Urease immobilization on chemically grafted nylon membranes

El-Sherif, Hazem; Maio, Anna De; Martino, Silvana; Zito, Edward T.; Rossi, Sergio; Canciglia, P.; Gaeta, F.S.; Mita, D.G.

doi:10.1016/s1381-1177(00)00240-x

Cited by 19 publications

(16 citation statements)

References 15 publications

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“…The immobilization of enzyme on natural or synthetic membranes has found interesting applications in biosensors or membrane bioreactors. One technique employed for the immobilization is grafting, by which inert supports become available for enzyme attachment [8].…”

Section: Introductionmentioning

confidence: 99%

Immobilization of urease using glycidyl methacrylate grafted nylon-6-membranes

Teke

Baysal

2007

Process Biochemistry

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Section: Introductionmentioning

confidence: 99%

Immobilization of urease using glycidyl methacrylate grafted nylon-6-membranes

Teke

Baysal

2007

Process Biochemistry

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“…8) interesting for its applications in biotechnological processes of industrial interest, particularly when low substrate concentrations are employed. When the results obtained under nonisothermal conditions with the packed-bed bioreactor are compared with those obtained under the same conditions with the planar membrane bioreactor (Diano et al, 2000;El-Masry et al, 2000aEl-Sherif et al, 2001 one concludes that the packed-bed bioreactor presents the advantage of higher reaction rates owing to the higher amount of immobilized enzymes, but the disadvantage of lower P.A.I. value.…”

Section: Discussionmentioning

confidence: 93%

“…Also the P.A.I. dependence on substrate concentration has been explained in terms of the effect of the process of thermodialysis on the rate of enzymatic reactions (Diano et al, 2000;El-Masry et al, 2001;El-Sherif et al, 2001).…”

Section: T Warmmentioning

confidence: 99%

“…Recently a new trick has been proposed (El-Masry et al, 2000a;El-Sherif et al, 2001;Febbraio et al, 1998;Mohy Eldin et al, 2000a;Schröen et al, 2001;Stellato et al, 1997;Travascio et al, 2002) to reduce the diffusional limitations. This new technology is based on the use of porous planar membranes, hydrophobic and catalytic, in a non-isothermal bioreactor.…”

Section: Introductionmentioning

confidence: 99%

“…The latter still remains effective under non-isothermal conditions. The influence of all these substrate fluxes in producing increases of enzyme activity has been demonstrated in the case of non-isothermal bioreactors employing planar catalytic membranes (Diano et al, 2000;El-Sherif et al, 2001, El-Masry et al, 2001. A quantitative analysis of the substrate profiles into the catalytic membrane, under isothermal and non-isothermal conditions as well as in the presence and in the absence of catalysis has been obtained by solving matter balance equations into the membrane volume (Diano et al, 2000).…”

mentioning

confidence: 99%

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A novel packed‐bed bioreactor operating under isothermal and non‐isothermal conditions

Maio

El-Masry

Martino

et al. 2004

Biotech & Bioengineering

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A novel packed-bed bioreactor, operating under isothermal and non-isothermal conditions, has been constructed. The core of the apparatus consisted in a polypropylene ring filled with beta-galactosidase immobilized on beads of polyacrylic acid, grafted with dimethylaminoethyl methacrylate. Phenylendiamine and glutaraldehyde were used as spacer and coupling agent, respectively. Two lateral nylon membranes held the enzyme beads into the ring and allowed the occurrence of the process of thermodialysis when the bioreactor was operating under non-isothermal conditions. Comparison of the enzyme activity under isothermal and non-isothermal conditions has shown that in the presence of temperature gradients the rate of lactose hydrolysis was increased, with a reduction of the apparent Km value. Under non-isothermal conditions the percentage increases of enzyme activity were found to decrease with the increase of the substrate concentration. The results have been explained within the frame of reference of the process of thermodialysis.

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Advantages of using non‐isothermal bioreactors for the enzymatic synthesis of antibiotics: The penicillin G acylase as enzyme model

Travascio

Zito

Maio

et al. 2002

Biotech & Bioengineering

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A new hydrophobic and catalytic membrane was prepared by immobilizing Penicillin G acylase (PGA, EC.3.5.1.11) from E. coli on a nylon membrane, chemically grafted with butylmethacrylate (BMA). Hexamethylenediamine (HMDA) and glutaraldehyde (Glu) were used as a spacer and coupling agent, respectively. PGA was used for the enzymatic synthesis of cephalexin, using D(-)-phenylglycine methyl ester (PGME) and 7-amino-3-deacetoxycephalosporanic acid (7-ADCA) as substrates. Several factors affecting this reaction, such as pH, temperature, and concentrations of substrates were investigated. The results indicated good enzyme-binding efficiency of the pre-treated membrane, and an increased stability of the immobilized PGA towards pH and temperature. Calculation of the activation energies showed that cephalexin production by the immobilized biocatalyst was limited by diffusion, resulting in a decrease of enzyme activity and substrate affinity. Temperature gradients were employed as a way to reduce the effects of diffusion limitation. Cephalexin was found to linearly increase with the applied temperature gradient. A temperature difference of about 3 degrees C across the catalytic membrane resulted into a cephalexin synthesis increase of 100% with a 50% reduction of the production times. The advantage of using non-isothermal bioreactors in biotechnological processes, including pharmaceutical applications, is also discussed.

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Urease immobilization on chemically grafted nylon membranes

Cited by 19 publications

References 15 publications

Immobilization of urease using glycidyl methacrylate grafted nylon-6-membranes

Immobilization of urease using glycidyl methacrylate grafted nylon-6-membranes

A novel packed‐bed bioreactor operating under isothermal and non‐isothermal conditions

Advantages of using non‐isothermal bioreactors for the enzymatic synthesis of antibiotics: The penicillin G acylase as enzyme model

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