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Enzymatic versus chemical processing of cotton 141

desizing. Amylases as classical desizing agents date back to the early 1900s
when malt extracts from barley containing the active enzymes were applied
to greige fabrics. However, in 1917 bacterial amylases were isolated and
ultimately bacteria became the source for industrial production.
After World War II, the technique of growing bacteria under water in a
fermentation tank allowed mass production of the needed amylases. The
use of Bacillus subtilus by Novo Nordisk for production of amylase was
initiated in the early 1950s (Diderichsen, 1995). Since then, genetic engi-
neering has made possible the development of more heat stable amylases
that can be used over a wider range of pH than conventional products. For
example a regular amylase may be applied at pH 5.5–7.0 and at 25–55 °C.
Amylases for use at medium temperatures can be used in the range of
50–95 °C, whereas high temperature amylases can be used successfully
above 95 °C and also in a pad-steam process (Kuildred, 2006).

6.5.2 Bioscouring using enzymes
Although amylases have been used in desizing for decades, using enzymes

for scouring cotton fiber is a relatively new idea. German research in the
early 1990s alluded to the possibility (Bach and Schollmeyer, 1992; Rossner,
1993; Stohr, 1995). Shortly thereafter, research on cellulases (Tyndall, 1992;
Buschle-Diller and Zeronian, 1992a, 1992b, 1993, 1994; Buschle-Diller et al.,
1994; Buschle-Diller, 1998), suggested that other enzymatic treatments for

cotton fibers might be feasible. From 1996 to 2000, reports appeared that
addressed the possibility of successful scouring of cotton fabrics with
enzymes (Buchert and Pere, 2000; Hardin and Li, 1997; Hartzell and Hsieh,
1998; Lange, 1996; Lange et al., 1998; Li and Hardin, 1996, 1998; Sawada et
al., 1998). Although several enzymes, including cellulases, proteases and
lipases, were examined, pectinases proved to be the most effective. Though
their work was not published at the time, Novo Nordisk (now Novozymes)
had discovered an alkaline pectinase that was particularly effective in creat-
ing water absorbability in cotton fabrics, and they subsequently announced
its commercial availability in 1999 (Lange et al., 1999). This product had two
major advantages over the enzymes that had been examined previously. The
pectate lyase, marketed as ‘BioPrep 3000L’ had very high specifi c activity
and it had its maximum effectiveness at pH 8–10, which made its use com-
patible with subsequent hydrogen peroxide bleaching conditions.
Over the next decade there have been numerous reports dedicated to
what is now called ‘bioscouring’ (Csiszar et al., 2001b; Degani et al., 2002;
Lenting and Zwier, 2002; Lin and Hsieh, 2001; Luis et al., 2006; Tzanov et
al., 2001). As bioscouring was being explored by scientists and industry, it
became necessary to determine the degree to which waxes and pectins
needed to be removed in order to create the desired level of hydrophilicity
in the fabric. A series of combinations of acidic and alkaline pectins and

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