Enzyme blends for bio-scouring of cellulose fibers

Abstract

A composition for the purification of cellulose, and a process of using said composition in a bio-scouring step of said cellulose. The composition comprises an enzyme blend consisting of at least one pectinase and at least one glycosidase able to hydrolyze β-1,4-glycosidic bonds. Bio-scouring of cellulose using enzymes is less energy-intensive and more environmentally friendly than the traditional pre-treatment of cellulose using caustic soda.

Description

Enzyme Blends for Bio-Scouring of Cellulose FibersFIELD OF THE INVENTION

[0001] The invention relates to compositions for the textile industry, the compositions comprising different enzymes that are able to break down non- cellulosic impurities like pectins and hemicelluloses on cellulose fibers stemming from cotton, hemp, flax or other plants. The compositions may include pectinases, hemicellulases and cellulases, and are used during pre-treatment, in particular a bio-scouring step, of cellulose-comprising materials.BACKGROUND OF THE INVENTION

[0002] The textile industry contributes significantly to the economies of most developing nations. However, the industry has also remained one of the most polluting and energy-intensive industries.

[0003] Many textiles nowadays are made from cellulose or blends that, apart from cellulose, may contain fibers of synthetic origin such as polyester or polyurethane, and / or other natural fibers like wool or silk. Cellulose is harvested from the leafs, seeds and bast of plants. Cellulose from cotton for example is a seed fiber, while cellulose from hemp and flax are bast fibers. Cellulose fibers have different characteristics depending on their origin, as not only their molecular structure differs (mostly in terms of molecular weight), but also because the fibers are associated with various other materials, considered as impurities by the textile industry.

[0004] Due to their natural origin, cellulose fibers can be contaminated with various different compounds such as hemicelluloses, pectins, proteins, waxes, salts, and small inorganic or organic matter. Bast fibers often contain small amounts of lignin.

[0005] Other impurities are inadvertently added during processing of the fibers. Usually, fibers are spun into yarns or threads, which in turn are used to makefabrics and textiles by different techniques such as weaving, knitting, crocheting, braiding, felting and twisting.

[0006] In order to make the threads or yams smoother and more processable, they often are impregnated with sizing agents. Common sizing agents are for example starch, waxes and carboxymethyl cellulose. Machine oils can potentially contaminate the fibers, threads, yams, fabrics or textiles during manufacturing.

[0007] Before a cellulose-comprising material, for example a piece of clothing, can be sold to the consumer, it must undergo several stages of treatment. A so- called pre-treatment not only aims at the removal of the non-cellulosic impurities mentioned above, thereby rendering the cellulose clean and white, but also at increasing the hydrophilicity of the material, as good water-absorbency and water-retention are beneficial during further processing of the cellulose- comprising material.

[0008] Pre-treatment of a cellulose-comprising material can be divided into a singeing step, a desizing step, a scouring step, and a bleaching step. Singeing is the process of burning off protruding fibers from the surface of the material, thereby improving its lustre and smoothness. Protruding fibers, also called fuzz, are responsible for scattered reflection and hence contribute to a dull appearance. The desizing step is designed to remove the sizing agent, the absence of which is fundamental to an efficient scouring step. Scouring is designed to remove the vast majority of impurities such as oils, waxes, pectins, hemicelluloses and lignin, and bleaching is designed to remove any remaining residuals.

[0009] After pre-treatment, the smooth, clean, white and hydrophilic cellulose- comprising material can then be subjected to a dyeing step, which in turn is followed by a finishing step, where the colored material is treated with for example silicone in order to make it softer and smoother. Without thorough pretreatment of the cellulose-comprising material, neither dyeing nor finishing gives results of high quality.

[0010] Traditionally, desizing is achieved using dilute acids or enzymes. The current general scouring procedure consists in boiling the cellulose-comprising material in strong caustic soda (25-50 g NaOH per liter). The sodium hydroxide turns waxes and lipids into water-soluble products by saponification, therebyremoving these undesired impurities. Non-saponifiable oils are emulsified by added surfactants. Hemicelluloses and pectins are hydrolyzed and the reaction products dissolved under these strongly alkaline conditions. Large amounts of heat are needed to boil the water, and considerable amounts of hazardous waste waters are generated. The process is therefore associated with high energy consumption and a considerable use of chemicals, which makes it inefficient in terms of energy and resource conservation and thus reduces its overall environmental and economic efficiency.

