Characterization of acid-stable glucose isomerase from Streptomyces sp., and development of single-step processes for high-fructose corn sweetener (HFCS) production.
The glucose isomerase from Streptomyces olivaceoviridis E-86 was purified by chromatographic procedures, showing one single protein band in the SDS-PAGE. The enzyme had high acid stability, and there was no loss in enzyme activity at pH 5.0 after incubation at 60 degrees C for 30 hr. The enzyme had sufficients activity at 60 degrees C, pH 5.5, (which is the reaction condition for a single-step process with a glucoamylase from A. niger), and at 58 degrees C, pH 6.0, (condition with a glucoamylase from R. niveus). By using this acid-stable glucose isomerase, a single-step process to produce high-fructose corn sweetener (HFCS) from liquefied starch was formed without any reductant or other reagents for enzyme stabilization. The HFCS produced was about fifty percent fructose and less than 1.5% unknown oligosaccharides.
Kaneko
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T
Department of Bioengineering, Akita Research Institute of Food and Brewing, Arayamachi, Japan. kaneko@sake.arif.pref.akita.jp
Takahashi
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S
Saito
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K
D019747:Aldose-Ketose Isomerases / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D000595:Amino Acid Sequence; D004795:Enzyme Stability; D005524:Food Technology; D005632:Fructose / Q000096:biosynthesis*; D006863:Hydrogen-Ion Concentration; D016415:Sequence Alignment; D013213:Starch / Q000378:metabolism; D013302:Streptomyces / Q000201:enzymology* / Q000235:genetics; D013549:Sweetening Agents / Q000138:chemical synthesis*; D013696:Temperature; D003313:Zea mays / Q000737:chemistry
D013549:Sweetening Agents; D005632:Fructose; D013213:Starch; D019747:Aldose-Ketose Isomerases; C023298:xylose isomerase