CN1796552A - Method for preparing porous material in lumpy in use for biological zymophore - Google Patents

Abstract

The invention provides a method for preparing block-shaped porous materials used for biological enzyme carriers, using metal alkoxides and organic polymers as main raw materials, and preparing SiO ₂ and SiO ₂ -TiO ₂ blocks by using a sol-gel method Porous materials as bioimmobilized enzyme carriers. The immobilized enzyme carrier prepared by the invention has a diameter of 10-50mm, a height of 2-10mm, and a density of 0.3-1.2g/cm ³ , which is suitable for reactor operation; the preparation method has high yield and short preparation cycle, and is suitable for batch production Chemical production; the product has good chemical stability and narrow pore size distribution.

Description

A kind of preparation method of bulk porous material used for biological enzyme carrier

technical field

The invention relates to a method for preparing SiO ₂ and SiO ₂ -TiO ₂ bulk porous materials as bioimmobilized enzyme carriers by using metal alkoxide and organic polymer as main raw materials and using a sol-gel method.

Background technique

Enzymes are proteins synthesized by living organisms, which have been used as catalysts for almost all chemical reactions in living organisms. In the past, the enzyme reaction can only be carried out in aqueous solution, and the enzyme and the substrate are mixed in batches one at a time. After the reaction is completed, the enzyme is separated from the product, but it is very difficult to keep its activity from loss during recovery. difficult. In fact, during each separation reaction, a portion of the enzyme is wasted. Making the enzyme water-insoluble and immobilized enzyme can change the enzyme reaction into a continuous process, and the enzyme can be used repeatedly and realize the continuous automation of the reaction process, and the process can also be precisely controlled. In the early 1960s, katchallski-Katzir and others first immobilized some proteolytic enzymes on insoluble carriers or wrapped them in artificial membranes to make immobilized enzymes, such as literature 1: Annu.Rev.Biochem.35, 773- 908, 1966. In 1967, Chibata et al. of Tanake Seiyaku Company in Japan successfully used immobilized enzyme technology for industrial production for the first time, as described in Document 2: Biotechnol.Bioeng.9, 603-615, 1967. The use of immobilized enzymes for industrial production not only enables enzymes to be recycled and reused, reduces catalyst costs, but also improves enzyme stability, avoids contamination of products by enzyme proteins, and simplifies post-processing. Research in this area is developing rapidly . Preparation of effective porous supports has always been a research focus in this field.

Currently widely used porous carriers for immobilizing enzymes include cellulose, other polymer substances and porous glass. Organic porous materials with poor chemical stability are not ideal enzyme carriers. Compared with organic porous materials, inorganic porous materials have the following advantages: ① high thermal stability, the use temperature can generally reach above 400 ℃; ② good chemical stability, acid and alkali resistance; ③ high compressive strength, suitable for high pressure conditions; ④The composition of inorganic substances is generally non-toxic, will not cause secondary pollution, and is easy to clean and regenerate; ⑤Generally, it does not have biochemical reactions with microorganisms, and is resistant to microbial degradation and dissolution by organic solvents; ⑥The fatigue aging of materials is extremely Slow, long service life; ⑦ narrow hole distribution. If the bioreactor operates at a higher temperature for a long time for several months, this provides the possibility for bacterial proliferation. However, in the stable micropores of inorganic substances, bacteria larger than 100 nm cannot enter, so the pore size can be kept stable, while organic porous bodies will be eroded by bacteria.

Porous silica glass can be produced by melting and re-phase separation, such as Document 3: Journal of Silicates, 1984, 12(2), 193-202. However, the phase separation method needs to melt the glass at a high temperature of 1500°C, reheat at 500°C to 600°C, and then undergo a long-term acid treatment. The manufacturing process is complicated and difficult to control, and the product is expensive. In addition, this method requires acid treatment with HF or concentrated sulfuric acid to form holes, which will pollute the environment; the yield is low.

It is a traditional method to introduce a pore-forming agent into the ceramic ingredients and volatilize the pore-forming agent through firing to make porous ceramics. There are two types of pore-forming agents: inorganic and organic. Inorganic pore-forming agents include: ammonium carbonate, ammonium bicarbonate, ammonium chloride, coal powder, carbon powder, etc.; organic pore-forming agents mainly include: natural fibers, high molecular polymers, organic Acid, etc., the forming method of porous ceramics is the same as that of ordinary ceramics. This process can produce ceramic products with complex shapes and various pore structures, but the disadvantages are poor pore distribution, low porosity and large pore diameter, such as Document 4: Powder Metallurgy Technology, 2002, 20(6), 365-368.

