a Gram negative, facultatively anaerobic, motile, noncapsulate, straight rod‐shaped bacterium producing acid but no gas from glucose. Based on 16S rDNA analysis UQ68J is closest to Klebsiella oxytoca , but it differs from Klebsiella in defining characteristics and most closely resembles Pantoea dispersa in phenotype. Significance and Impact of Study: This organism is likely to have substantial advantage over previously characterized sucrose isomerase producers for the industrial production of isomaltulose.