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Biocatalysis(enzymes or microbes) is the key factor to change (usually accelerated) chemical reactions.uses.
Dec 10, 2017

Biocatalysis(enzymes or microbes) is the key factor to change (usually accelerated) chemical reactions.

 

Biocatalysts are the general names of free or immobilized cells, as well as free or immobilized enzymes, in the process of biological reaction.

 

Characteristics: 1. High efficiency. Two, highly specialized. Three. The conditions are mild. Four, clean and environmental protection.

 

Application of biocatalysts

At present, the biocatalytic process has had a great influence on the chemical industry, and the scale of the global enzyme market is about 6 billion dollars. Traditionally, microorganism and enzyme technology has been applied to the manufacture of bio derived raw materials. Now it has been extended to the field of petroleum derived materials, and has been widely applied in organic drug synthesis and diesel microbial desulfurization, and it has been used as disproportionation agent in the reaction. When producing chiral small molecule drugs and intermediates, the most notable difference between biotransformation and traditional chemical methods is the asymmetric synthesis of chiral compounds. As biocatalysts are a kind of protein - based catalyst, the catalytic activity of biocatalysts is easily affected by temperature and pH. With the increase of temperature, the reaction speed, but above a certain temperature (usually 45 to 50 DEG C), protein denaturation will, the reaction rate will be decreased rapidly; it is also only in a limited range of pH value reaction, so each enzyme has its optimum temperature and pH value. Some industrial processes need to be carried out under certain conditions such as temperature, pressure, pH value or organic solvent. Therefore, the biocatalyst should be highly tolerant to meet the needs of industrial production. At present, the application of biocatalysis technology is mainly limited to the non - suitable biocatalysts, and the ideal biocatalysts can be obtained by modern screening technology.

 

Screening of biocatalysts

The wide application of biocatalysts depends on the effective screening and testing of a large number of biomolecules. There are great differences in the specificity, vitality and stability of different strains and different enzymes. Therefore, the separation, screening and selection of strains are indispensable. In practice, to expand the application of biocatalysts, we must solve some typical difficulties and operational limitations in biocatalysis, such as temperature, pH value, product inhibition, reaction speed and material concentration. To solve these problems, it is necessary to keep the selectivity and specificity of the catalyst as a prerequisite. In the biocatalyst screening, the traditional methods have been broken. At present, the combination of biological mutation technology and high pass screening technology is an effective way to obtain ideal biocatalyst.

 

The source of biocatalysts

At present, a few biocatalysts are extracted from the plant tissues, most of which are derived from microbiological cells. Prokaryotic microbes are the main source of biocatalysts, except for eukaryotes and single cell yeast, such as high efficient lipase CALB from Candida Antarctica. The prokaryotic microorganisms (bacteria and archaea) on earth is the earliest and largest number of life forms, experienced a long evolution, many microorganisms to adapt to the environment and has a very high tolerance, which can get a large number of high performance bio catalyst from. Now, although microbial culture has its limitations, many organisms cannot be cultured with current technology, but biocatalysis is still the most common and effective way through microbial culture. This is because microbial culture can accelerate the metabolism of organisms and increase the number of them, providing a favorable condition for high throughput screening in the future.

(Elim bioscience solves the worry of your enzyme application)

Shortcomings of biocatalysts

The catalyst is the essence of biological enzyme, although has the advantages of high catalytic efficiency, high specificity and less pollution, but in organic solvent tolerance and stability of biocatalysts are very low and vulnerable to damage in organic solvent, its catalytic activity is also affected by the solvent pH and reaction temperature.

 

Application in organic synthesis

1. The application of biocatalysts to the substitution reaction

Many enzymes can be used to catalyze the substitution of alanine, serine, cysteine derivative beta- on carbon and the substitution reaction of methionine and other compounds on r- carbon. Such as O-, n-acetylserine, under the action of enzymes, occurs the substitution reaction of beta- carbon atoms, gets L- cysteine, and then L- cysteine reacts with L- high serine. Under the action of enzymes, hydroxyl on r- carbon is replaced, forming L- cystyl sulfide.

