NZ235671A

NZ235671A - Bleaching agent and process for inhibiting dye transfer during washing and

Info

Publication number: NZ235671A
Application number: NZ23567190A
Authority: NZ
Inventors: Tube Damhus; Ole Kirk; Gitte Pedersen; Manuel Garcia Venegas
Original assignee: Procter & Gamble; Novo Nordisk As
Priority date: 1990-10-12
Filing date: 1990-10-12
Publication date: 1994-02-25

Description

<div class="application article clearfix" id="description"> New Zealand Paient Spedficaiion for Paient Number £35671 t 235671 Priority C;t;{s): . 1%:M Coi'fvc''^ Speu-icotion Filed: J7r\ n AlWSl.^S* • Publication Date: ...??. ! >■' I.- ... ■' M 1 - r* /"V^-— 5'' :■ .) . , ' _ ' , ", ' L v ■<<>/' il./ [i •- .tf ». vi j L v. .. NEW ZEALAND PATENTS ACT, 1953 No.: Date: COMPLETE SPECIFICATION ■ v ''' \ •<r OV- V* V? "DYE TRANSFER INHIBITION" j[ /<?q ' i </We, THE PROCTER & GAMBLE COMPANY, a corporation organised and existing under the laws of the State of Ohio, USA, of One Procter & Gamble Plaza, Cincinnati, Ohio 45202, USA, and N0V0-N0RDISK A/S, of Novo-Alle, DK-2880 Bagsvaerd, DENMARK, a Danish Company. hereby declare the invention for which "f / we pray that a patent may be granted to rap/us, and the method by which it is to be performed, to be particularly described in and by the following statement: - - 1 - (followed by page la) la. 235 07 1 ^ DYE TRANSFER INHIBITION FIELD OF INVENTION The present invention relates to an enzymatic process for inhibiting the transfer of dya from a dyed fabric to another fabric during washing, to a bleaching agent for use in the process, and to a process for bleaching dyes in solution. BACKGROUND OF THE INVENTION The use of bleaching agents in washing procedures and as constituents of detergent compositions is well known in the art. Thus, bleaching agents are incorporated in or sold as constituents of a major part of tho coramaroially available detor-gent compositions. Important conventional bleaching agents incorporated in detergent compositions are compounds which act as precursors of hydrogen peroxide formed in the course of the washing procedure. Perborates and percarbonates are the moBt important examples of compounds which are employed as bleaching agents and which exert a bleaching effect in this fashion. The detailed mechanism of bleaching by means of these bleaching agents is not known at present, but it is generally assumed that the hydrogen peroxide formed during washing converts coloured substances (responsible for Btains on fabric) into non-coloured materials by oxidation and that anmp nviriaHnn nf the rnlnnreri substance* may aleo tako plaae due to their direct interaction with perborate or percar-bonate. One drawback of these commonly used bleaching agents is that they are not particularly efficient at the lower temperatures at which coloured fabrics are usually washed. Their efficiency may be enhanced by the use of activators (e.g. organic acid anhydrides, esters or imidas) which give rise to the formation of peracids. 2 235671 Apart from being employed for bleaching Btain3 on fabric, such conventional bleaching agents have also been suggested for preventing surplus dye3 from coloured fabrics which leach from the fabrics when these are washed from being deposited on other fabrics present in the same wash (this phenomenon is commonly known as dye transfer). The problem of dye transfer, of course, is most noticeable when white or light-coloured fabrics are washed together with fabrics of a darker colour from which dye is leached during washing. It has, however, been found that the currently employed bleaching agents, whether activated or not, are not particularly effective in inhibiting dye transfer, possibly because the rate at which they oxidize dissolved dyes is rather slow. On the other hand, peracids formed from the bleaching activators are active against dyes on fabric so as to cause discolouration of the fabric in question. US 4,077,768 disoloses the use of iron porphin, haemin chloride or iron phthalocyanine, or derivatives thereof together with hydrogen peroxide for dye transfer inhibition. It is indicated that these compounds act as catalysts for the bleaching process whereby they provide an increase in the rate at which dissolved dyes are oxidised (or, in other words, bleached) without causing any discolouration of the dye in the fabric. However, these catalysts are destroyed by the presence of excess hydrogen peroxide which makes it necessary to control the release of hydrogen peroxide so that only the quantity of hydrogen peroxide needed to effect the inhibition of dye transfer .should be. present in the wash water at any time. Such controlled release of the bleaching agent may be difficult to achieve. 