Our previous work demonstrated that ethylenediamine-tetra-acetic acid (EDTA) markedly enhances the apparent activity of commercial xylanase and pectinase enzymes in cotton bioscouring, accelerating degradation and removal of impurities. In this study, we explore how EDTA can improve the efficiency of the enzyme process in cotton bioscouring. The effects of EDTA on the enzyme action and degradation of seed-coat fragments-the most resistant natural impurities of cotton to be degraded in bioscouring-are investigated. Results show that application of EDTA in different concentrations does not inhibit the main activities of the enzymes investigated. Thus, the pectinase activity of Viscozyme 120L and the xylanase activity of Pulpzyme HC remain almost unchanged. On the other hand, EDTA modifies the substrate structure by removing the calcium ions from the cross bridges that link the macromolecules in pectin to one another or pectin to other polysaccharides. While EDTA pretreatment significantly decreases the efficiency of enzymatic hydrolysis monitored by reducing sugar liberation, simultaneous application of EDTA and enzyme in one treatment bath largely accelerates the degree of hydrolysis, indicating a synergistic effect of enzyme and EDTA.Recent results in textile biotechnology prove that enzymes can be used effectively in the preparatory processes of natural cellulosic fibers like cotton and flax. In bioscouring cotton, noncellulosic "impurities" (i.e., waxes, pectic substances, proteins, lignin-containing, and coloring materials, etc.) can be removed mainly by hydrolytic enzymes such as pectinase, xylanase, and cellulase. Enzymatic degradation of pectin accelerates the removal of waxy materials from the cotton primary wall, thus producing water-wettable cotton. The bioprocess has several advantages over traditional chemical scouring. Enzymes operate under mild conditions (pH, temperature) with low water consumption and act only on specific substrates. On the other hand, traditional alkaline scouring with hot caustic soda is unquestionably an energy-, water-, and chemical-intensive process [17].Enzymes can also be used with good results in retting flax. Attempts have been made to eliminate the disadvantages of the current commercial method of field retting and to improve the quality and consistency of the fibers. As a result of research focused on the development of alternative retting methods, a specific enzymeretting method has been worked out. In that process, pectinase-rich enzyme mixtures are used to separate the fibers from nonfiber tissues and to produce quality fibers from flax. Enzyme retting is more controllable and environmentally friendly than conventional dew retting [1,20].In both bioscouring of cotton and enzyme retting of flax, degradation of pectic substances is the most essential process. Pectin generally builds up from D-galacturonic acid residues, which are present in a linear backbone. Some of the carboxylic acid groups are esterified with methanol. The pectic polymer can be called a block copoly...

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Enzymatic (cellulase, pectinase, xylanase) and simple buffer treatments in the presence of a nonionic surfactant improve water wettability of fabrics to a level equal to conventional alkaline scouring. Caustic scoured fabric is significantly lighter and less colored than all the biopretreated samples. Application of a hydrogen peroxide bleaching subsequent to the biopretreatment is beneficial because it reduces the great color differences between conventionally scoured and biopretreated samples. Bleachability of the pretreated fabrics is better than that of the conventionally scoured sample. Biopretreated fabrics can be dyed with a reactive dye subsequent to the enzymatic treatment without further oxidative bleaching. At higher dye concentrations ( i.e., 1 or 2%), there is no perceptible color difference between the biopretreated and alkaline scoured fabrics in the dyed state. In pale and medium dyeings, however, the color difference is great and perceptible. Bleaching applied subsequent to bioscouring significantly decreases the color difference between the dyed samples pretreated in different ways. None of the pretreatments causes uneven dyeing. Wash fastness of the dyed samples is excellent and unrelated to the pretreatment method.Preparation and bleaching are among the most energyand chemical-intensive steps in traditional cotton finish-

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Solubilization of lignin and carbohydrates from the lignin-holocellulose structure of cotton seed-coat fragments was investigated by UV/VIS spectrometry. Xylanase (Pulpzyme HC) pre-treatment partially destroyed the lignocellulosic structure of the seed-coat fragments, producing reducing sugars and soluble lignin in the supernatant. Furthermore, the pre-treatment by enzyme enhanced the delignification in the subsequent alkaline scouring process and increased the lightness of the substrate.