 

Two. The application of biocatalysts to addition and elimination

The addition reaction of carbon carbon double bonds under yeast powder was systematically studied by addition of 1 carbon carbon double bonds with H.-E.Hogberg and P Berglund.

The addition of aldehyde condensation enzyme of 2 carbon and oxygen double bonds can catalyze the aldol condensation reaction. In this class of enzymes, with fructose -1 6- two phosphate aldolase (FDPA) application in organic synthesis was most deeply. For example, in two hydroxyl acetone and 2- hydroxyl propylaldehyde reaction, fructose -1, 6- two phosphate aldolase catalyzed by Furaneol.

 

Three. The application of biocatalysts to the synthesis and hydrolysis of ester

Synthesis of ester 1 ester synthesis of carboxylic acids and alcohols used as raw materials, such as Pseudomonas cepacia lipase modified by PEG can be dissolved in benzene, can be 25 degrees in the effective catalytic terpenols spices (citronellol, geraniol, farnesol, phytol) and short chain carboxylic acids (2-5 carbonate) esterification reaction the yield, 80-95%, synthesis of enzyme can also complete fatty acid monoglyceride, and promote the synthesis of lactone. In addition, transesterification is also an important method for the preparation of esters. When new esters are synthesized by this method, enzymes can be used as catalysts.

 

The hydrolysis of the 2 ester, due to the hydrolysis of the ester under acid or alkaline conditions, may cause the change of the carbon frame and the by-products. The enzyme catalyzed hydrolysis reaction, with mild conditions, does not affect the structure of the carbon frame, so it is particularly important to catalyze the hydrolysis of the ester with enzymes. For example, in acidic or alkaline hydrolysis of Cyclopropanol acetate will occur ring opening reaction of propionaldehyde and generate a aldol products, and the use of pig liver esterase as catalyst in pH 7.5 hydrolysis was cyclopropanol.

 

Four. The application of biocatalysts to the synthesis and hydrolysis of amides

The catalytic reaction of 1 amide and peptide synthetase plays an important role in the formation of amide bonds of penicillin and cephalosporin. For example, under the action of enzymes, 7- aminosaciacetoxy cephalosporins (7 1 ADCA) and D- phenyl GN can be transformed into cephalosporins.

When substrate molecules contain various functional groups, if we want to get a single target product, enzyme is the best catalyst, for example, the synthesis of asparagine.

 

Five. The application of biocatalysts to oxidation and reduction

The oxidation reaction catalyzed by the 1 oxidant enzyme consists of alcohol oxidation, aldehyde oxidation, and the oxidation of ketones to esters. Such as the oxidation of primary and secondary alcohol by horse liver alcohol dehydrogenase, dehydrogenase (HLAD) is one of the new catalytic cyclodextrin derivatives; furfural preparation of furoic acid; oxidation of cyclohexanone ring caprolactone; enzyme can also be used for catalytic dehydrogenation oxidation dehydrogenation of CH - CH bond, with the olefin into microbial cells epoxide, oxidation of amino acids, nitrogen, sulfur and selenium atom oxidation reaction etc..

The reductive reaction of two aldehydes and ketones except for formaldehyde, all aldehydes are dive. Therefore, under the enzyme catalysis, the aldehyde is reduced to get a- carbon as the primary alcohol. For example, a- methyl benzene propanal can be reduced into biological catalytic primary alcohol ketone reduction is an important reaction in the yeast powder under the action, and usually have optical activity reduction products.

 

Application in the food industry

In the food industry, it can be used to reduce viscosity, improve efficiency (or separation efficiency), increase fragrance, and realize biological transformation. In these applications, the immobilized enzyme technology is also widely applied. Currently, the largest immobilized enzyme technology in the world is to produce fructose syrup with immobilized glucose isomerase and glucose as raw material. The specific method is to immobilization of glucose isomerase on two ethylamine ethyl cellulose. The isomerization condition is that the temperature is 20, and PH is 6 - 9. The activity of the immobilized enzyme is up to 90%, and if the activity of the enzyme is reduced, the enzyme can be regenerated by adding a new enzyme.

