NO138450B - PROCESS FOR THE PREPARATION OF CELLULOSE-BASED FIBERS WHICH ENCLOSE ENZYMES - Google Patents

Description

The present invention relates to a method for producing enzyme-containing cellulose fibers with high permeability.

It is known that a large number of reactions which would otherwise not be able to be carried out or would require more drastic operating conditions, could easily be carried out when they are catalysed by enzymes.

It is also known that enzyme-containing products can be used. fibers that exert their catalytic activity without being dispersed in the reaction mass. The incorporation of the enzymes is carried out by using fibers formed from a synthetic or semi-synthetic polymer material.

Enzyme-containing fibers can be produced by starting from polymer-free

suitable for the formation of fibres, in which the enzymatic substances are dispersed in the form of very small droplets of the same size as in emulsions. The emulsions thus obtained can be wet- or dry-spun for the production of fibres. whose insides show very small cavities containing the enzymes so that they are separated from the surrounding tissue by a very thin membrane. The hitherto used enzyme-containing fibres, the production of which is the subject of, for example, Norwegian Patent Document 129,351, have been obtained... by starting from polymers suitable for giving fibres, such as - example cellulose derivatives, but it is not known that they can be produced by simply starting from non-regenerated cellulose,'' . because of the difficulties that arise when the regeneration is to take place at the same time as the spinning process.

The use of enzyme-containing cellulose fibers has the advantage in relation. to other varieties/fibres that they have eh -higher activity, when it -, applies to enzymatic reactions due to the fibres' increased permeability. ! in reality, the catalytic effect of the enzymes is affected. in the fibers ■ of a".f ordeligs.pros.ess , why-the enzymatic activity depends on the permeability.-

Enzyme-containing fibers with high permeability are not always achieved

by simply influencing the fiber manufacturing conditions,

due to the fact that even at high enzyme concentrations permeability is still a limiting factor.

It has now been found that it is possible to produce enzyme-containing cellulose fibers by starting from cellulose polymers containing specified substituents and which are emulsified in a suitable manner with enzyme-containing solutions, then spun and finally the fibers thus obtained are subjected to reactions whereby the aforementioned substituents are removed. Thereby, enzyme-containing non-substituted cellulose fibers are obtained which have a much higher permeability than fibers produced from substituted cellulose.

The method according to the invention is essentially based on a chemical modification of the fiber starting material, including the effect of reducing agents and such operating conditions that they do not damage the enzymes. The present invention thus relates to a method for the production of cellulose-based fibers which ..enclose or enclose enzymes, where nitrocellulose is dissolved in a solvent that is insoluble in water, combined with an aqueous enzyme-containing solution and the emulsion obtained is subjected to spinning into fibers, and the peculiarity of the method according to the invention is that the nitro-cellulose fibers obtained during cleavage of the nitro-substituent are regenerated into enzyme-containing cellulose fibers by treatment with a reducing agent under working conditions that do not destroy or damage the enzymes.

With the method according to the invention, the above-mentioned disadvantages are overcome and the obtained enzyme-containing fibers after the reduction process have a high degree of permeability.

The starting material used essentially consists of high-molecular nitrocellulose with such a nitrogen content that the material is essentially soluble in organic solvents.

Preferably, the nitrogen content is higher than 5%.

The nitrocellulose is dissolved in a solvent which is not miscible with water, selected from n-butyl acetate, bis-butyl phthalate, methyl amyl ketone, ethyl amyl ketone and others which can be used as such or suitably diluted with aliphatic hydrocarbons such as pentane, hexane, heptane, octane, aromatic hydrocarbons such as toluene or, xylene, or hydrocarbon mixtures such as ligroin..

To the cellulose solution is added an aqueous solution containing enzymes that can be selected from a wide class. For example, use can be made of urease, invertase, lactase, acylase, glucose oxidase, catalase, papain, penicillin acylase and certain others. The emulsion is then spun according to known techniques by using known coagulants such as, for example, those specified in the above-mentioned patent document.

31ii',e obtained fibers are reacted with a reducing agent which removes the nitro groups and forms the enzyme-containing fibers according to the invention.

Ammonium sulphide solution with or without an excess of ammonia or ■hydrogen sulphide is advantageously used as a reducing agent. '

The following examples illustrate the invention.

Example 1 1,000 g of nitrocellulose (from Snia Viscosa S.p.A.) was dissolved in a solvent consisting of 6,900 g of n-butyl acetate and 4,600 g of toluene. An aqueous solution containing the enzyme invertase was then added.

