Chemistry Reference
In-Depth Information
Table 5.6.
Some suppliers of
-galactosidase enzymes
Optimum
pH
Recommended Reaction
temperature (8C)
Catalogue No.
Source
Seikagaku Corporation, Tokyo, Japan
100570
jack bean, lactase
3.5
37
100572
Charonia lampas(a marine
mollusc), lactase
3.6
45
100573
Streptococcus 6646 k, lactase
5.5
40
Sigma-Aldrich Corporation, USA
G1560
Aspergillus oryzae, lactase F
4.0-4.5
30
G1875
bovine liver
7.3
37
G4142
bovine testes
4.4
25
G2513 etc
Escherichia coli, lactase
7.3
37
G3665
Kluyveromyces lactis, lactase
-
-
G3782
Saccharomyces fragilis, lactase
7.2
37
Megazyme International Ireland Ltd, Wicklow, Ireland
E-LACTS
Kluyveromyces fragilis, lactase
6.5-7.0
45
E-BGLAN
Aspergillus niger
4.5
60
Boehringer Mannheim GmbH, Mannheim, Germany
903 345
bovine testes
4.3
37
1 088 718
Diplococcus pneumoniae
6.0-6.5
37
105 031 and
634 395
E. coli overproducer, lactase
7.0
25
Novozymes A/S, Bagsvaerd, Denmark
Lactozym
6.5
37
Enzyme Solutions, Melbourne, Australia
GODO YNL
Kluyveromyces fragilis, lactase
6.5-7.0
37-45
ACIDOLACT
Aspergillus oryzae, lactase
4.5-5.0
50-55
complex and responds to ionic concentrations of a range of elements, namely,
K, Mn and Mg. The enzymes are inhibited by Na
+
and Ca
2+
. Finkelman
(1989) has described the process of strain selection of yeasts for maximal
enzyme activity. Although these yeast lactases suffer from low acid and
temperature tolerance, and operate at neutral pH, this industrial disadvan-
tage is outweighed by the high yields, the ease of cultivation and the estab-
lished safety record of the yeasts. Yeast lactases from Kluyveromyces remain
the most popular source of the enzyme. There is considerable strain-to-strain
variation in the activity of the
-galactosidase present in the strain, and much
research has been conducted to select the best strains.
One of the first descriptions of the use of these enzymes for the produc-
tion of galacto-oligosaccharides is that of Roberts and Pettinati (1957).