[0011] Because of the drastic conditions applied during the scouring step, with temperatures reaching up to 98 °C for 45 min, the cellulose fibers themselves can be damaged by hydrolysis. Damaged cellulose fibers are characterized by reduced tensile and tear strengths, and are therefore unwanted for the manufacture of textiles.

[0012] An alternative scouring process which is less harmful to the cellulose fibers and the environment consists in the so-called bio-scouring, which removes undesired impurities through the use of enzymes that are able to degrade starch, pectins and / or hemicelluloses.

[0013] EP 1 194 631 B1 for examples disclosed a one-bath method for bioscouring of textiles using a pectinase, protease and / or lipase, with simultaneous or subsequent dyeing of said textiles in the same container.

[0014] EP 2 933373 B1 disclosed a bio-scouring method employing an amylase and a pectinase whose efficiency could be boosted by addition of a water- soluble polymer such as polyvinylpyrrolidone (PVP).

[0015] Various other treatment procedures of textiles using enzymes are disclosed in US 6261828, US 5749923, US 5711764, US 2002 / 115194 and JP H0967777.OBJECT OF THE INVENTION

[0016] It is an object of the present invention to provide a composition for the bio-scouring of cellulose-comprising materials that is able to remove a large array of contaminants potentially present in cellulose fibers harvested from plants and processed into threads, yarns, fabrics or textiles. These contaminants may comprise pectins, hemicelluloses and various sizing agents. The method of using said composition in a bio-scouring step of a cellulose-comprising material is a mild and environmentally friendly alternative to the traditional caustic soda process.SUMMARY OF THE INVENTION

[0017] The problem is solved by a composition for removing impurities from cellulose-comprising materials in a bio-scouring step, in which the cellulose- comprising material is brought into contact with a composition according to the invention ("composition") comprising an enzyme blend.

[0018] The composition for bio-scouring of a cellulose-comprising material comprises at least one pectinase and at least one glycosidase that is able to hydrolyze [3-1 ,4-glycosidic bonds.

[0019] The at least one glycosidase able to hydrolyze [3-1 ,4-glycosidic bonds can be selected from at least one hemicellulase, preferably a xylanase, at least one cellulase, or a mixture thereof.

[0020] The at least one glycosidase able to hydrolyze [3-1 ,4-glycosidic bonds can consist of a mixture of at least one hemicellulase, preferably a xylanase, and at least one cellulase.

[0021] The at least one pectinase can be present in a concentration between 0.15 % and 0.4 %, preferably between 0.18 % and 0.36 %, based on the total weight of the composition.

[0022] The at least one hemicellulase can be present in a concentration between 0.15 % and 0.4 %, preferably between 0.18 % and 0.36 %, based on the total weight of the composition.

[0023] The at least one cellulase can be present in a concentration between 0.02 % and 0.14 %, preferably between 0.03 % and 0.12 %, based on the total weight of the composition.

[0024] The at least one pectinase in the composition can be a pectate lyase.

[0025] The composition can further comprise at least one additive chosen from a sequestering agent, an ionic surfactant, a non-ionic surfactant, at least one desizing agent, for example an alpha-amylase, a microbiocide as preservative, sorbitol, a salt, preferably sodium chloride, or a combination thereof.

[0026] The composition can have a pH value between 4 and 7, or between 4 and 6, or between 4.5 and 5.5, preferably at 5. In a preferred embodiment of theinvention, the composition has a pH value below 7, in particular below 6.5. In a preferred embodiment of the invention, the composition has a pH value between 4 and below 7, or between 4 and 6.5, or between 4 and 6, or between 4 and 5.5, or between 4 and 5, or between 4.5 and 5. In a particularly preferred embodiment, the composition has a pH of 5. In a preferred embodiment of the invention, the composition does not have a pH value of 7 or greater. In a preferred embodiment of the invention, the composition does not have an alkaline pH value.

