A new immobilization technique of whole cells and enzymes with colloidal silica and alginate

Abstract

A mixed gel composed of colloidal silica and alginate (As gel) was prepared for the immobilization of enzymes or microorganisms. The physical strength of AS gel increased with the amount of colloidal silica. The ethanol production rate of Saccharomyces cerevisiae (IFO 0224) immobilized in AS gel was higher than in alginate gel (Al gel) in the early phase of growth. At a concentration of glucose of more than 10%, the ethanol production of immobilized yeast in AS gel was higher than in Al gel. Any difference was not recognized in the diffusion coefficient of glucose between AS and Al gels. The AS gel had an ability to retain proteins such as bovine serum albumin and gamma-globulin. The alkaline protease and beta-galactosidase in AS gel continued their function for a long time, but those immobilized in Al gel did not. Immobilized beta-galactosidase in AS gel had a higher thermal stability than in Al gel or free enzymes.

Rheological behavior of thermoreversible κ-carrageenan/nanosilica gels

“…The interest in the use of biopolymers combined with nanosized silica to produce materials for biotechnological processes has long been recognized [1,2]. For example, biopolymer/silica nanocomposites are of interest for advanced biomedical materials such as tissue engineering, cell encapsulation and in the production of biosensors and bioreactors [3].…”

“…Also, following the sequence of recent studies of the role of biomolecules on silica polymerization taking place in several micro-organisms, biomimetic approaches to silica based hybrid materials have been carried out [4,5]. A wide variety of biopolymers, including gelatin, alginates, cellulose derivatives [1][2][3][6][7][8] and carrageenans [9,10] have been employed to produce biopolymer/silica nanocomposites. Carrageenans are water soluble and obtained from several species of marine red algae.…”

Immobilization of Photosynthetic Microorganisms for Efficient Hydrogen Production

“…To avoid cells drying during xerogel formation, several methods were applied. Fukushima et al (1988) entrapped whole cells in alginate-silica gels with very promising results. Other authors employed biocompatible short chain phospholipids to direct the formation of an ordered silica mesophase during evaporative processes (Baca et al 2007).…”

Inhibitory effect of propolis extract on the growth of Listeria monocytogenes and the mutagenicity of 4‐nitroquinoline‐N‐oxide

“…For electron microscopy, samples were prepared according to the method described by Fukushima et al 21 Samples of the cell-containing pellets were fixed in 2.5% glutaraldehyde in 0.1 mol L −1 Tris buffer (pH 7.3) at 4 • C for 1 h. After being washed twice in a Tris buffer with 5% sucrose, they were post-fixed in 1.0% osmium tetroxide solution in the same buffer for 1 h. The resultant osmium-treated cells were then washed with 0.1 mol L −1 Tris buffer and dehydrated by successive extraction with 50%, 70%, 80%, 90% and 95% ethanol, each for a period of 10 min, and finally with 100% ethanol for 15 min, twice. They were then dried using the CO 2 critical-point drying technique, coated with gold and examined with a scanning electron microscope (Model JSM-6300, JEOL, Tokyo, Japan).…”