0 16 32 48 64 80 96 112 128 144 160 1760

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Some of the most important processes based on

immobilized enzymes and used commercially are as

follows:

1. High Fructose Corn Syrup

2. Immobilized Raffinase

3. Immobilized Invertase

4. Immobilized Lactase

5. Antibiotic Production

6. Preparation of Acrylamide.

The advantages offered by immobilized enzyme

systems include the following:

(i) use of continuous processes, which reduces the plant size

to nearly one-half,

(ii) easy, cheap, off-site fabrication of plants,

(iii) greatly increased productivity/unit of enzyme used, and

(iv) often process advantages.

The various important processes based on immobilized

enzymes and used commercially are briefly described below

and listed in Table 15.5.

1. High Fructose Corn Syrup:

D-glucose is only 70% as sweet as sucrose and is

comparatively less soluble in water. Fructose, on the other

hand, is 30% more soluble than sucrose and is twice as

soluble as glucose at lower temperatures. Therefore, glucose

syrup is treated with glucose isomerase to produce high

fructose syrup: 42% fructose syrup is good enough for many

uses, but for soft drinks a 55% fructose syrup is required.

Glucose isomerase is obtained from Actinoplanes

missouriensis, Bacillus coagulans and Streptomyces spp. It is

remarkably thermostable and acts at very high substrate

concentrations. It is used in immobilized state obtained by

cross-linking with glutaraldehyde; in some cases, a protein

diluent may be added. The process is continuous using a

packed bed reactor.

The glucose syrup is purified to remove impurities,

concentrated to 35-45% dry solids and heated to 55-60°C

(pH 7.5-8). Mg2+ and Co2+ are needed by the enzyme as

cofactors; Co2+ is usually immobilized with the enzyme, while

Mg2+ is added into the syrup.

Syrup flow is adjusted to obtain about 42-46% (w/w

fructose). The half-life of most enzymes (at 60°C) is between

50 and 100 days; the enzyme is discarded after 3 half-lives

during which 1 kg enzyme will produce 10-11 tons of 42%

fructose syrup.

The pH of syrup is lowered to 4.5, and the syrup purified and

evaporated to about 70% solids. The 55% fructose syrup is

prepared as follows: fructose is separated from the syrup by

using vast chromatographic columns of zeolite or a suitable

resin, and mixed with 42% fructose syrup. The present

market of high fructose syrup is over 5 million tons, and still

expanding; it is the major application of immobilised enzyme

technology.

https://books.google.ca/books?id=jIwHmPS1AYQC&pg=PA261&lpg=PA261&dq=covalent+immobilization+glucose+fructose&source=bl&ots=Ug35EpPhS-&sig=7uIpuKoN_pZxoMx5NpBpPWwa144&hl=en&sa=X&ei=0AAJVeG8BMqdygTK7YG4Aw&ved=0CDwQ6AEwBQ#v=onepage&q=covalent%20immobilization%20glucose%20fructose&f=false

https://books.google.ca/books?id=zfZGAAAAQBAJ&pg=PA220&lpg=PA220&dq=covalent+immobilization+glucose+fructose&source=bl&ots=GmSSbYvOcs&sig=amaiKQkTlHYHknsXVaRufFXwb5s&hl=en&sa=X&ei=0AAJVeG8BMqdygTK7YG4Aw&ved=0CDQQ6AEwAw#v=onepage&q=covalent%20immobilization%20glucose%20fructose&f=false

http://www1.lsbu.ac.uk/water/enztech/hfcs.html

https://www.google.ca/search?q=immobilized+enzymes+reactor+high+fructose+corn+syrup&espv=2&biw=1366&bih=624&source=lnms&tbm=isch&sa=X&ei=avoIVaOBBoSayAS6tYGQAg&ved=0CAYQ_AUoATgU

http://aklyosov.home.comcast.net/~aklyosov/Volume4.htm

http://www1.lsbu.ac.uk/water/enztech/reactors.html

http://www.eng.umd.edu/~nsw/ench485/lab13.htm

http://textbookofbacteriology.net/growth.html