The present invention relates to methods for the enzymatic colour modification of dyed cellulosic textile fibre material, in particular denim dyed with indigo or sulphide dyes.
Some textile materials are washed after dyeing with the objective of adjusting the colour tone or shade on the dyed textile, also known as washdown effect. For instance, blue jeans made from indigo-dyed denim can be washed in the presence of pumice stones and enzymatic desizing agents, followed by an on tone-washdown process to obtain a desired worn appearance.
Conventional washdown processes comprise treatment of the coloured denim with sodium hypochlorite, what is unwanted in view of the appearance of fibre damages and because of ecological reasons.
Washdown with hydrogen peroxide is an alternative solution. The adjusting effect obtainable with hydrogen peroxide, however, is rather limited. Furthermore, the required high pH is ecologically undesirable.
An enzymatic washdown process which does not show the above indicated disadvantages would be desirable.
There is a need for an effective enzymatic washdown process for coloured cotton textiles which provides the desired wash-out effect under mild conditions and minimizes the adverse environmental impact, when compared to conventional textile colour modification processes.
The present invention accordingly relates to a method for adjusting the colour tone of dyed cellulosic textile fibre material comprising contacting said textile material with an enzymatic textile treatment composition comprising
(i) a perhydrolase enzyme,
(ii) an ester substrate for said perhydrolase enzyme, and
(iii) a hydrogen peroxide source.
The enzymatic treatment step of the present invention will employ, unless otherwise indicated, conventional techniques of molecular biology (including recombinant techniques), microbiology, cell biology, and biochemistry, which are within the skill of the art. Such techniques are explained fully in the literature, for example, Molecular Cloning: A Laboratory Manual, 2nd ed., (Sambrook et al., 1989); Oligonucleotide Synthesis (M. J. Gait, ed., 1984); Current Protocols in Molecular Biology (F. M. Ausubel et al, eds., 1994); PCR: The Polymerase Chain Reaction (Mullis et al., eds., 1994); and Gene Transfer and Expression: A Laboratory Manual (Kriegler, 1990).
Unless defined otherwise herein, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
Singleton, et al., Dictionary of Microbiology and Molecular Biology, 2nd ed., John Wiley and Sons, New York (1994), and Hale & Markham, The Harper Collins Dictionary of Biology, Harper Perennial, New York (1991) provide one of skill in the art with a general dictionary of many of the biotechnology related terms used in this invention. Any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention.
Numeric ranges provided herein are inclusive of the numbers defining the range. Unless otherwise indicated, nucleic acids are written left to right in 5′ to 3′ orientation; amino acid sequences are written left to right in amino to carboxy orientation, respectively.
The term “adjusting” as used herein, means the process of treating a textile material for a sufficient length of time and under appropriate pH and temperature conditions to produce a lighter colour in said textile material by removal, modification or masking of color-causing compounds in the textile material. Thus, “adjusting” refers to the treatment of a textile material to effect a brightening of the textile material.
The term “cellulosic textile fibre material” comprises natural cellulosic fibres such as cotton, linen and hemp, semi-synthetic cellulosic fibres such as viscose and lyocell as well as blends of cellulosic fibres and synthetic fibres such as elastane.
The method according to the invention is particularly suitable for the treatment of denim dyed with vat dyes, reactive dyes, direct dyes and sulphur dyes, most preferably for indigo-dyed denim.
Suitable substrates that can be treated with the method according to the invention are yarns, wovens, knits and garments.
The method according to the invention provides textile material distinguishing by soft handle and very good crease recovery properties.
A “perhydrolase” refers to an enzyme that is capable of catalyzing a perhydrolysis reaction that results in the production of a sufficiently high amount of peracid suitable for use in an enzymatic textile adjusting composition according to the method described herein. Generally, a perhydrolase enzyme used in the methods described herein exhibits a high perhydrolysis to hydrolysis ratio. In some embodiments, the perhydrolase comprises, consists of, or consists essentially of the Mycobacterium smegmatis perhydrolase amino acid sequence set forth in SEQ ID NO:1, or a variant or homolog thereof. In some embodiments, the perhydrolase enzyme comprises acyl transferase activity and catalyzes an aqueous acyl transfer reaction.
A “peracid” is an organic acid of the formula RC(═O)OOH, wherein R is an aliphatic, aromatic or araliphatic radical.
An “ester substrate” in reference to an enzymatic textile adjusting composition according to the invention described herein refers to a perhydrolase substrate that contains an ester linkage. Esters comprising aliphatic and/or aromatic carboxylic acids and alcohols may be utilized as substrates with perhydrolase enzymes. In some embodiments, the ester source is selected from the esters of one or more of the following acids: formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, nonanoic acid, decanoic acid, dodecanoic acid, myristic acid, palmitic acid, stearic acid, and oleic acid. In some embodiments, the ester source is an acetate ester. In some embodiments, the ester source is selected from one or more of propylene glycol diacetate, ethylene glycol diacetate, glycerol triacetate, ethyl acetate, and glycerol tributyrate.
The term “perhydrolyzation” or “perhydrolyze” or “perhydrolysis” as used herein refer to a reaction wherein a peracid is generated from an ester substrate and a hydrogen peroxide source. The perhydrolyzation reaction is catalyzed with a perhydrolase, e.g., acyl transferase or aryl esterase, enzyme. In some embodiments, a peracid is produced by perhydrolysis of an ester substrate of the formula RC(═O)OR*, where R and R* are the same or different organic moieties, in the presence of hydrogen peroxide (H2O2). In one embodiment, —OR* is —OH. In one embodiment, —OR* is replaced by —NH2. In some embodiments, a peracid is produced by perhydrolysis of a carboxylic acid or amide substrate.
