JPH0457319B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a reaction carrier for a bioreactor. More specifically, the present invention relates to a reaction carrier for a bioreactor that can provide an immobilized enzyme or an immobilized bacterial cell with excellent activity and a fast reaction rate.

Conventional technology In recent years, with the progress of biotechnology, methods for continuously producing useful substances using bioreactors containing immobilized enzymes and immobilized bacterial cells as elements have begun to be applied, and improvements in quality, cost, and energy saving have begun to be applied. Its advantages are attracting attention in such aspects.

Methods for immobilizing enzymes and bacterial cells are broadly classified into entrapment methods, crosslinking methods, and carrier binding methods, and carrier binding methods can be further subdivided into covalent bonding methods, ionic bonding methods, and physical adsorption methods. The immobilized enzymes and immobilized bacterial cells obtained by these methods are usually in the form of a gel or film, and are used by being filled into a reaction vessel such as a column. However, these solidified enzymes and immobilized microbial cells have the disadvantage that the amount of enzyme or microbial cells per unit weight of the carrier is small, the surface area is small, and the reaction rate is slow.

Therefore, in order to improve these drawbacks, the present inventors first developed an enzyme-immobilized fiber (Japanese Patent Publication No. 57-17083
(Japanese Patent Application Laid-Open No. 1989-198976) and bacterial cell-immobilized fiber
Publication No.) was found. These enzyme-immobilized fibers and bacterial cell-immobilized fibers are currently being considered for industrial application in the production of invert sugar using glucose isomerase, the saccharification of starch using glucoamylase, and the like.

However, with these enzyme-immobilized fibers and bacterial cell-immobilized fibers, in reactions involving gas such as aerobic fermentation, the diffusion of gas into the immobilization carrier and fiber bundle is slow, and the enzymes and bacterial cells are It has the disadvantage that the activity cannot be fully utilized, and this tendency is particularly strong when using immobilized fibers.

Problems to be Solved by the Invention The purpose of the present invention is to improve the drawbacks of conventional immobilized enzymes and immobilized microbial cells, to provide excellent activity and fast reaction rate, and to improve aerobic fermentation. It is an object of the present invention to provide a carrier for providing immobilized enzymes and immobilized microbial cells that can fully utilize the activities of enzymes and microbial cells even in reactions involving gases such as the above.

Means for Solving the Problems The present inventors have conducted intensive research to develop carriers capable of providing immobilized enzymes and immobilized bacterial cells having the above-mentioned excellent characteristics. The inventors have discovered that the objective can be achieved by coating the outer surface of a fluid-permeable hollow fiber that is permeable to an enzyme or a fiber for fixing bacterial cells, and based on this knowledge, the present invention has been completed.

That is, the present invention provides a reaction carrier for a bioreactor, which comprises a fluid-permeable hollow fiber whose outer surface is coated with fibers for immobilizing enzymes or bacterial cells.

Examples of fibers for immobilizing enzymes or bacterial cells, which are one of the constituent materials of the reaction carrier of the present invention, include aminoacetalized polyvinyl alcohol ultrafine fibers, sulfonated polyvinyl alcohol fibers, vinylpyridine-grafted polyolefin fibers, and vinylpyridine-grafted polyolefin fibers. Examples include cationized or anionized synthetic fibers such as polyester fibers.

These fibers are preferably ultrafine fibers with a diameter in the range of 0.05 to 1 μm.

The above-mentioned fibers for immobilizing enzymes and bacteria have a larger surface area than other fibers, and can immobilize a large amount of enzymes and bacteria per unit volume, and can be processed into various forms by knitting or weaving. It has characteristics such as being able to

Fluid-permeable hollow fibers, which are another constituent material, include porous hollow fibers made of cellulose acetate, polyolefin, polyester, polysulfone, polyethersulfone, etc., which are widely used as filtration membranes, ceramic porous hollow fibers, etc. Examples include hollow fibers having an oxygen enrichment function such as polysiloxane.

Among these hollow fibers, those having an oxygen enrichment function are particularly suitable for immobilizing bacterial cells.

The reaction carrier of the present invention is one in which the outer surface of these hollow fibers is coated with the above-mentioned fibers for immobilizing enzymes or microbial cells.As a method of coating, for example, (1) centering on the hollow fibers and surrounding them; Methods used include weaving the fixing fibers into a braided cord, (2) wrapping the fixing fibers around hollow fibers, and (3) co-weaving the hollow fibers and the fixing fibers.

As a bioreactor material that combines hollow fibers that has been reported so far, an aerobic two-layer hollow fiber type bioreactor material that combines silicone hollow fibers and polypropylene porous hollow fibers has been reported. [“Biotechnology and Bioengineering (Biotechnol.
Bioeng.), Volume 12, Page 1012 (1985)]. In this material, three silicone hollow fibers with an outer diameter of 0.2 mm and an inner diameter are placed inside a polypropylene porous hollow fiber with an outer diameter of 1.5 mm and an inner diameter of 1.2 mm.
The seeds are grown and immobilized in the interstices of the hollow fibers.

