Page 74 - Advances in Textile Biotechnology

Developments in enzymatic textile treatments 53

30 A, before pectinase incubation
C
ΔPectin removal (%) 20 B, after pectinase incubation B

C, during pectinase incubation

10
A

0
0 2 4 6 8 10 12 14 16
Time (min)
2.15 Experimentally determined effect of ultrasound on the
performance of enzymes.

of acoustic cavitation. The ultrasonic wave creates during its rarefaction
period locally tiny bubbles that collapse during the compression phase.
These collapses create micro liquid jets that can penetrate deeply into the
pores of fabrics. Therefore, ultrasound can be seen as a source of mechani-
cal energy to accelerate the mass transfer processes in the pores of fabrics.
It has been found that ultrasound also accelerates the performance of
enzymes in enzymatic textile treatment processes (Agrawal et al., 2007).
Figure 2.15 shows the results of some experiments.
To determine the effect of ultrasound on the removal of pectin by the
enzyme pectinase, three experiments were performed: ultrasound applied
before, after and during the enzymatic treatment. From Fig. 2.15, it is clear
that applying ultrasound before the enzymatic treatment did not affect the
enzymatic performance, whereas applying it after the enzymatic treatment
led to a better performance. This is because of the more rapid removal of
the enzymatic reaction products. Applying ultrasound during the enzymatic
incubation resulted in a large effect on the performance. This can be
explained by a fast transfer of the enzymes to the capillary liquid, a fast
refreshment of the capillary liquid during the adsorption of enzymes at the
surface and a fast removal of the reaction products. Therefore, ultrasound

can be seen as a very effective and efficient way to apply mechanical energy
to the enzymatic treatment of textiles and fabrics.

2.8 Future trends

It has been shown here that mechanical energy plays a dominant role in
the performance of enzymes in textile treatment processes. Therefore, it is

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