[0027] Further to the invention is a method for the preparation of a composition according to the invention. The method comprises mixing the at least one pectinase and the at least one glycosidase that is able to hydrolyze [3-1 ,4- glycosidic bonds, in water.

[0028] Further to the invention is a method for bio-scouring a cellulose- comprising material, comprising bringing into contact said cellulose-comprising material with a composition according to the invention. In a preferred embodiment of the invention, the cellulose-comprising material is a knitted or woven textile.

[0029] The method for bio-scouring a cellulose-comprising material can be performed at a temperature between 50°C and 98°C, or between 60°C and 98°C, or between 50°C and 90°C, or between 60°C and 90°C, or between 60°C and 80°C, or between 50°C and 80°C, or between 50°C and 70°C. In a preferred embodiment of the invention, the method for bio-scouring a cellulose- comprising material can be performed at a temperature between 60°C and 98°C, or between 65°C and 98°C, or between 70°C and 98°C, or between 75°C and 98°C, or between 80°C and 98°C, or between 85°C and 98°C, or between 90°C and 98°C. In a preferred embodiment of the invention, the method for bioscouring a cellulose-comprising material can be performed at a temperature between 50°C and 90°C, preferably between 60°C and 70°C.

[0030] The method for bio-scouring a cellulose-comprising material can be performed at a pH value in the range between 4 and 7, or between 4 and 6, or between 4.5 and 5.5, preferably at 5. In a preferred embodiment of the invention, the method for bio-scouring a cellulose-comprising material can be performed at a pH value below 7, in particular below 6.5. In a preferred embodiment of the invention, the method for bio-scouring a cellulose-comprising material can beperformed at a pH value between 4 and below 7, or between 4 and 6.5, or between 4 and 6, or between 4 and 5.5, or between 4 and 5, or between 4.5 and 5. In a particularly preferred embodiment, the method for bio-scouring a cellulose-comprising material can be performed at a pH of 5. In a preferred embodiment of the invention, the method for bio-scouring a cellulose- comprising material is not performed at an alkaline pH.

[0031] Further to the invention is the use of a composition according to the invention for bio-scouring of a cellulose-comprising material. The cellulose- comprising material may be a knitted or woven textile.

[0032] Further to the invention is a cellulose-comprising material that has been treated with a composition according to the invention.

[0033] Further to the invention is a cellulose-comprising material that is a textile.DETAILED DESCRIPTION OF THE INVENTION

[0034] The underlying technical problem is solved by an aqueous composition for bio-scouring of a cellulose-comprising material, the composition comprising at least one pectinase and at least one glycosidase that is able to hydrolyze [3- 1 ,4-glycosidic bonds.

[0035] The advantage of the composition according to the invention is that cellulose-comprising materials can be freed from impurities in a more eco- friendly way, that in addition does not damage the cellulose.

[0036] The term "bio-scouring" shall, within the context of the present invention, refer to a process that removes undesired impurities from a cellulose- comprising material through the use of enzymes. For example, pectin can be devoured by a pectinase. Said bio-scouring of cellulose is essentially a purification of cellulose, and involves the removal of non-cellulosic impurities.

[0037] The term “cellulose-comprising material” shall, within the context of the present invention, refer to any material that comprises or consists of cellulose, i.e., a fiber, thread, yarn, textile or fabric. Cellulose is a polymeric macromolecule that exclusively consists of D-glucose units linked in a linear fashion by [3-1 ,4-glycosidic bonds. A single cellulose molecule can consist of several hundred up to many thousands of D-glucose units. Many of such chains form a cellulose fiber, in which the polymeric molecules are held together byhydrogen bonds. Threads made of cellulose fibers can be combined with threads made of other materials during the weaving step, to obtain fabrics or textiles with optimized properties for specific applications. Cellulose can be combined in that way with for example artificially produced polyesters or polyurethanes, or other naturally occurring fibers such as wool or silk. Fabrics or textiles comprising or consisting of such blends shall be included in the term "cellulose-comprising materials" within the context of the present invention. Such blend materials can be subjected to the same pre-treatment steps as fabrics or textiles made from cellulose alone.

[0038] A cellulose-comprising material can further comprise cellulose from different sources, e.g., cotton and hemp. For the context of the present invention, the source of the cellulose does not matter.

