Industrial Biotransformations

stability/months
14
12
10
8
6
4
2
0
1.2 From Gastric Juice to SweetzymeT – The History of Enzymatic Biotransformations
Sweetzym E
Record: 687 days at ideal conditions
Sweetzym Q
Sweetzym T
1976–1984 1985–1990 1990–1998
Fig. 1.23 Improved biocatalyst stability by biocatalyst engineering at NOVO.
plant with a capacity of 10 tons per day is situated in Milan. The entrapped enzyme is
lactase obtained from yeast and the reaction is performed batchwise at low temperature.
Lactase hydrolyzes lactose, a sugar with poor solubility properties and a relatively low
degree of sweetness, to glucose and galactose (Fig. 1.24).
OH
OH
HO
O
OH
O
O
OH
OH
β-galactosidase
OH
OH
OH
HO
O
OH
+
OH
OH
HO
HO
O
OH
OH
lactose
HO
galactose glucose
Fig. 1.24 b-Galactosidase catalyzed hydrolysis of lactose to galactose and glucose.
After the processed milk reaches the desired degree of hydrolysis of lactose, it is separated
from the enzyme fibers, sterilized and sent for packing and distribution. SNAMprogetti’s
process facilitates the manufacture of a high-quality dietary milk at low cost. This
milk has remarkable digestive tolerance, pleasant sweetness, unaltered organoleptic
properties and a good shelf-life. It does not contain foreign matter. The industrial plant is
shown in Fig. 1.25.
Penicillin G, present in Penicillium notatum and discovered by Fleming in 1929, revolutionized
chemotherapy against pathogenic microorganisms. Today, b-lactam antibiotics
such as penicillins and cephalosporins are used very widely. Thousands of semisynthetic
b-lactam antibiotics are being synthesized to find more effective compounds. Most of
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