3 23 5 6 7 SUMMARY OF THE INVENTION It has surprisingly been found possible to bleach coloured substances leached from dyed textiles or from textiles soiled with a colourant in a solution of wash liquor thereby preventing the coloured substance in question from being da-posited on other textiles in the wash liquor, when enzymes utilizing hydrogen peroxide or molecular oxygen for the oxidation of organic or inorganic substances, including coloured substances, are added to the wash liquor. Such enzymes are usually termed peroxidases and oxidases, respectively. Accordingly, the present invention relates to a process for inhibiting the transfer of a textile dye from a dyed fabric to another fabric when said fabrics are washed and/or rinsed together in a wash liquor, the process comprising adding an enzyme exhibiting peroxidase activity or an enzyme exhibiting a suitable oxidase activity to the wash liquor in which said fabrics are washed and/or rinsed. In the present context, the term "enzyme exhibiting peroxidase activity" is understood to indicate an enzyme with a mode of action similar to that of a peroxidase and will be used synonymously therewith. Similarly, the term "enzyme exhibiting a suitable oxidase activity" is understood to indicate an enzyme with a similar mode of action to that of an oxidase and is meant to be synonymous therewith in the following. Suitable oxidases include those which act 'on aromatic compounds such as phenols and related substances. One or more substrates for the enzyme may also be added at the beginning of or during the washing and/or rinsing process, in particular when the enzyme is one with peroxidase activity as, in the case of oxidases, molecular oxygen is usually present in sufficient quantities. When the enzyme used in the process of the invention is a peroxidase, hydrogen peroxide or a precursor of hydrogen peroxide, preferably perborate or percarbonate, will therefore typically be added 4 235671 as the substrate. It is well recognized in the art (cf. for instance B.C. Saunders et al., Peroxidase. London, 1964, p. 10 ff.) that peroxidases act on various amino and phenolic compounds resulting in the production of a colour. In view of this, it must be considered surprising that peroxidases (and certain oxidases) may also exert an effect on coloured substances in solution such that dye transfer is inhibited. While the mechanism governing' the ability of these enzymes to effect dye transfer inhibition has not yet been elucidated, it is currently believed that the enzymes act by reducing hydrogen peroxide or molecular oxygen and oxidizing the coloured substance (donor substrate) dissolved or dispersed in the wash liquor, thereby either generating a colourless substance or providing a substance which is not adsorbed to the fabric. This reaction is shown in Reaction Scheme 1 below (for peroxidases) and Reaction Scheme 2 below (for oxidases useful for the present purpose) Reaction Scheme 1: Donor substrate + H202 -> oxidized donor + 2 H2O Reaction Scheme 2; Donor substrate + O2 -> oxidized donor + 2 H2O It has previously been reported that peroxidases may decolourize certain pigments (cf. for instance W. Schreiber, Biochem. Biophvs. Res. Commun. 63 (2), 1975, pp. 509-514, describing the degradation of 3-hydroxyflavone by horseradish peroxidase; A. Ben Aziz, Phvtochemistrv 10. 1971, pp. 1445-1452, describing the bleaching of carotene by means of a peroxidase; and B.P. Wasserman, J. Food Soi. 49. 1984, pp. 536- 235 67 5 538, describing the decolourization of betal&in by horseradish peroxidase). Ben Aziz et al. and Wasserman et al. present the bleaching action of peroxidases on carotene and betalain, respectively, as a problem when using these pigments as food colourants, which problem must be counteracted by including an antioxidant in the foodstuff in question. Thus, they do not consider the peroxidase-mediated bleaching of these pigments to have any practical utility in itself. Although these publications describe test methods whereby the respective pigments are incubated with the enzyme in solution, the pigments in question are all pure compounds of natural origin and are also readily bleached by the bleaching agent3 usually incorporated in modern detergents (cf. for instance Second World Conference on Detergents. A.R. Baldwin (ed.), American Oil Chemist's Society, 1978, pp. 177-1B0). Contrary to this, the commonly used textile dyes, when dissolved or dispersed in wash liquors, are generally resistant to oxidation by atmospheric oxygen and also, to a greater or lesser extent, to the bleaching agents currently used in detergents which, as noted in US 4,077r768, are inefficient dye transfer inhibitors as they act too slowly on the dispersed or dissolved dyes. Under these circumstances, it must be considered surprising that the enzymes used in the present process are, in fact, able to oxidize these dyes. Other commonly used bleaching agents which may have an effect on textile dyes in solution or dispersion, e.g. hypochlorite, also attack dye on or in the fabrics, resulting in discolouration thereof. It is an important advantage of the enzymes used in the process of the invention that they do not cause any appreciable colour degradation in the dyed fabric itself. A comprehensive catalogue of commonly used textile dyes, both synthetic (such as azo dyes) and natural or nature-identical (by which is meant a substance which is produced synthetically, but which in structure and properties is identical to the natural compound), e.g. indigo, is found in the color Index. 