[0039] Under the term "textile" within the context of the present application any piece of cloth or fabric, woven or unwoven, that was made of yams, threads or fibers is to be understood. All textiles referred to herein comprise cellulose to some degree.

[0040] The composition according to the invention comprises an “enzyme blend”. An enzyme blend is a mixture of different enzymes, said enzymes being at least one pectinase and at least one glycosidase able to hydrolyze [3-1 ,4- glycosidic bonds.

[0041] Under the term “pectinase” within the context of the present application, an enzyme is to be understood decomposing pectin. Pectin is an acidic heteropolysaccharide that is naturally accompanying cellulose harvested from plants like cotton, hemp or flax. Like cellulose, pectin forms a component of the cell walls of said plants, and is therefore closely associated with the cellulose. Pectin is mainly composed of D-galacturonic acid units that are linked via a-1 ,4- glycosidic bonds. However, pectin is not linear, but displays a multi-branched structure, with the side chains containing various other sugars such as rhamnose, arabinose, galactose and xylose. The D-galacturonic acid units can further be esterified to different degrees by methoxy-groups. There are different groups of pectinases, two of which are pectin lyases (EC 4.2.2.10) and pectate lyases (EC 4.2.2.2), both being able to directly cleave the a-1 ,4-glycosidic bonds of the pectin molecular skeleton by a [3-elimination mechanism withoutproducing highly toxic methanol. Other pectinases are pectin esterase, pectin hydrolase and propectinase.

[0042] Pectin lyases and pectate lyases are known as polymethylgalacturonic acid lyases and polygalacturonic acid lyases, respectively. The term pectinase shall be used throughout this application, and shall represent all currently known types of pectinases.

[0043] Preferably, a pectate lyase is used as pectinase. Pectate lyases are commercially available, for example under the trade name PrimaGreen® EcoScour from Genencor / DuPont, BioScour NPL from Piscean, Addscour LLP cone, from Advanced Enzymes, or 601 -L from Novozymes. Said commercial products generally constitute concentrated liquid formulations.

[0044] It is possible to combine two or more pectinases in one composition according to the invention. The pectinases combined in that way may be of different types, e.g., pectate lyase and pectin lyase, or of the same type.

[0045] The composition according to the invention also comprises at least one glycosidase able to hydrolyze [3-1 ,4-glycosidic bonds. Glycosidases (EC 3.2.1 ) are hydrolases with a wide spectrum of different substrates, whereby each glycosidase has its own specific substrate. Substrates are all possible oligo- or polysaccharides. A glycosidase cleaves the glycosidic bond between two saccharide units under consumption of a water molecule.

[0046] Preferably, the at least one glycosidase able to hydrolyze [3-1 ,4- glycosidic bonds, that is comprised in the composition, is selected from a hemicellulase or a cellulase, or a mixture thereof. The term “hemicellulase” shall, within the context of the present invention, refer to an enzyme that is able to depolymerize or degrade hemicellulose.

[0047] Hemicelluloses bind with pectin and cellulose to form the cross-linked network which serves as the matrix in the cell walls of plant cells. There are a number of differences between cellulose and hemicellulose. Whereas cellulose is relatively stable against hydrolysis, hemicelluloses are prone to hydrolysis in slightly alkaline or acidic aqueous media. While cellulose is made of relatively long, unbranched chains of only one single sugar type (D-glucose), hemicelluloses are short-chained, branched heteropolymers. Apart from mannose, galactose and arabinose, xylose is the most abundant saccharide in hemicelluloses. In general, the content of pentoses is much larger inhemicelluloses than the content of hexoses. Hemicelluloses that mostly contain D-xylose are also called xylanes. All saccharides in hemicelluloses are linked via (3-1 ,4-glycosidic bonds.

[0048] Sub-groups of hemicellulases are xylanases, a-D-glucuronidases, a-L- arabinofuranosidases, a-D-galactosidases, [3-xylosidases and p-mannanases, all having in common to attack glycosidic bonds of hemicellulose.