The sol-gel synthesis of ordered porous materials is a new method developed in recent years. The basic process of this method is: dissolving metal alkoxide in lower alcohol, slowly dripping water to carry out hydrolysis reaction to obtain the sol of the corresponding metal oxide, adjusting the pH value of the sol, and the nanoscale metal oxide particles will be Aggregation occurs, forming a gel. The gel is dried and heat-treated to obtain metal oxide materials (usually ceramics). Due to the decomposition of organic substances or the dissolution of inorganic substances during the preparation process, the pore sizes of products at different stages are different. The combination of sol-gel method and other methods is a method for preparing porous materials with high regularity and submicron scale, such as literature 5: Journal of Inorganic Materials, 2002, 17(3), 407-414. According to the recent reports of "SCIENCE" and "NATURE", the latest methods for the preparation of porous materials mainly include: ①Using uniform radius particles as templates combined with sol-gel method, ②Using surfactants as templates combined with sol -Gel method, ③Using a compound with a special structure as a template combined with a sol-gel method, such as Document 6: New Chemical Materials, 2001, 29(1), 22-25. There are mostly reports on the preparation of porous membranes and powder materials by these methods, but there are few studies on the synthesis of bulk porous materials suitable as enzyme carriers. Moreover, porous powders such as MSM-41 will collapse if they are used in a hot solution system for a long time, and the pore size is less than 10nm, which is not suitable for such commercial applications.

Contents of the invention

In order to overcome the shortcomings of the above-mentioned immobilized enzyme carrier, the present invention provides a method for preparing a bulk porous material for a biological enzyme carrier, to solve the problem that the porous block is difficult to synthesize, improve the chemical stability of the carrier, and improve enzyme activity.

The purpose of the present invention is achieved like this:

The method for preparing the bulk porous material used for biological enzyme carrier provided by the invention comprises the following steps:

(1) Synthesis of sol and gel:

The proportion of ingredients is as follows:

A: 0-80 parts by weight of tetraethyl orthosilicate;

B: 0-50 parts by weight of n-butyl titanate;

C: 0.5-50 parts by weight of organic polymer;

D chemical additive 0.5-20 parts by weight

E: 0.5-20 parts by weight of chemical drying control agent;

F: 0.1-10 parts by weight of catalyst;

The number of components A and B cannot be 0 at the same time; the organic polymer is one or more of polyethylene glycol, polyvinyl alcohol, polyacrylamide, polyacrylic acid, polymethacrylic acid, and polyethylene oxide; The chemical additive is γ-aminopropyltriethoxysilane; the chemical drying control agent is one or more of acetylacetone, N,N-dimethylformamide and dimethylformamide; the catalyst is acetic acid, hydrochloric acid One or more of , nitric acid and ammonia water;

Fully mix A, B, C, D, E, F, carry out hydrolysis and polycondensation in a system containing water and ethanol, the reaction temperature is 20-80°C, polymerize for 30 minutes-5 hours, and then solidify for 0.5-10 hour, a wet gel was obtained.

(2) Blocking and heat treatment:

The wet gel is dried in a vacuum oven at 50-250°C, then the dry gel is crushed in an agate mortar, ground, passed through a 40-500 mesh sieve, and then pressed into a mold with a molding pressure of 5- 50MPa. After drying, the formed block is heated to 400-1000° C. for 1-5 hours, and then the organic matter is removed to obtain a white light porous block.

Beneficial effects: the immobilized enzyme carrier prepared by the invention has a diameter of 10-50mm, a height of 2-10mm, and a density of 0.3-1.2g/cm ³ , which is suitable for reactor operation; the preparation method has a high yield and a short preparation cycle. It is suitable for mass production; the product has good chemical stability and narrow pore size distribution.

The present invention will be described in detail below in conjunction with examples.