 

Application in medicine

The application of biocatalysts in medicine has led to new concepts such as artificial cells and artificial organs. Such as the use of microencapsulation technology, enzymes and other biological macromolecules immobilized on 0.2-3um semipermeable membrane, the formation of artificial cells. Because of the isolation of membrane, the enzyme molecules in the capsule do not contact with the extracellular immunoglobulin and are not damaged by hydrolases. So the artificial cell containing one enzyme is the first generation of artificial cells. Using this urease microcapsule, urease artificial cells can transform urine from animal blood to ammonia, and then remove ammonia by immobilized adsorbent, which is the simplest artificial kidney. Using the above microcapsules to form a microcapsule containing multiple enzyme systems, that is, the second generation of artificial cells. The urease, glutamate dehydrogenase and aminotransferase can be immobilized in the microcapsules, so the metabolism of urea and ammonia can start running again and again under the action of this microcapsule. This artificial kidney is a step further. In addition, it is reported that microencapsulated islet cells implanted into diabetic rats can control blood sugar level and treat diabetes, and the rejection can be avoided.

 

Market status

At present, the market for biocatalysts used in the production of fine chemicals is not more than $2-3 billion, only 5% of the total enzyme market. Most of the market for biocatalysts is monopolized or semi monopolized. These catalysts are often provided to an exclusive user. For example, the Do Bi-Sclavo company inItalyproduces an ethoyl urease system that can separate D / L a pair of hydroxyphenyl glycine for the country's Recordati company. Compared with the other part for thorn industry, biological catalyst product sales are scattered, there is almost no certain biological catalyst products in the market more than 10O million dollars. Only B- lactamases (such as penicillin or cephalosporin amidase) are outstanding exceptions, and their market is about 1~2 billion US dollars, accounting for 50% of the biocatalytic market.

 

Prospect

In recent years, biocatalysts have shown a strong growth rate in the fine chemicals market. Biocatalysts are expected to be $200 million to $300 million in the fine chemical industry and the pharmaceutical industry in 2013, with an annual growth rate of 8-9%. The industrial enzymatic synthesis includes steroid and sterol synthesis, alkaloid synthesis, organic acid synthesis, sugar conversion, pharmaceutical polypeptide and protein synthesis, amino acid synthesis, nucleotide synthesis, etc. The world economic cooperation organization (OECD) believes that biocatalysis is the most promising technology for sustainable industrial development. Its rapid development will bring technological innovation and promote the rapid development of productivity. In the past ten years, biocatalyst has gained considerable attention due to the development of the widely used molecular biotechnology tools and high-throughput screening technology. As a result of the above characteristics, biocatalysts will be further favored by the industry producers. By 2013, the share of biotechnology in the global fine chemical industry will jump from the current 15% to 60%, The rate of growth is astonishing and the possibility of achieving it is great. The share of biotechnology in the field of organic fine chemical industry will grow rapidly and will completely replace the use of traditional synthetic production processes in this field. The application of biocatalytic enzyme technology is not only limited to the synthesis of chiral molecules, but also can be used for the production of chiral polymers, especially in the cosmetics industry and food industry.

 

Conclusion and Prospect

Because biocatalyst has the characteristics of high catalytic efficiency, high specificity and less pollution, biocatalysis has been widely applied in the research and development of drugs, just like chemical methods. However, the poor thermal stability of biocatalysts, the vulnerability of pH and the poor tolerance of organic solvents limit the use of biocatalysts in large-scale industrial production. However, with the emergence of new biotechnology, such as directed evolution, it has become a reality to optimize biocatalysts by biotechnology. It is believed that in the near future, biocatalysis can play a greater role in the pharmaceutical industry and make new contributions to the cause of human health. As the rapid development of the mid twentieth Century petrochemical industry has changed people's production and life style, widely used in biological catalysis, biological production process will provide people with better materials and energy to renewable bio based raw materials, will gradually replace the production process of stone materials, become the main chemical production in twenty-first Century, in order to achieve green chemical industry and green production targets.