1997 Fiscal Year Final Research Report Summary
Development of Fields for Enzymatic Reaction Using Grafted Polymer Chains Immobilizing Enzyme at a High Density
| Project/Area Number |
07555253
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
生物・生体工学
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| Research Institution | Chiba University |
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Principal Investigator |
SAITO Kyoichi Chiba University, Department of Engineering, Associate Professor, 工学部, 助教授 (90158915)
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| Project Period (FY) |
1995 – 1997
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| Keywords | enzyme / amylase / starch hydrolysis / porous membrane / hollow fiber / radiation-induced graft polymerization / grafted polymer chain / fast reaction |
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| Research Abstract |
Extensive research has been carried out on immobilized enzymes because recovery of expensive enzymes after reactions with substrates is not required. Entrapping enzymes in a gel matrix, for example, in a caragenan gel, is a representative immobilization method where the substrate is required to diffuse into the gel to reach the active site of the immobilized enzyme. When an intrinsic reaction rate is fast, the overall reaction rate is governed by the diffusion rate of the substrate into the gel. A convection-aided reaction system using an enzyme immobilized on a porous membrane will realize a higher throughput, because the diffusional path of the substrate to the enzyme can be minimized.
The objective of our study was to evaluate a high performance enzyme reaction system using a porous hollow-fiber membrane containing a polymer chain grafted on the pore surface. Here, alpha-amylase was bound by a phenyl group introduced onto the graft chain, and starch was used as a substrate.
A phenyl group was introduced onto the polymer chain grafted onto a porous hollow-fiber membrane to bind alpha-amylase. The resulting phenyl-group-containing porous membrane (Ph fiber) had inner and outer diameters of 0.73 and 1.45 mm, respectively. An alpha-amylase solution was forced to permeate radially outward through the pores of the Ph fiber. The amount of alpha-amylase immobilized was 12 mg per g of the Ph fiber. Quantitative hydrolysis of starch during permeation of a 20 g/L starch solution in buffer (0.010 M Tris-HCl + 0.10 M CaCl_2, pH 7) was attained up to a space velocity of 2,200 h^<-1> ; this was achieved at an operating pressure of 0.15 MPa because of negligible diffusional mass-transfer resistance of the starch to the alpha-amylase due to convective flow. Although the activity of alpha-amylase was lowered to 10% by immobilization, the stability of alpha-amylase captured by the graft chain was higher than that of soluble alpha-amylase.
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Research Products
(12 results)