[0049] Preferably, the hemicellulase in the composition according to the invention is a xylanase, in particular an endo-1 ,4-[3-xylanase (EC 3.2.1.8). Xylanases represent a sub-group of pentosanases, and hydrolyze xylanes into oligosaccharides. Xylanases are commercially available, for example under the trade name Optimase CX200L, or iKnowzyme XL 300L (Reach Biotechnology, Thailand).

[0050] Cellulases are enzymes that are able to break cellulose chains, and consist of at least three major groups of enzymes, namely endo-1 ,4-|3- glucanases (EC 3.2.1.4), exoglucanases (EC 3.2.1.91 ), and [3-glucosidases (EC 3.2.1.21 ).

[0051] Preferably, the composition according to the invention comprises a cellulase. The cellulase has the effect of smoothening a textile through microdefibrillation. Microfibrillation is a phenomenon often occurring during wettreatment of textiles, in which microfibrils consisting of short cellulose fibers, that have been disassociated from the cellulose-pectin-hemicellulose matrix, move to the surface of the textile, thereby increasing the roughness of the textile surface. There they pose an obstacle for pectinases and xylanases to reach the cellulose-pectin-hemicellulose matrix, that is to be freed from pectins and hemicelluloses in the process according to the invention.

[0052] Cellulases are commercially available, for example under the trade name Primafast® GOLD RSL from Dupont or Novozyme, AB enzyme (by Research Biotechnology).

[0053] Preferably, the composition according to the invention comprises or consists of at least one pectinase, at least one hemicellulase and at least one cellulase. Most preferred is a composition that comprises or consists of a pectinase, a xylanase and a cellulase.

[0054] The at least one pectinase is comprised in the composition according to the invention in a concentration of at least 0.12 %, or at least 0.15 %, or at least0.18 %, or at least 0.2 %, or at most 0.42 %, or at most 0.4 %, or at most 0.36 %, or at most 0.32 %, based on the total weight of the composition. The at least one pectincase is present in the composition according to the invention in an amount between 0.12 % and 0.42 %, or between 0.15 % and 0.4 %, or between 0.18 % and 0.36 %, or between 0.2 % and 0.32 %, based on the total weight of the composition.

[0055] The at least one glycosidase able to hydrolyze [3-1 ,4-glycosidic bonds is comprised in the composition according to the invention in a concentration of at least 0.15 %, or at least 0.18 %, or at least 0.21 %, or at least 0.24 %, or at most 0.51 %, or at most 0.48 %, or at most 0.45 %, or at most 0.42 %, based on the total weight of the composition. The at least one glycosidase able to hydrolyze [3-1 ,4-glycosidic bonds is comprised in the composition according to the invention in a concentration between 0.15 % and 0.51 %, or between 0.18 % and 0.48 %, or between 0.21 % and 0.45 %, based on the total weight of the composition.

[0056] Preferably, the composition according to the invention comprises the at least one hemicellulase in a concentration of at least 0.12 %, or at least 0.15 %, or at least 0.18 %, or at least 0.2 %, or at most 0.42 %, or at most 0.4 %, or at most 0.36 %, or at most 0.32 %, based on the total weight of the composition. The at least one hemicellulase is present in the composition according to the invention in an amount between 0.12 % and 0.42 %, or between 0.15 % and 0.4 %, or between 0.18 % and 0.36 %, or between 0.2 % and 0.32 %, based on the total weight of the composition.

[0057] Preferably, the composition according to the invention comprises the at least one cellulase in a concentration of at least 0.02 %, or at least 0.03 %, or at least 0.04 %, or at most 0.14 %, or at most 0.13 %, or at most 0.12 %, based on the total weight of the composition. The at least one cellulase can be present in the composition according to the invention in an amount between 0.02 % and 0.14 %, or between 0.03 % and 0.13 %, or between 0.03 % and 0.12 %, or between 0.04 and 0.12 %, based on the total weight of the composition.

[0058] The composition according to the invention can further comprise sorbitol, which serves as a stabilizer for the enzymes. It can be present in a weight-based concentration from 20 wt% to 30 wt%, or from 22 wt% to 28 wt%, or from 24 wt% to 26 wt%, based on the total weight of the composition.