6 235671 3rd ed. Vol. 1-6. In another aspect, the present invention relates to a process for bleaching textile dyes in solution or dispersion, the process comprising adding an enzyme exhibiting peroxidase activity or an enzyme exhibiting a suitable oxidase activity to said solution or dispersion. It is contemplated that, apart from having utility in inhibiting dye transfer during a washing or rinsing process, the ability of these enzymes to bleach dyes in solution may alBo make them useful for treating waste water from the textile industry forming part of a waste disposal process. In a further aspect, the present invention relates to a bleaching agent for inhibiting the transfer of a textile dye from a dyed fabric to another fabric when said fabrics are washed and/or rinsed together, the agent comprising an enzyme exhibiting peroxidase activity or an enzyme exhibiting a suitable oxidase activity. Apart from this utility, the bleaching agent may also be employed in the treatment of waste water from the textile and possibly also other industries, as indicated above. DETAILED DISCLOSURE OF THE INVENTION Examples of suitable oxidases which act on aromatic compounds, in particular phenolic, e.g. polyphenolic, are catechol oxidase (EC 1.10.3.1) or laccase (EC 1.10.3.2). For the sake of convenience, such oxidases, and peroxidases are collectively termed bleaching enzymes in the following. Bleaching enzymes which may be employed for the present purpose may be isolated from and are producible by plants (e.g. horseradish peroxidase) or microorganisms such as fungi or bacteria. Some preferred fungi include strains belonging to the subdivision Deuteromycotina, class Hyphomycetes, e.g. Fu-sarium, Humicola. Tricoderma. Mvrothecium. Vertlclllum. 7 235 07 Arthromvces, caldarlomvces, Plocladluro, EgifrgUlgU* Cladosporlum or Dreschlera. in particular Fusariuio oxyspormn (DSM 2672), Humicola insolens, Trlcoderma resil, MYfothesiUTO verrucana (IFO 6113), Vertlclllua alboatrum. Verticilium dahlie. Arthromvces ramosus (FERM P-7754), GaldarlSBlYSfia fumaao. Ulocladium chartarum. Eabellisia alii or Dreschlera halodeB. Other preferred fungi include strains belonging to the subdivision Basidiomycotina, class Basidiomycetes, e.g. coprinus. Phanerochaete. Coriolus or Trametes, in particular Coprinus cinereus f. microsporus (IFO 8371) , Coprinus macrorhlzus. Phanerochaete chrvsosporium (e.g. NA-12) or Coriolus versicolor (e.g. PR4 28-A). Further preferred fungi include strains belonging to the subdivision Zygomycotina, class Hycoraceae, e.g. Rhizopus or Mucor. in particular Hucor hiemalls. Some preferred bacteria include strains of the order Actino-mycetales, e.g. Streptomvces spheroides (ATTC 23965), Strep-tonivces thermoviolaceus (IFO 12382) or Streptoverticilium verticillium ssp. varticillium. Other preferred bacteria include Bacillus pumillus (ATCC 12905) , Bacillus stearothermophilus, Rhodobacter sphaeroides, Rhodoaonas palustri, Streptococcus las£is, Pseudomonas purrocinia (ATCC 15958) or Pseudomonas nuqgSSqqna (NRRL fill) . Other potential sources of useful bleaching enzymes (in particular peroxidases) are listed in B.C. Saunders et al., op. 'cit.. pp. 41-43. Methods of producing enzymes to be used according to the invention are described in the art, cf. for example FEBS Letters 1625, 173(1), Applied and Environmental Microbiology, 8 235 67 1 Feb. 1985, pp. 273-278, Applied Microbiol. Blotechnol. 26. 1987, pp. 158-163, Biotechnology Letters 9/5). 1987, pp. 357-360, Nature 326. 2 April 1987, FEBS Letters 4270. 209/2). p. 321, EP 179 486, EP 200 565, GB 2 167 421, EP 171 074, and Agric. Biol, Chem. 5Qfl). 1986, p. 247. Particularly preferred bleaching enzymes are those which are active at the typical pH of washing liquors, i.e. at a pH of 6.5 - 10.5, preferably 6.5 - 9.5, and most preferably 7.5-9.5. Such enzymes may be isolated by screening for the relevant enzyme production by alkalophilic microorganisms, e.g. using the ABTS assay described in JR.E. Childs and W.G. Bards-ley, Biochera. J. 145. 1975, pp. 93-103. Other preferred bleaching enzymes are those which exhibit a good thermostability as well aa a good stability towards commonly used detergent components such as non-ionic, cationic, or anionic surfactants, detergent builders, phosphate etc. Another group of useful bleaching enzymes are haloper-oxidases, such as chloro- and broraoperoxidases. The bleaching enzyme may furthermore be one which is producible by a method comprising cultivating a host cell transformed with a recombinant DNA vector which carries a DNA sequence encoding said enzyme as well as DNA sequences encoding functions permitting the expression of the DNA sequence encoding the enzyme, in a culture medium under conditions permitting the expression of the enzyme and recovering the enzyme from the culture. A DNA fragment encoding-the enzyme may, for instance, be isolated by establishing a cDNA or genomic library of a microorganism producing the enzyme of interest, such as one of the organisms mentioned above, and screening for positive clones by conventional procedures such as by