Example 1:

(1) Fully mix 50g of tetraethyl orthosilicate, 20g of n-butyl titanate, 30g of polyethylene glycol, 100ml of ethanol and 5ml of water at room temperature, then add 5ml of ammonia water, 10ml of acetylacetone, γ-aminopropyl triethyl Oxysilane 5ml, stirred and reacted. The temperature was raised to 80°C for 30 minutes for polymerization, and then cured for 7 hours at 50°C to obtain a xerogel.

(2) Dry the xerogel in a vacuum oven at 250° C., then sieve the powder, and then press the powder into a mold with a molding pressure of 5 MPa. The molded block was heated at a rate of 4°C/min to 800°C for 2 hours, and then the organic matter was removed to obtain a white light porous block.

Example 2:

The preparation process is the same as that in Example 1. Fully mix 50 g of tetraethyl orthosilicate, 20 g of n-butyl titanate, 30 g of polyvinyl alcohol, 100 ml of ethanol and 20 ml of water at room temperature, then add 5 ml of ammonia water, 10 ml of acetylacetone, and γ-aminopropyl 5 ml of triethoxysilane was stirred and reacted, and the temperature was raised to 20°C for polymerization for 5 hours, and cured at 50°C for 0.5 hour to obtain a xerogel.

(2) Dry the xerogel in a vacuum drying oven at 80° C., then sieve, and then press the powder into a mold with a molding pressure of 30 MPa. After the molded block is heated to 400° C. for 1 hour, the organic matter is removed, and a white light porous block is obtained.

Example 3:

The preparation process is the same as that in Example 1. Fully mix 50 g of tetraethyl orthosilicate, 20 g of n-butyl titanate, 30 g of polyacrylamide, 100 ml of ethanol and 15 ml of water at room temperature, then add 5 ml of ammonia water, 10 ml of acetylacetone, and γ-aminopropyl 5 ml of triethoxysilane was stirred and reacted, and the temperature was raised to 50°C for polymerization for 3 hours, and then cured for 10 hours at 50°C to obtain a xerogel.

(2) Dry the xerogel in a vacuum drying oven at 165° C., then sieve, and press the powder into a mold with a molding pressure of 25 MPa. The molded block was heated at a rate of 4°C/min to 700°C for 5 hours, and then the organic matter was removed to obtain a white light porous block.

Example 4:

The preparation process is the same as that in Example 1. Fully mix 50 g of tetraethyl orthosilicate, 30 g of polyacrylic acid, 100 ml of ethanol and 15 ml of water at room temperature, then add 5 ml of ammonia water, 10 ml of acetylacetone, and 5 ml of γ-aminopropyltriethoxysilane, Stirring, reaction, other unchanged.

Example 5:

The preparation process is the same as that in Example 2. Fully mix 40 g of n-butyl titanate, 30 g of polymethacrylic acid, 100 ml of ethanol and 15 ml of water at room temperature, then add 5 ml of ammonia water, 10 ml of acetylacetone, and γ-aminopropyltriethoxysilane 5ml, stirred and reacted, and the rest remained unchanged.

Embodiment 6:

The preparation process is the same as in Example 3. At room temperature, 50 g of tetraethyl orthosilicate, 20 g of n-butyl titanate, 30 g of polyethylene oxide, 100 ml of ethanol and 15 ml of water are fully mixed, and then 5 ml of ammonia water, 10 ml of acetylacetone, and γ-ammonia are added. 5ml of propyltriethoxysilane was stirred and reacted, and the others remained unchanged.

Embodiment 7:

The preparation process is the same as that in Example 1. Fully mix 50 g of tetraethyl orthosilicate, 20 g of n-butyl titanate, 30 g of polyethylene glycol, 100 ml of ethanol and 15 ml of water at room temperature, then add 5 ml of ammonia water, N, N-dimethyl 20ml of formamide and 5ml of γ-aminopropyltriethoxysilane were stirred and reacted, and the rest remained unchanged.

Embodiment 8:

The preparation process is the same as that in Example 1. Fully mix 50 g of tetraethyl orthosilicate, 20 g of n-butyl titanate, 30 g of polyethylene glycol, 100 ml of ethanol and 15 ml of water at room temperature, then add 5 ml of ammonia water, 25 ml of dimethylformamide, 5ml of γ-aminopropyltriethoxysilane was stirred and reacted, and the others remained unchanged.

