Industrial Biotransformations

a-Amylase / Amyloglucosidase
Bacillus licheniformis / Aspergillus niger
O
1) Reaction conditions
pH: liquefying: 6.0 – 6.5 / glucosidation: 4.2
T: 115°C – 95 °C / 60 °C
medium: aqueous
reaction type: O-glucosyl-bond hydrolysis (endo / exo)
catalyst: solubilized enzyme
enzyme: 1,4-α-d-glucan glucanohydrolyse (α-amylase, glycogenase) / glucan 1,4-a-glucosidase
(glucoamylase, amyloglucosidase)
strain: Bacillus licheniformis / Aspergillus niger
CAS (enzyme): [9000–90–2] / [9032-08-0]
2) Remarks
O
CH 2OH
O
OH
OH
CH2OH
O
OH
OH
CH 2OH
O
OH
O
OH
O
OH
O O O
O
OH
● The process is a part of the production process for high fructose corn syrup (see page 508).
● After several improvements this process provides an effective way for an important, low-cost
sugar substitute derived from grain.
● At various stages enzymes are employed in this process.
1
CH 2
OH
CH 2OH
EC 3.2.1.1/3.2.1.3
1 = starch
2 = glucose
E1 = α -amylase
E2 = glucoamylase Several companies
Fig. 3.2.1.1/3.2.1.3 – 1
CH2OH
O
OH
O
OH
● The corn kernels are softened by treatment with sulfur dioxide and lactic acid bacteria to separate
oil, fiber and proteins. The enzymatic steps are cascaded to yield the source product for
the invertase process after liquefaction in continuous cookers, debranching and filtration.
● Since starches from different natural sources have different compositions the procedure is not
unique. The process ends if all starch is completely broken down to limit the amount of oligomers
of glucose and dextrins. Additionally, recombination of molecules has to be prevented.
332
O
OH
E1
+H2O
oligomer units
+H2O
E2
CH2OH O
OH
OH OH
OH
2