hybridization to oligonucleotide probes synthesized on the basis of the full or 9 235 67 partial amino acid sequence of the enzyme, or by selecting for clones expressing the appropriate enzyme activity, or by selecting for cloneB producing a protein which is reactive with an antibody against the native enzyme. Once selected, the DNA sequence may be inserted into a suitable replicable expression vector comprising appropriate pro-motor, operator and terminator sequences permitting the enzyme to be expressed in a particular host organism, as well as an origin of replication enabling the vector to replicate in the host organism in question. The resulting expression vector may then be transformed into a suitable host cell, such as a fungal cell, preferred examples of which are a species of Aspergillus. most preferably Aspergillus orvzae or Aspergillus nlger. Fungal cells may be transformed by a process involving protoplast formation and transformation of the protoplasts followed by regeneration of the cell wall in a manner known per se. The use of Aspergillus as a host microorganism is described in EP 238,023 (of Novo Industri A/S), the contents of which are hereby incorporated by reference. Alternatively, the host organisms may be a bacterium, in particular strains of Streptomvces and Bacillus, or E. coli. The transformation of bacterial cells may be performed according to conventional methods, e.g. as described in T. Maniatis et al., Molecular cloning; A Laboratory Manual. Cold Spring Harbor, 1982. The screening of appropriate DNA sequences and construction of vectors may also be carried out by standard procedures, cf. T. Maniatis et al., oo. cit. The medium used to cultivate the transformed host cells may be any conventional medium suitable for growing the host cells in question. The expressed enzyme may conveniently be 10 235 6 7 1 secreted into the culture medium and may be recovered therefrom by well-known procedures including separating the cells from the medium by centrifugation or filtration, precipitating protein&ceous components of the medium by means of a salt such as ammonium sulphate, followed by chromatographic procedures such as ion exchange chromatography, affinity chromatography, or the like. When the bleaching enzyme employed in the process of the in-vention is a peroxidase, it may be desirable to utilize an enzymatic process for hydrogen peroxide formation. Thus, the process according to the invention may additionally comprise adding an enzymatic system (i.e. an enzyme and a Bubstrate therefor) which is capable of generating hydrogen peroxide at the beginning or during the washing and/or rinsing process. one such category of hydrogen peroxide generating systems comprises enzymes which are able to convert molecular oxygen and an organic or inorganic substrate into hydrogen peroxide and the oxidized substrate, respectively. These enzymes produce only low levels of hydrogen peroxide, but they may be employed to great advantage in the process of the invention as the presence of peroxidase ensures an efficient utilization of the hydrogen peroxide produced. Preferred hydrogen peroxide-generating enzymes are those which act on1 cheap and readily available substrates which may conveniently be included into detergent compositions. An example of such a substrate is glucose which may be utilized for hydrogen peroxide production by means of glucose oxidase. Other suitable oxidases are urate oxidase, galactose oxidase, alcohol oxidases, amine oxidases, amino acid oxidase and cholesterol oxidase. It has surprisingly been found that the addition of another oxidisable substrate (for the bleaching enzyme used in the process of the invention) at the beginning or during the 11 235 6 7 1 washing and/or rinsing process may enhance the dye transfer inhibitory effect of the bleaching enzyme employed. This is thought to be ascribable to the formation of short-lived radicals or other oxidised states of this substrate which participate in th® bleaching or other modification of the coloured substance. Examples of such oxidisable substrates are metal ions, e.g. Mn++, halide ions, e.g. chloride or bromide ions, or organic compounds such as phenols, e.g. p-hydroxycinnamic acid or 2,4-dichlorophenol. other examples of phenolic compounds which may be used for the present purpose are those given in M. Kato and S. Shimizu, Plant Cell Phveiol. li(7)t 1985, pp. 1291-1301 (cf. Table l in particular) or B.C. Saunders et al., op. cit., p. 141 ff. The amount of oxidisable substrate to be added is suitably between about 1/jM and ImM. In the process of the invention, the bleaching enzyme will typically be added as a component of a detergent composition. As such, it may be included in the detergent composition in the form of a non-dusting granulate, a liquid, in particular a stabilized liquid, or a protected enzyme. Non-dusting granulates may be produced, e.g., as disclosed in US 4,106,991 and 4,661,4 52 (both to Novo Industri A/S) and may optionally be coated by methods known in the art. Liquid enzyme preparations may, for instance, be stabilized by adding a polyol such as propylene