Embodiment 9:

The preparation process is the same as that in Example 1. Fully mix 50 g of tetraethyl orthosilicate, 20 g of n-butyl titanate, 30 g of polyethylene glycol, 100 ml of ethanol and 15 ml of water at room temperature, then add 10 ml of acetic acid, 10 ml of acetylacetone, and γ-ammonia 5ml of propyltriethoxysilane was stirred and reacted, and the others remained unchanged.

Example 10:

The preparation process is the same as that in Example 1. Fully mix 50 g of tetraethyl orthosilicate, 20 g of n-butyl titanate, 30 g of polyethylene glycol, 100 ml of ethanol and 15 ml of water at room temperature, then add 6 ml of hydrochloric acid, 10 ml of acetylacetone, and γ-ammonia 5ml of propyltriethoxysilane was stirred and reacted, and the others remained unchanged.

Example 11:

The preparation process is the same as that in Example 1. Fully mix 50 g of tetraethyl orthosilicate, 20 g of n-butyl titanate, 30 g of polyethylene glycol, 100 ml of ethanol and 15 ml of water at room temperature, then add 8 ml of nitric acid, 10 ml of acetylacetone, and γ-ammonia 5ml of propyltriethoxysilane was stirred and reacted, and the others remained unchanged.

Example 12:

The preparation process is the same as that in Example 1. Fully mix 60 g of tetraethyl orthosilicate, 30 g of polyethylene glycol, 80 ml of ethanol and 15 ml of water at room temperature, then add 5 ml of ammonia water, 10 ml of acetylacetone, and γ-aminopropyltriethoxysilane 5ml, stirred and reacted, and the rest remained unchanged.

Example 13:

(1) The ingredients are the same as in Example 1. After the dry gel is obtained, it is dried in a vacuum oven at 50° C., and then sieved. Others remain unchanged.

Example 14:

(1) The ingredients are the same as in Example 1. After the dry gel is obtained, it is dried in a vacuum oven at 250° C., then sieved, and the powder is pressed into a mold with a molding pressure of 50 MPa. The molded block was heated at a rate of 4°C/min to 1000°C for 1 hour, and then the organic matter was removed to obtain a white light porous block.

Claims (4)

1, is used for the preparation method of the block porous material of biological enzyme carrier, it is characterized in that, comprise the following steps:

(1) colloidal sol, gel is synthetic:

Proportion scale is as follows:

A: tetraethoxy 0-80 weight part;

B: tetrabutyl titanate 0-50 weight part;

C: organic polymer 0.5-50 weight part;

D chemical additive 0.5-20 weight part

E: chemical seasoning control agent 0.5-20 weight part;

F: catalyzer 0.1-10 weight part;

Wherein the umber of composition A and B can not be 0 simultaneously; Organic polymer is one or more in polyoxyethylene glycol, polyvinyl alcohol, polyacrylamide, polyacrylic acid, polymethyl acrylic acid, the polyoxy ethane; Chemical additive is a γ-An Bingjisanyiyangjiguiwan; The chemical seasoning control agent is methyl ethyl diketone, N, one or more in dinethylformamide and the dimethyl formamide; Catalyzer is one or more in acetic acid, hydrochloric acid, nitric acid and the ammoniacal liquor;

A, B, C, D, E, F thorough mixing are carried out, be hydrolyzed in containing water and alcoholic acid system, polycondensation, temperature of reaction is 20-80 ℃, and polyase 13 0 minute-5 hours solidified 0.5-10 hour again, obtained wet gel;

(2) become piece and thermal treatment:

Wet gel is dried in 50-250 ℃ of following vacuum drying oven, then xerogel smashed, grind, crossed to pieces the 40-500 mesh sieve in agate mortar, compression moulding in mould again, forming pressure is 5-50MPa, by drying, the block of moulding is removed organism after being warming up to 400-1000 ℃ of following thermal treatment 1-5 hour again, promptly obtains white light-weight porous bulk.

2, require 1 described preparation method as getting profit, it is characterized in that the solidification value in the step (1) is 50 ℃.

3, require 1 described preparation method as getting profit, it is characterized in that, the heat treated temperature rise rate of formed blocks is 4 ℃/min in the step (2).

4, require 1 described preparation method as getting profit, it is characterized in that, xerogel is smashed, is ground the back to pieces and crosses the 60-300 mesh sieve in step (2).