Journal of Biotechnology 89 (2001) 271 – 279 Enzymes and chelating agent in cotton pretreatment Emı ´lia Csisza ´r *, Anita Losonczi, George Szaka ´cs, Istva ´n Ruszna ´k, La ´szlo ´ Bezu ´ r, Johanna Reicher Budapest Uniersity of Technology and Economics, PO Box 91, H-1521 Budapest, Hungary Received 26 June 2000; received in revised form 10 January 2001; accepted 17 April 2001 Abstract Desized cotton fabric and cotton seed-coat fragments (impurities) have been treated with commercial cellulase (Celluclast 1.5 L), hemicellulase – pectinase (Viscozyme 120 L) and xylanase (Pulpzyme HC) enzymes. Seed-coat fragments hydrolyzed much faster than the cotton fabric itself. This relative difference in hydrolysis rates makes possible a direct enzymatic removal of seed-coat fragments from desized cotton fabric. Addition of chelating agents such as ethylenediamine-tetra-acetic acid (EDTA) markedly enhanced the directed enzyme action. Pretreatments carried out in acidic solution at pH 5 increased the lightness of seed-coat fragments, contrary to the samples treated in neutral medium at pH 7. Alkaline scouring resulted in darker seed-coat fragments except for the samples pretreated with Pulpzyme HC plus EDTA. This effect is similar to that observed in the biobleaching process in pulp and paper industry. © 2001 Elsevier Science B.V. All rights reserved. Keywords: Bioscouring; Cellulases; Chelating agent; Cotton; Hemicellulases; Seed-coat fragments www.elsevier.com/locate/jbiotec 1. Introduction The serious waste water pollution caused by textile finishing has oriented recent research to- wards application of enzymes in wet processes. Cellulases, hemicellulases and pectinases acting on native cellulosic fibres (cotton, flax, hemp, jute, etc.) became the target enzymes in bioprocessing (Lange, 1993). The production of ‘aged’ denim garments with cellulases is the most successful enzyme process that has emerged in the textile industry in the last decade. Biofinishing or biopo- lishing represents another application of cellulases for nondenim cellulosic fabrics and garments (Cavaco-Paulo, 1998). In the environmentally- friendly process, cellulosic fabrics are subjected to a treatment with cellulolytic enzymes, and the action of cellulases removes small loose fibre ends that protrude from the fabric surface. Recent results indicate that enzymes (mainly cellulases and several noncellulolytic enzymes such as lipases, proteases and pectinases) may be used effectively in the cleaning procedure of cot- ton. In the traditional scouring process — which is energy and chemical intensive — concentrated sodium hydroxide solution and additional hydro- gen peroxide and/or sodium hypochlorite solu- tions are applied for removing the impurities from * Corresponding author. Tel.: +36-1-463-1423; fax: +36- 1-463-3648. E-mail address: emi.oct@chem.bme.hu (E. Csisza ´r). 0168-1656/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved. PII:S0168-1656(01)00315-7