The term “peracid,” as used herein, refers to a molecule derived from a carboxylic acid ester which has been reacted with hydrogen peroxide to form a highly reactive product that is able to transfer one of its oxygen atoms. It is this ability to transfer oxygen atoms that enables a peracid, for example, peracetic acid, to function as a brightening agent.
The phrase “perhydrolysis to hydrolysis ratio” refers to the ratio of the amount of enzymatically produced peracid to the amount of enzymatically produced acid by a perhydrolase enzyme from an ester substrate under defined conditions and within a defined time. In some embodiments, the assays provided in WO 05/056782 are used to determine the amounts of peracid and acid produced by the enzyme.
As used herein, “effective amount of perhydrolase enzyme” refers to the quantity of perhydrolase enzyme necessary to achieve the enzymatic activity required in the processes or methods described herein. Such effective amounts are readily ascertained by one of ordinary skill in the art and are based on many factors, such as the particular enzyme variant used, the pH used, the temperature used and the like, as well as the results desired (e.g., level of brightening).
As used herein, the term “transferase” refers to an enzyme that catalyzes the transfer of a functional group from one substrate to another substrate. For example, an acyl transferase may transfer an acyl group from an ester substrate to a hydrogen peroxide substrate to form a peracid.
As used herein, the term “acyl” refers to an organic group with the general formula RCO—, derived from an organic acid by removal of the —OH group. Typically, acyl group names end with the suffix “-oyl,” e.g., ethanoyl chloride, CH3CO—Cl, is the acyl chloride formed from ethanoic acid, CH3CO—OH.
As used herein, the term “acylation” refers to a chemical transformation in which one of the substituents of a molecule is substituted by an acyl group, or the process of introduction of an acyl group into a molecule.
As used herein, “oxidizing chemical” refers to a chemical that has the capability of brightening a textile. The oxidizing chemical is present at an amount, pH and temperature suitable for brightening. The term includes, but is not limited to hydrogen peroxide and peracids.
As used herein, the terms “purified” and “isolated” refer to the removal of contaminants from a sample and/or to a material (e.g., a protein, nucleic acid, cell, etc.) that is removed from at least one component with which it is naturally associated. For example, these terms may refer to a material which is substantially or essentially free from components which normally accompany it as found in its native state, such as, for example, an intact biological system.
As used herein, the term “polynucleotide” refers to a polymeric form of nucleotides of any length and any three-dimensional structure and single- or multi-stranded (e.g., single-stranded, double-stranded, triple-helical, etc.), which contain deoxyribonucleotides, ribonucleotides, and/or analogs or modified forms of deoxyribonucleotides or ribonucleotides, including modified nucleotides or bases or their analogs. Because the genetic code is degenerate, more than one codon may be used to encode a particular amino acid, and the polynucleotides applied applied within the context of the present invention encode a particular amino acid sequence. Any type of modified nucleotide or nucleotide analog may be used, so long as the polynucleotide retains the desired functionality under conditions of use, including modifications that increase nuclease resistance (e.g., deoxy, 2′-O-Me, phosphorothioates, etc.). Labels may also be incorporated for purposes of detection or capture, for example, radioactive or nonradioactive labels or anchors, e.g., biotin. The term polynucleotide also includes peptide nucleic acids (PNA). Polynucleotides may be naturally occurring or non-naturally occurring. The terms “polynucleotide” and “nucleic acid” and “oligonucleotide” are used herein interchangeably. Polynucleotides of the invention may contain RNA, DNA, or both, and/or modified forms and/or analogs thereof. A sequence of nucleotides may be interrupted by non-nucleotide components. One or more phosphodiester linkages may be replaced by alternative linking groups. These alternative linking groups include, but are not limited to, embodiments wherein phosphate is replaced by P(O)S (“thioate”), P(S)S (“dithioate”), (O)NR2 (“amidate”), P(O)R, P(O)OR′, CO or CH2 (“formacetal”), in which each R or R′ is independently H or substituted or unsubstituted alkyl (C1-C20) optionally containing an ether (—O—) linkage, aryl, alkenyl, cycloalkyl, cycloalkenyl or araldyl. Not all linkages in a polynucleotide need be identical. Polynucleotides may be linear or circular or comprise a combination of linear and circular portions. Suitable polynucleotides are described in WO 2005/056782.
As used herein, “polypeptide” refers to any composition comprised of amino acids and recognized as a protein by those of skill in the art. The conventional one-letter or three-letter code for amino acid residues is used herein. The terms “polypeptide” and “protein” are used interchangeably herein to refer to polymers of amino acids of any length. The polymer may be linear or branched, it may comprise modified amino acids, and it may be interrupted by non-amino acids. The terms also encompass an amino acid polymer that has been modified naturally or by intervention; for example, disulfide bond formation, glycosylation, lipidation, acetylation, phosphorylation, or any other manipulation or modification, such as conjugation with a labeling component. Also included within the definition are, for example, polypeptides containing one or more analogs of an amino acid (including, for example, unnatural amino acids, etc.), as well as other modifications known in the art.
The terms “analogous sequence”, “homologous protein”, “wild-type or native proteins”, “wild-type sequence”, “native sequence”, “naturally-occurring sequence”, “wild-type gene”, “related proteins”, “derivative proteins” and “variant proteins”, as used herein are familiar to those skilled in the art and are described in more detail in WO 2005/056782 on pages 12, 13 and 50 to 52, which are herein incorporated by reference. In some embodiments, homologous proteins are engineered to produce enzymes with desired activity(ies).
Several methods are known in the art that are suitable for generating variants of the enzymes described herein, including but not limited to site-saturation mutagenesis, scanning mutagenesis, insertional mutagenesis, random mutagenesis, site-directed mutagenesis, and directed-evolution, as well as various other recombinatorial approaches.