Under stirring, an emulsion was obtained which was spun through nozzles with a diameter of 125 µm using a coagulant consisting of a mixture of saturated hydrocarbons

with boiling points varying from 40 to 70°C. It was achieved: approx. 2,600 g of enzyme-containing fibres.

1,000 g of these fibers immersed in a 20% sucrose solution at pH 4.5 inverted 40 g of sugar per minute.

1,000 g of fibers were treated with a 2% ammonia solution which had been saturated with hydrogen sulphide up to pH 8.5. After 6 hours of treatment, these treated fibers were washed and, by immersion in a 20% sucrose solution at pH 4.5, these latter fibers inverted 490 g of sugar per minute.

Example 2

1,000 g of nitrocellulose (from Snia Viscosa S.p.A.) was dissolved at room temperature in a mixture consisting of 7,000 g of n-butyl acetate and 3,750 g of toluene. 2,000 g of enzyme invertase solution was added to this solution. During stirring, an emulsion was obtained which

o o u ■ at 1 C was spun through nozzles with a diameter of 125 / and coagulated at 20°C in a mixture of saturated hydrocarbons with boiling points between 60 and 80°C. It was achieved approx. 3000 g of fibres.

1,000 g of the thus obtained fibers immersed in a 20% sucrose solution at pH 4.5, inverted 505 g of sugar per minute.

Another portion of 1,000 g of fibers was treated for 6 hours with an ammonia solution saturated with hydrogen sulphide as in example 1. After the treatment, the resulting fibers were immersed in a corresponding sucrose solution as in the previous example and 1,890. g of sugar was inverted per minute.

Example 3 1,000 g of nitrocellulose (from Snia Viscosa S.p.A.) was dissolved in a mixed composition. of 7,000 g of n-butyl acetate and 3,750 g of toluene. Then 2,000 g of an aqueous solution of the enzyme penicillin acylase was added and the whole was stirred into an emulsion.

The emulsion was spun as in example 1 and 3,000 g of fibers were obtained. 1,500 g of fibers were immersed in 37.5 liters of en-10; molar potassium phosphate solution at pH 8.0 containing 1,500 g potassium penicillin G at 37°C. The enzymes in the fibers catalyzed the hydrolysis of penicillin to 6-aminopenicillanic acid and phenyl acetic acid. During the reaction, the pH was kept constant by the addition of sodium hydroxide. In this way, 90% conversion of penicillin was achieved after 227 minutes..

2.000 g aqueous solution of the enzyme penicillin acylase. was "incorporated into 1,000 g of nitrocellulose as described above, and then dissolved in the ammonia solution saturated with hydrogen sulphide according to

example 1.

A corresponding solution of penicillin acylase was dispersed in a solution formed by dissolving 1,000 g of cellulose triacetate in 13,300 g of methylene chloride. This emulsion was spun as in example 1, the coagulant being toluene. -1 1,000 g of the first fibers were immersed in 25 liters of a 10 molar potassium phosphate solution of 37°C and pH 8.0 containing 10% potassium penicillin q . 90% of the penicillin was hydrolysed during the course

of 219 minutes.

Under the same conditions, the other fibers hydrolyzed 90% of penicillin within 298 minutes.

A further 1,500 g of fibers were treated with the ammonia solution. saturated with hydrogen sulphide according to Example 1. These fibers converted 90% penicillin in 56 minutes under the same conditions as for untreated fibres.

Claims (4)

1. Process for the production of cellulose-based fibers that enclose or contain enzymes, where nitrocellulose is dissolved in a solvent that is insoluble in water, combined with an aqueous enzyme-containing solution and the obtained emulsion is subjected to spinning into fibers, characterized in that the nitro-cellulose fibers obtained during cleavage of the nitro-substituent are regenerated into enzyme-containing cellulose fibers by treatment with a reducing agent under working conditions which do not destroy or damage the enzymes. 2. Method "as specified in claim 1, characterized in that an ammonium sulphide solution or an ammonium hydrogen sulphide solution as such or with a small excess of ammonia or hydrogen sulphide is used as the reducing agent." 3. Method as stated in claim 1, characterized in that the nitrocellulose is dissolved in n-butyl acetate, bis-butyl phthalate, methyl amyl ketone or ethyl amyl ketone. 4. Method as stated in claims 1-3, characterized in that the nitrocellulose is dissolved in a solvent which is insoluble in water and to which aliphatic hydrocarbons, aromatic hydrocarbons or mixtures of hydrocarbons have been added as a diluent.