glycol, a sugar or sugar alcohol, lactic acid or boric acid according to established methods. Other enzyme stabilizers are well known in the art. Protected enzymes may be prepared according to the method disclosed in EP 238,216. The detergent composition may also comprise one or more substrates for the enzyme. The detergent composition will additionally comprise surfactants which may be of the anionic, non-ionic, cationic, amphoteric, or zwitterionic type as well as mixtures of these surfactant classes. Typical examples of anionic surfactants are linear alkyl benzene sulfonates (LAS), alpha olefin sul- 12 23 5 671 fonates (AOS), alcohol ethoxy sulfates (AES) and alkali metal salts of natural fatty acids. The detergent composition nay further contain other detergent ingredients known in tha art as e.g. builders, anti-corrosion agents, sequestering agents, anti-soil redeposition agents, perfumes, enzyme stabilizers, etc. It is at present contemplated that, in the process of the invention, the bleaching enzyme may be added in an amount of 0.01-100 mg enzyme per liter of wash liquor. The detergent composition may be formulated in any convenient form, e.g. as a powder or liquid. The enzyme may be stabilized in a liquid detergent by inclusion of enzyme stabilizers as indicated above. Liquid detergents may further include stabilized hydrogen peroxide precursors. Usually, the pH of a solution of the detergent composition of the invention will be 7-12 and in some instances 7.0-10.5. Other detergent enzymes such as proteases, lipases or amylases may be included in the detergent composition. Examples. Dyes were purchased from Aldrich Chemicals. Peroxycarboxylic acid references were synthesized according to W.E. Parker, C. Ricciuti, C.L. Ogg and D. swern, J. Am. chem. soc.. 77, 4037 (1955). Spectra were recorded on a Hewlett Packard 8451 diode array spectrophotometer. The samples were scanned over the wavelength range 200 to 800 nm for one minute (spectra recorded every 6 sec). CMP is used below as abbreviation for peroxidase derived form Coprinus macrorhizua (obtained from Chemical Dynamics). H2O2 is used synonymously with hydrogen peroxide. 2,4-DCP and PCA are used as abbreviations of 2,4-dichlorophenol and p-coumaric acid. 13 -uobi± Example l. (Bleaching of Congo Red in solution) To a solution of Congo Red (0.058 mM, 42 mg/1 (dye content 93 %, giving an initial absorbance at 486 nm of 2.0) in phosphate buffer pH 7 (0.1 M) was added as bleaching agent either 2 mM 1 mM peroxyoctanoic acid, or 2.5 mg/1 CMP + 0.25 mM H202. The experiments were performed at 25 °C in 1 cm quartz calls containing 1 ml. As listed below, only the peroxidase system gave any bleaching effect (monitored as observed change in absorbance at 486 nm in one minute). Bleaching system Delta absorbance in 1 min 2 mM H202 0.00 1 mM Peroxyoctanoic acid 0.00 2.5 mg/1 CMP + 0.25 mM H202 0.18 Example 2. (Bleach acceleration by phenolic compounds) Experiments were performed according to example 1, except that the accelerating effect of adding various phenolic compounds as an additional substrata along with the peroxidase and H2O2 was examined. 2,4-dcf and pca were added at a level of only 5 jiM (0.82 mg/1 in both cases). Bleaching system Delta absorbance in 1 min 2.5 mg/1 CMP + 0.25 mM H202 0.18 2.5 mg/1 CMP + 0.25 mM H202 + 5 MM 2,4-DCP 0.74 2.5 mg/1 CMP + 0.25 mM H202 + 5 fiM PCA 0.28 Example 3. (Bleaching of Acid Blue 4 5 in solution) Experiments were performed according to example 1 only using a solution of Acid Blue 45 (0.058 mM, 68 mg/1 (dye content ca 40 %) , giving an initial absorbance at 594 nn of 1.0). Bleaching was measured as change in absorbance-a£k594 nmV ~ /'V V I 2 f ^A/J993£ 14 235671 Bleaching system Delta absorbance in 1 min 2 mM H2O2 0.00 1 mM Peroxyoctanoio acid 0.00 2.5 mg/1 CMP + 0.25 TOM H202 0.42 Example 4. (Bleach acceleration by phenolic compounds) Experiments were performed as described in example 2 except for using Acid Blue 45 as described in example 3. Bleaching system 2.5 mg/1 CMP + 0.25 mM H202 2.5 mg/1 CMP + 0.25 TOM H202 + 2.5 mg/1 CMP + 0.25 mM H202 + Delta absorbance in 1 min 0.42 5 fiM 2,4-DCP 0.69 5 MM PCA 0.98 Example 5. Solutions of Congo Red and Acid Blue 45 prepared, according to example 1 and 3, were treated with laccase (100 mg/1, crude enzyme preparation, derived from Mvcoliophtora therroo-phile. available from Novo Nordisk as a special preparation, SP 315. Further information is available upon request). The difference *in absorbance relative to a solution without enzyme added was measured after an incubation time of 16 hours. Bleaching agent Difference in absorbance after 16 hr. Congo Red (486 nm) Acid Blue 45 (594 nm) 0.1 g/1 laccase 0.29 0.09 15 235 6 7 1 (Dye adsorption to textiles) In order to demonstrate that the effects seen in the above such solutions, experiments were carried out in which clean cotton swatches were immersed in solutions of model textile dyea. In one such experiment, the clean swatches were immersed in 0.Q5B mM and 0.012 mM solutions, respectively, of the dye Acid Blue 45 in 50 mM phosphate buffer (pH 7.0, 25*C) and agitated for 60 min. The phosphate buffer was freshly pre- 2+ pared from water of a hardness equivalent to 1.6 mM Ca . The swatch load was approx. 