Immobilization of microorganisms in a hydrophilic complex gel

Claim 2

A process for producing a hydrophilic complex xerogel in which microbial cells are immobilized, which comprises mixing an aqueous solution of a water-soluble-polymer compound selected from the group consisting of polyvinylalcohol, gelatin and carboxymethylcellulose with a tetraalkoxysilane of the general formula: Si(OR) 4 , wherein R represents an alkyl group of up to 12 carbon atoms, hydrolyzing the resulting mixture by addition of an acid or acidic compound to form a transparent homogeneous complex sol, and dispersing the microbial cells in said sol homogeneously, at a pH between 4 and 8 and subsequently gelling the mixture of said sol and said microbial cells by drying, the amount of said tetraalkoxysilane, calculated based on SiO 2 formed by acid hydrolysis, being 5 to 300% by weight of the dry weight of said water-soluble-polymer.

Claim 3

The process according to claim 1, wherein R of said tetraalkoxysilane is an alkyl group of up to 3 carbon atoms.

Claim 4

The process according to claim 1, wherein said water-soluble-polymer compound is polyvinyl-alcohol and said tetraalkoxysilane is tetraethoxysilane.

Claim 5

The process according to claim 1, wherein the weight of SiO 2 contained in said tetraalkoxysilane is at least 20% of the dry weight of said water-soluble-polymer compound.

Claim 6

The process according to claim 1, wherein the size of said microbial cell is within about 0.5 to 1.5μ in width, and within about 1 to 20μ in length.

Claim 7

The process according to claim 1, wherein the mixture of said homogeneous complex sol and said microbial cells is dried at a temperature between 0° and 70° C.

Claim 8

The process according to claim 1, wherein the dry weight of said microbial cells is 20 to 1,000% of that of said homogeneous complex sol.

Claim 9

A process for producing a hydrophilic complex xerogel in which microbial cells are immobilized which comprises mixing an aqueous solution of a water-soluble-polymer compound selected from the group consisting of polyvinylalcohol, gelatin and carboxymethylcellulose with a tetraalkoxysilane of the general formula: Si(OR) 4 , wherein R represents an alkyl group of up to 12 carbon atoms, and hydrolyzing the resulting mixture by addition of an acid or acidic compound to form a transparent homogeneous complex sol, and dispersing the microbial cells in said sol homogeneously at a pH between 4 and 8, and gelling the mixture of said sol and said microbial cells by casting into organic solvent and drying, the amount of said tetraalkoxysilane, calculated based on SiO 2 formed by acid hydrolysis, being 5 to 300% by weight of the dry weight of said water-soluble-polymer.

Claim 10

A process for producing a hydrophilic complex xerogel in which microbial cells are immobilized which comprises mixing an aqueous solution of a water-soluble-polymer compound selected from the group consisting of polyvinylalcohol, gelatin and carboxymethylcellulose with a tetraalkoxysilane of the general formula: Si(OR) 4 , wherein R represents an alkyl group of up to 12 carbon atoms, and hydrolyzing the resulting mixture by addition of an acid or acidic compound to form a transparent homogeneous complex sol, and dispersing the microbial cells in said sol homogeneously at a pH between 4 and 8, and gelling the mixture of said sol and said microbial cells by casting into organic solvent and drying, the amount of said tetraalkoxysilane, calculated based on SiO 2 formed by acid hydrolysis, being 5 to 300% by weight of the dry weight of said water-soluble-polymer.

Claim 11

The process according to claim 8, wherein R of said tetraalkoxysilane is an alkyl group of up to 3 carbon atoms.

Claim 12

The process according to claim 8, wherein said water-soluble-polymer compound is polyvinyl-alcohol and said tetraalkoxysilane is tetraethoxysilane.

Claim 13

The process according to claim 8, wherein the weight of SiO 2 contained in said tetraalkoxysilane is at least 20% of the dry weight of said water-soluble-polymer compound.

Claim 14

The process according to claim 8, wherein the size of microbial cell is within about 0.5 to 1.5μ in width, and within about 1 to 20μ in length.

Claim 15

The process according to claim 8, wherein the mixture of said homogeneous complex sol and said microbial cells is dried at a temperature between 0° C. and 70° C.

Claim 16

The process according to claim 8, wherein the dry weight of said microbial cells is 20 to 1,000% of that of said homogeneous complex sol.