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  • 1
    Electronic Resource
    Electronic Resource
    Immobilization of the exo-maltohexaohydrolase by the irradiation method (1983)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 25 (1983), S. 1095-1107 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Exomaltohexaohydrolase (E.C.3.2.1.98) was immobilized by radiocopolymerization of some synthetic monomers which were mixed in various combinations. Irradiation was carried out while the mixture of monomers and enzymes was frozen in petroleum ether-dry-ice bath. Recovery of the immobilized enzyme was 44-75%.The optimum pH of the enzyme slightly shifted to the acidic side. The pH stability was improved remarkably by immobilization. The enzyme was stable retaining more than 90% of its original activity in the range pH 4-11. The optimum reaction temperature of the enzyme increased about 2°C. Heat stability was also improved by immobilization, and that the enzyme retained about 40% of its original activity after treatment at 75°C for 15 min. The immobilized enzyme was stable to the repeated use of 20 cycles. The Km value of the enzyme for short-chain amylose was almost the same as that of native enzyme. When soluble starch was used as the substrate, the Km, value of the enzyme was three times as large as that of native enzyme. Effects of various metal ions and inhibitors on the immobilized enzyme were also studied compared to the native enzyme.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260250417
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  • 2
    Electronic Resource
    Electronic Resource
    Continuous production of maltotetraose using immobilized Pseudomonas stutzeri amylase (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 32 (1988), S. 669-676 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A continuous production process of maltotetraose was investigated by using immobilized maltotetraose (G4)- forming amylase (1,4-α-D-glucan maltotetraohydrolase, EC3.2.1.60) from Pseudomonas stutzeri adsorbed on a macroporous hydrophobic resin. The maximum reaction rate was obtained at 55°C and the activation energy of hydrolysis by immobilized G4-forming amylase was calculated to be 8.45 kcal/mol. The maltotetraose yield was greatly influenced by the flow rate of substrate solution, its concentration, and the immobilized enzyme activity. The newly defined factor “specific space velocity” was successfully introduced to normalize the operating parameters. Using this factor, the immobilized enzyme reactor then can be simulated and the operating dynamics can be determined.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260320512
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Stability of immobilized maltotetraose-forming amylase from Pseudomonas stutzeri (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 845-855 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The stability of immobilized maltotetraose (G4)-forming amylase (1,4-α-D-glucan maltoteraohydrolase, EC 3.2.1.60) from Pseudomonas stutzeri was investigated in both batch and continous processes. The inactivation process of the immobilized enzyme seemed to obey first-order kinetics, and the immobilized enzyme became more stable when coexisting with 20-30 wt % substrate and calcium ions. From intensive studies on the operational stability in the continuous process, the apparent half-life of G4 productivity in a constant-flow system was mainly affected by the reaction temperature, substrate concentration, and initial immobilized enzyme activity. A new factor, immobilized enzyme stability factor fs, was proposed to evaluate the half-life of the immobilized enzyme system.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330708
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  • 4
    Electronic Resource
    Electronic Resource
    Continuous production of maltotetraose using a dual immobilized enzyme system of maltotetraose-forming amylase and pullulanase (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 36 (1990), S. 790-796 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In order to produce a product with a high content of maltotetraose, dual-enzyme systems composed of immobilized maltotetraose-forming amylase (G4-forming amylase) and pullulanase were studied. The thermostability of individually immobilized enzymes was examined in continuous operation; studies revealed that the enzyme immobilized on “Chitopearl” was much more stable than that immobilized on Diaion HP-50. The effects of operating conditions on the stability of G4 forming amylase immobilized on “Chitopearl” were examined to confirm that the apparent half-life data could be arranged using the immobilized enzyme stability factor, fs. As for the dual immobilized enzyme system, six methods of usage were considered, with five yielding a 7-10% (w/w) higher content of maltotetraose product than the single-enzyme system. The effects of operating conditions on the maltotetraose production reaction were examined to confirm that the maltotetraose content of the products could be analyzed using the specific space velocity,SSV. In dual immobilized enzyme systems, pullulanase immobilized on the same carrier as the G4-forming amylase was found to be more stable than pullulanase immobilized on separate carriers. The effectiveness of using immobilized pullulanase along with the G4-forming amylase was confirmed from constant-conversion operations in which the maltotetraose content in the product was kept at 50% (w/w) in laboratory-scale experimentation.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260360806
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    Paper (German National Licenses)
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