2.3. Enzymatic hydrolysis
2.3.1. Enzymes
For the enzymatic hydrolysis of PPW the following enzyme
preparations from Novozymes A/S, Denmark, were used:
Viscozyme L (V). Viscozyme is a cell wall degrading enzyme
complex from Aspergillus aculeatus. The activity of Viscozyme
L was 120 Fungal Beta-Glucanase Units (FBGU)/ml. One FBG is
the amount of enzyme required under standard conditions
(30 C, pH 5.0, reaction time 30 min) to degrade barley a-glucan
to reducing carbohydrates with a reduction power corresponding
to 1 lmol glucose/min.
Ternamyl 120 L (T). Ternamyl 120 L is a heat-stable amylase
from B. licheniformis. The enzyme activity was 120 KNU/g (kilo
novo units of a-amylase). KNU is the amount of enzyme
required to break down 5.26 g of starch per hour according to
Novozyme’s standard method for the determination of
a-amylase.
Liquozyme Supra (L). Liquozyme Supra is a heat-stable a-amylase
from Bacillus lichneniformis. The enzyme activity was 200
KNU/g.
Celluclast 1.5 L (C). Celluclast 1.5 L is a liquid cellulase preparation
with an enzyme activity of 1500 NCU/g. One Novo Cellulase
Unit (NCU) is the amount of enzyme which, under standard
conditions, degrades carboxymethylcellulose to reducing carbohydrates
with a reduction power corresponding to 1 lmol glucose
per minute. It is produced by submerged fermentation of a
selected strain of Trichoderma reesei.