[0059] The composition according to the invention can further comprise a microbiocide as preservative that aims to prevent the growth of bacteria, yeasts and / or fungi in the composition. The microbiocide can be present in a concentration from 0.02 wt% to 0.06 wt %, or from 0.03 wt% to 0.05 wt%, or from 0.03 wt% to 0.04 wt%, based on the total weight of the composition. A preferred microbiocide is benzisothiazolinone. Microbiocidic formulations are commercially available, for example under the trade name Nipacide® BIT 20 from Clariant.

[0060] The composition according to the invention can further comprise a salt. A salt is necessary for the generation of a certain ionic strength in the solution typically needed by enzymes to work properly. Typically, the salt comprises or consists of an alkali or earth alkali halide. The salt can be present in a concentration from 2.0 wt% to 7.0 wt%, or from 2.5 wt% to 6.5 wt%, or from 3.0 wt% to 6.0 wt%, or from 3.0 wt% to 5.0 wt%, or from 3.0 wt% to 4.0 wt%, based on the total weight of the composition. In a preferred embodiment of the invention, the salt is sodium chloride.

[0061] The composition according to the invention can further comprise a desizing agent. Preferably, the desizing agent is an alpha-amylase, which is an enzyme that can degrade starch. Starch is a mixture of the two polymeric compounds amylose and amylopectin, which are both composed of D-glucose units connected via a-1 ,4-glycosidic bonds or a-1 ,6-glycosidic bonds. Alphaamylases are commercially available, for example under the trade name Bactosol® HPA liq. from Archroma, or Optisise® NEXT from Genencor / DuPont.

[0062] The composition according to the invention can further comprise a sequestering agent. Sequestering agents are organic compounds capable of linking metal ions or molecules together to form complex ring-like structures known as chelates. They combine with calcium, magnesium and other heavy metal ions to form molecules in which the ions are held so securely (sequestered) that they can no longer react. A sequestering agent in the composition of the invention helps to remove salt complexes that may be associated with the cellulose. Sequestering agent formulations are commercially available, for example under the tradename Lufibrol® ANTOX liq from Archroma, which is typically used in amounts of 1 to 4 mL per L of the composition.

[0063] The composition according to the invention can further comprise an emulsifier or surfactant. Possible are ionic and / or non-ionic surfactants. Formulations for emulsification and wetting are commercially available, for example under the trade name Kieralon® XTRA liq. cone, from Archroma. Typical concentrations of emulsifier or surfactant in the composition according to the invention are 3 to 8 mL per L of composition.

[0064] Most industrially used enzymes nowadays are prepared bio- technologically from microorganisms such as bacteria, fungi and yeasts. The pectinases and glycosidases used in the present invention can be wild-type enzymes, or mutated enzymes obtained from recombinant microorganisms. In addition, they can be chemically modified, either on the basis of the wild-type, or the mutated forms.

[0065] The composition according to the invention is an aqueous composition, preferably a solution i.e. , it comprises water.

[0066] The composition according to the invention has a pH value in the range between 4 and 7, or between 4 and 6, or between 4.5 and 5.5, preferably at 5. In a preferred embodiment of the invention, the composition has a pH value below 7, in particular below 6.5. In a preferred embodiment of the invention, the composition has a pH value between 4 and below 7, or between 4 and 6.5, or between 4 and 6, or between 4 and 5.5, or between 4 and 5, or between 4.5 and 5. In a particularly preferred embodiment, the composition has a pH of 5. In a preferred embodiment of the invention, the composition does not have a pH value of 7 or greater. The adjustment of the pH value is typically effected directly before the bio-scouring step is performed, and can be achieved by the addition of an acid, in particular an organic acid, such as for example acetic acid, citric acid or formic acid. The pH value of the composition is typically measured using a pH meter having a typical tolerance of ± 0.05 units.

[0067] Further according to the invention is a method for the preparation of a composition according to the invention. The method for the preparation of the composition of the invention comprises mixing the at least one pectinase and the at least one glycosidase that is able to hydrolyze |3-1 ,4-glycosidic bonds in water at room temperature. Optionally, other ingredients may be added to the composition, as described above.