11 g cotton cloth/1. Afterwards the swatches were rinsed in tap water and air-dried in the dark on a clean towel overnight. The the remission at 600 nm (absorption region for blue substances) was measured on a Datacolor Elrephometer 2000. The results of three treatments within the above prescriptions were as follows: solution experiments are reflected on textiles present in Remission at 600 nm (%\ Swatches retrieved Swatches retrieved from 0.058 mM Acid from 0.012 mM Acid Blue 45 solution Blue 45 solution l. Reference (buffer only) 60 80 2. 0.2 mM H202 3. H2O2 as in 2 58 79 + 20 mg/1 CMP 74 90 Higher remission numbers here correspond to less blue color. Thus, the dye deposition on the clean swatches is con- 16 235 87 siderably less in the solutions with peroxidase present. Example 7. (Dye adsorption to textiles) In another experiment, the procedure of example 6 was repeated in every detail, except that the dye in the solutions was Congo Red (at the same mH levels). Here, visual inspection of the resulting swatches unequivocally demonstrated the effect of the peroxidase: treatments 1 and 2 gave in-distinguishably and heavily red-colored swatches, whereas only a faint yellowish color was seen on the swatches from treatment 3. Example 8. (Dye adsorption to textiles) In this experiment, a particular type of test swatch was added for demonstrating dye adsorption effects. Each swatch consisted of 6 strips of textile, each 1.5 cm by 5 cm, sown together; the 6 textile brands were triacetate, bleached cotton, nylon, polyester, orlon, and viscose rayon. The model washing liquor was a phosphate buffer prepared as in example 6 with 0.6 g/1 linear alkylbenzenesulfonatB added as a surfactant. Two 7 cm by 7 cm clean cotton swatches and one of the above multiswatches (also clean) were immersed in 1 litre of'the washing liquor, with Congo Red added to a level of 0.012 mM, in each of two Terg-o-tometer beakers. In beaker 1, the bleaching system consisted of H202 at a level of 2 mM, in beaker 2, 20 mg of CMP was further added. A wash of 30 min at 40*C with 60 rotations/min was performed, after which the swatches were rinsed in tap water and dried as above (example 6). This time, Hunter color difference readings were obtained for the multiswatches as follows: 17 235671 Hunter color difference readings Beaker 1 Beaker 2 (only H202) (H202+CMP) Triacetate 7.5 2.0 Cotton Nylon 69.9 35.0 Polyester Orion Viscose 57.2 16.0 23.4 5.0 9.8 27.4 69.7 30.7 (A value of 0 here indicates no change in color from the clean swatch and increasing numbers correspond to a visual impression of deeper color.) Thus, the conclusion from example 6 is also valid here for all the textile brands studied. Example 9. (Dye transfer from textile to textile) Swatches dyed with Congo Red as a model dye for azo textile dyes was prepared by immersing clean cotton swatches in a bath of Congo Red and sodium sulfate in deminaralized water and keeping them there during a gradual heating to 90*C, ending with addition of further sodium sulfate and a period of a constant temperature of 90*C. After being dyed the swatches were rinsed in cold tap water and dried overnight between layers of gauze. In the present experiment, washing was carried out in three Terg-o-tometer beakers under the same general conditions as in example 8. The contents of the beakers were: 18 235671 Beaker 1: Only phosphate buffer with LAS (as in example 8) Beaker 2: Buffer + LAS + 2 mM H2c>2 Beaker 3: As 2 with 20 mg/1 CMP added In each beaker was introduced 2 Congo Red swatches, 7 cm by 7 cm, and one clean multiswatch (see example 8). After washing and drying as in example 8, the Hunter readings of the multiswatches were as follows: Beaker 1 Pfaker 2 Beaker 3 Triacetate 3.4 3.4 2.8 Cotton 45.7 45.3 36.6 Nylon 41.6 40.9 35.6 Polyester 7.9 7.4 6.7 Orion 14.7 15.0 11.2 Viscose 45.1 44.6 36.3 Thus, thB swatches in beaker 1 suffer a substantial dye transfer which is not remedied by hydrogen peroxide alonB, but reduced significantly by the peroxidase treatment. The red swatches from the three beakers had essentially identical readings, showing that the peroxidase treatment i does not change the dyeing any more than the other treatments . Example 10 (Dye adsorption to textiles) For the purpose of studying the peroxidase effeot in a more realistic washing environment, a powder detergent was composed as follows: 19 235 67 w/w * active material Sodium carbonate 22 Sodium diphosphate 17 Sodium silicate 7 Sodium triphosphate 5 sodium perborate monohydrate 4 Sodium nonanoyloxybenzenesulfonate 5 Sodium linear alkylbenzenesulfonate . 9 sodium alkyl sulfate 4 Various minor components: alcohol ethoxylate, diethylenetriamine pentaacetate, polyacrylats, . polyethylene glycol, protease, optical brightener each < 1 Sodium sulfate and other miscellaneous ...balance This detergent was used at a level of 2 g/1 in water of a 2+ hardness equivalent to 1.6 mM Ca to produce a washing liquor in which pH was adjusted to 8.5. In this washing liquor, Congo Red was dissolved to a level of 0.012 mM. Beaker 1 was the reference (detergent + Congo Red); in beaker 2, CMP was added to a level of 20 mg/1. In both beakers, two clean cotton swatches and one clean multiswatch were added as in example 8. All other conditions were as in example 8 and the Hunter data for the multiswatches after the wash were as follows: Beaker 1 Beaker 2 Triacetate 4.0 l.l Cotton 62.5 2.3 Nylon 48.0 l.l Polyester 4.0 0.4 Orion 18.4 1.2 Viscose 66.3 1.3 </div>