The oxygen involved in the reaction is supplied from inside the silicon hollow fiber, and the substrate is supplied from the outside of the polypropylene hollow fiber.

However, in this material, the substrate and product are transferred through the polypropylene hollow fiber membrane, resulting in high diffusion resistance, and furthermore, it is difficult to industrially produce long double-layered hollow fibers. The problem is that it is extremely difficult.

On the other hand, in the reaction carrier of the present invention,
When the reaction substrate is a single component, by feeding the substrate from the inside of the hollow fiber, the separation function of the hollow fiber membrane allows the substrate to be concentrated in the fibers located just outside the hollow fiber. The immobilized enzyme is supplied to the immobilized enzyme or the immobilized bacterial cells, which is quickly converted into a reaction product and discharged from the system.On the other hand, in the case of two components, one of the components is extracted from the inside of the hollow fiber, and the remaining By supplying the component directly to the fibrous immobilized enzyme or the immobilized bacterial cells, it is converted into a reaction product.

Effects of the Invention The immobilized enzyme or immobilized bacterial cells using the reaction carrier for bioreactor of the present invention has a
It has excellent activity and good contact with the substrate, resulting in a fast reaction rate, and there are fewer problems with channel flow, and the reaction products are discharged outside the enzyme and bacterial system, making it difficult for reverse reactions to occur. It has excellent features such as being able to carry out reactions with high efficiency, and even in reactions involving gases such as aerobic fermentation, the activities of enzymes and microbial cells can be fully utilized.

In addition, the reaction carrier of the present invention is thread-like or string-like, and can be processed into various forms by knitting, weaving, or bundling, and is a very effective material for designing the shape of the reactor. and
Moreover, it has the advantage that it can be manufactured by a method commonly used in the textile industry.

The reaction carrier of the present invention is used for bioreactors such as aerobic fermentation, aerobic wastewater treatment, nitrification and denitrification treatment of wastewater, and biological treatment of exhaust gas, and a general catalyst is immobilized on the carrier. Therefore, it can also be used as a non-biological reactor material.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples.

Example 1 A yarn consisting of 10,000 single fibers of aminoacetalized polyvinyl alcohol fibrillated fibers with an outer diameter of 0.6
A reaction carrier was prepared by knitting the outside of silicone hollow fibers with a diameter of 0.3 mm and an inner diameter of 0.3 mm into a braided cord. The fiber weight per meter of carrier is 0.1 g.

This reaction carrier was bundled, both ends were embedded in silicone sealant, and after solidification, the ends were cut to create a module for a reactor. This module consists of 500 50cm reaction carriers.
When air is supplied to the silicon hollow fiber at a pressure of 1.5 kg/ ^cm2 at 20°C, the oxygen transfer to water is 10.5 ppm as an equilibrium dissolved oxygen concentration, which is higher than the normal dispersion value of 8.84 ppm. , which had an oxygen enrichment function.

The module contains 0.65g of peptone and glucose.
Approximately 7.5 microorganisms for aerobic treatment were immobilized on the immobilizing fibers by acclimatizing them for three days with artificial sewage containing 0.65 g and 0.05 g of monopotassium phosphate, to which seed sludge was added.

Using this immobilized module of microorganisms,
When artificial sewage 1 containing 2000 ppm of BOD was treated using a silicone hollow fiber with air lengthened at a pressure of 1.5 kg/ ^cm2 , the treatment speed was three times that of the normal activated sludge method, and the sludge There was no need for separation.

Example 2 Using the same module as described in Example 1, 1
As an inoculum in a medium containing 25 g of glucose, 8 g of ethanol, 1 g of yeast extract, 0.3 g of peptone, 0.3 g of ammonium hydrogen phosphate, 0.1 g of potassium monohydrogen phosphate, and 0.005 g of magnesium sulfate.
When Acetobacter aceti was added and acclimatized, approximately 10 g of bacterial cells were immobilized on the entire module.

1.5 to the immobilized module of this acetic acid bacterium
Adjust the concentration of ethanol while supplying Kg/ ^cm2 of air.
When cultured at 30°C in the above-mentioned medium increased to 20 g, the production amount of acetic acid was 1.5 g/hr, which was 1.5 times more efficient than the batch method.

Claims (1)

[Scope of Claims] 1. A reaction carrier for a bioreactor comprising a fluid-permeable hollow fiber coated with fibers for immobilizing enzymes or bacterial cells. 2. The reaction carrier for a bioreactor according to claim 1, wherein the fluid-permeable hollow fibers have an oxygen enrichment function. 3. The reaction carrier for a bioreactor according to claim 1, wherein the fixing fiber has a diameter of 0.05 to 1 μm.