Claims

<div class="application article clearfix printTableText" id="claims"> 20 235671 Once again, the peroxidase clearly reduces - here almost eliminates - the amount of color deposited on the swatches. Example 11 (Dye transfer from textile to textile) In this final example, the detergent solution from example 9 was used in a Terg-o-tometer trial where two of the Congo Red-*dyed swatches described above (example 9) were washed together with one clean multiswatch in each of two beakers. Beaker 1 contained just 1 litre of detergent solution, beaker 2 additionally contained 20 mg/1 of CMP. The remaining conditions were as in example 8. The swatches, after retrieval from the washing liquor, rinsing and drying as above, showed the following Hunter color difference data: Triacetate 2.3 1.1 Cotton 47.0 13.1 Nylon 36.0 11.3 Polyester 2.1 l.l Orion 6.5 2.7 Viscose 48.7 10.6 A considerable transfer of dye was thus observed in beaker 1, and this was significantly reduced by adding the peroxidase to the washing liquor. Again, the dyed swatches were checked also, and no color difference was seen between the two treatments. 21 235671 WHAT WE CLAIM IS; 1 . A process for inhibiting the transfer of a textile dye from a dyed fabric to another fabric when said fabrics are washed and/or rinsed together in a wash liquor, the process comprising adding an enzyme exhibiting peroxidase activity or an enzyme exhibiting a suitable oxidase activity to the wash liquor in which said fabrics are washed and/or rinsed.
2. A process according to Claim 1, wherein one or more substrates for the enzyme are added at the beginning of or during the washing and/or rinsing process.
3. A process according to Claim 2, wherein, when the enzyme is a peroxidase, the substrate is hydrogen peroxide or a hydrogen peroxide precursor.
4. A process according to Claim 3, wherein the hydrogen peroxide precursor is a perborate or percarbonate.
5. A process according to Claim 3 or 4, wherein an enzymatic system capable of generating hydrogen peroxide is added at the beginning of or during the washing and/or rinsing process.
6. A process according to Claim 1, wherein the enzyme exhibiting oxidase activity is catechol oxidase (EC 1.10.3.1) or laccase (EC 1.10.3.2).
7. A process according to Claim 1, wherein the textile dye is a synthetic dye or a natural or nature-identical dye.
8. A process according to Claim 7, wherein the s^xifehetic dye is an azo dye. A* ! 'V t 2 IJUNI993S;! 22 23567
9. A process according to Claim 7, wherein the natural or nature-identical dye is indigo.
10. A process according to Claim 2, wherein an additional oxidisable substrate is added at the beginning of or during the washing and/or rinsing process.
11. A process according to Claim 10, wherein the oxidisable substrate is a metal ion, a halide ion or an organic compound.
12. A process according to Claim 11 , wherein the organic compound is a phenol.
13. A process according to Claim 12, wherein the phenol is p-hydroxycinnamic acid or 2,4-dichlorophenol.
14. A process according to any one of Claims 10 to 13, wherein the amount of the oxidisable substrate added is between substantially 1 plM and substantially 1 mM.
15. A process according to Claim 1 , wherein the enzyme is one producible by a microorganism.
16. A process according to Claim 15, wherein the microorganism is a bacterium or a fungus.
17. A process according to Claim 1, wherein the enzyme is of plant origin.
18. A process according to Claim 1 , wherein the enzyme is one producible by a method comprising cultivating a host cell transformed with a recombinant DNA vector carrying a DNA sequence encoding said enzyme as well as DNA sequences encoding functions permitting the expression of the enzyme, in a culture medium under conditions permitting, V'2 JJUNI992% JJ 23 235671 expression of the enzyme and recovering the enzyme from the culture.
19. A process according to any one of Claims 10 to 13, wherein the enzyme exhibiting peroxidase activity is a haloperoxidase.
20. A process according to Claim 19, wherein the haloperoxidase is a chloro or bromo peroxidase.
21 . A process according to Claim 1, wherein the enzyme is active at a pH of 6.5-10.5.
22. A process according to Claim 21, wherein the pH is 6.5-9.5.
23. A process according to Claim 21 or 22, wherein the pH is 7.5-9.5.
24. A process according to Claim 1, wherein the enzyme is added in an amount of 0.01-100 mg/1 of wash liquor.
25. A process according to Claim 1, wherein the enzyme is incorporated in a detergent composition.
26. A process according to Claim 25, wherein one or more substrates for the enzyme are also incorporated in the detergent composition.
27. A process for bleaching textile dyes in solution or dispersion, the process comprising adding an enzyme exhibiting peroxidase activity or an enzyme exhibiting a suitable oxidase activity to said solution or dispersion. o 671 24
28. A process according to Claim 27, wherein one or more substrates for the enzyme are also added to the solution or dispersion.
29. A process according to Claim 28, wherein, when the enzyme is a peroxidase, the substrate is hydrogen peroxide or a hydrogen peroxide precursor.
30. A process according to Claim 29, wherein the hydrogen peroxide precursor is a perborate or percarbonate.
31 . A process according to Claim 29 or 30, wherein an enzymatic system capable of generating hydrogen peroxide is added at the beginning of or during the bleaching process.
32. A process according to Claim 27, wherein the enzyme exhibiting oxidase activity is catechol oxidase (EC 1.10.3.1) or laccase (EC 1.10.3.2).
33. A process according to Claim 27, wherein the enzyme is active at a pH of 6.5-10.5.
34. A process according to Claim 33, wherein the pH is 6.5-9.5.
35. A process according to Claim 33 or 34, wherein the pH is 7.5-9.5.
36. A process according to Claim 27, wherein the textile dye is a synthetic dye or a natural or nature-identical dye.
37. A process according to Claim 36, wherein the synthetic dye is an azo dye. ~f(3.e&¥feWT0Wttc*- ■ 7 IftHW 25 235671
38. A process according to Claim 36, wherein the natural or nature-identical dye is indigo.
39. A process according to Claim 27, wherein an additional oxidisable substrate is added to said solution or dispersion.
40. A process according to Claim 39, wherein the oxidisable substrate is a metal ion, a halide ion or an organic compound.
41 . A process according to Claim 40, wherein the organic compound is a phenol.
42. A process according to Claim 41, wherein the phenol is p-hydroxycinnamic acid or 2,4-dichlorophenol.
43. A process according to any one of Claims 39 to 42, wherein the amount of oxidisable substrate added is between substantially 1 jaM and substantially 1 mM.
44. A bleaching agent for inhibiting the transfer of a textile dye from a dyed fabric to another fabric when said fabrics are washed and/or rinsed together in a wash liquor, the agent comprising an enzyme exhibiting peroxidase activity or an enzyme exhibiting a suitable oxidase activity.
45. A bleaching agent according to Claim 44, which further comprises one or more substrates for the enzyme.
46. A bleaching agent according to Claim 45, wherein, when the enzyme is a peroxidase, the substrate is hydrogen peroxide or a hydrogen peroxide precursor. 26 235671
47. A bleaching agent according to Claim 46, wherein the hydrogen peroxide precursor is a perborate or percarbonate.
48. A bleaching agent according to Claim 46 or 47, which additionally comprises an enzymatic system capable of generating hydrogen peroxide.
49. A bleaching agent according to Claim 44, wherein the enzyme exhibiting oxidase activity is catechol oxidase (EC 1.10.3.1) or laccase (EC 1.10.3.2).
50. A bleaching agent according to Claim 44, which additionally comprises an oxidisable substrate.
51. A bleaching agent according to Claim 50, wherein the oxidisable substrate is a metal ion, a halide ion or an organic compound.
52. A bleaching agent according to Claim 51, wherein the organic compound is a phenol.
53. A bleaching agent according to claim 52, wherein the phenol is p-hydroxycinnamic acid or 2,4-dichlorophenol.
54. A bleaching agent according to any one of Claims 50 to 53, wherein the amount of oxidisable substrate is between substantially 1 ]iM and substantially 1 mM.
55. A bleaching agent according to Claim 44, wherein the enzyme is one producible by a microorganism.
56. A bleaching agent according to Claim 55, wherein the microorganism is a bacterium, a fungus, an actinomycete or a basidiomycete. 5671
57. A bleaching agent according to Claim 44, wherein the enzyme is one producible by a method comprising cultivating a host cell transformed with a recombinant DNA vector carrying a DNA sequence encoding said enzyme as well as DNA sequences encoding functions permitting the expression of the enzyme, in a culture medium under conditions permitting the expression of the enzyme and recovering the enzyme from the culture.
58. A bleaching agent according to Claim 44, wherein the enzyme exhibiting peroxidase activity is a haloperoxidase.
59. A bleaching agent according to Claim 58, wherein the haloperoxidase is a chloro or bromo peroxidase.
60. A bleaching agent according to Claim 44, wherein the enzyme is active at a pH of 6.5-10.5.
61. A bleaching agent according to Claim 60, wherein the pH is 6.5-9.5.
62. A bleaching agent according to Claim 60 or 61, wherein the pH is 7.5-9.5.
63. A process according to any one of Claims 1 to 43, substantially as hereinbefore described with reference to any example thereof.
64. A bleaching agent according to any one of Claims 44 to 62, substantially as hereinbefore described with reference to any example thereof. OATED THIS DAY OF ^ A- iv//^RK & S pEix/A OlA/yuL ~- ./ < AGENTSTOR THE APPLICANTS 19 94- </div>