[0068] Further according to the invention is a method for bio-scouring a cellulose-comprising material, wherein the method comprises bringing into contact the cellulose-comprising material with the composition according to the invention as defined above, or with a composition prepared by the method as defined above. The term “bringing into contact” within the context of the present invention encompasses all commonly known technical means to achieve a sufficient contact of the cellulose-comprising material with the composition according to the invention. Examples are dipping, soaking and spraying.

[0069] The claimed method for bio-scouring has the advantage to i.a. remove hemicelluloses and pectins through degradation of said polymeric structures, and thus enables a more efficient post-processing of the cellulose-comprising material. In case the composition according to the invention comprises a desizing agent, it is even possible to remove sizing agents like starch, and thus, to combine a desizing step and the scouring step.

[0070] After the method for bio-scouring according to the invention has been completed, the cellulose-comprising material can be subjected to a bleaching step, before it can be subjected to a dyeing step, and / or other finishing steps.

[0071] The method for bio-scouring according to the invention is also able to free a cellulose-comprising material from small matter like amino acids and salts through dissolution, as well as lipids, waxes and oils through emulsification.

[0072] The method for bio-scouring according to the invention provides advantages in subsequent processing steps, as the cellulose in the cellulose- comprising materials becomes more accessible to other chemicals. In general, the cellulose-comprising material becomes more hydrophilic and better wettable, which in turn means that less harsh conditions need to be applied in subsequent processing steps. During bleaching, less sodium hydroxide needs to be employed, and during dyeing, a more intense and even dyeing profile is achieved. Enzymatic reactions have obvious advantages such as mild reaction conditions and high specificity, compared with physical and chemical cleaning methods. The less harsh conditions therefore also bring along an improved retention of the molecular structure of the cellulose, i.e. , a cellulose fiber with good physical properties.

[0073] The temperature during the method of bio-scouring according to the invention can be between 50°C and 98°C, or between 60°C and 98°C, orbetween 50°C and 90°C, or between 60°C and 90°C, or between 60°C and 80°C, or between 50°C and 80°C, or between 50°C and 70°C. In a preferred embodiment of the invention, the temperature during the method of bio-scouring according to the invention can be between 60°C and 98°C, or between 65°C and 98°C, or between 70°C and 98°C, or between 75°C and 98°C, or between 80°C and 98°C, or between 85°C and 98°C, or between 90°C and 98°C. In general, each individual enzyme has its own optimal temperature, which is why the optimal temperature for an enzyme blend must necessarily be a compromise. If a high temperature for the method according to the invention is employed, an enzyme which has a lower optimum temperature, and which slowly decomposes at the chosen higher temperature, typically still shows some activity. In the process according to the invention, higher temperatures usually require shorter reaction times (contact times), but there is an upper limit to the temperature, as the degradation rates of the enzymes increase with temperature. A preferred range of the temperature for the bio-scouring process according to the invention is from 60°C to 70°C. In a preferred embodiment of the invention, the temperature for the bio-scouring process according to the invention is at least 60°C, in particular at least 65°C, in particular at least 70°C, in particular at least 75 °C, in particular at least 80°C, in particular at least 85°C. In a preferred embodiment of the invention, the temperature for the bio-scouring process according to the invention is at most 98°C.

[0074] The method for bio-scouring a cellulose-comprising material can be performed at a pH value in the range between 4 and 7, or between 4 and 6, or between 4.5 and 5.5, preferably at 5. In a preferred embodiment of the invention, the method for bio-scouring a cellulose-comprising material can be performed at a pH value below 7, in particular below 6.5. In a preferred embodiment of the invention, the method for bio-scouring a cellulose-comprising material can be performed at a pH value between 4 and below 7, or between 4 and 6.5, or between 4 and 6, or between 4 and 5.5, or between 4 and 5, or between 4.5 and 5. In a particularly preferred embodiment, the method for bio-scouring a cellulose-comprising material can be performed at a pH of 5. In a preferred embodiment of the invention, the method for bio-scouring a cellulose- comprising material is not performed at an alkaline pH. An advantage of bioscouring a cellulose-comprising material at a relatively acidic pH, in particular apH between 4 and below 7, is that bio-scouring can be carried out under mild conditions, in particular at a relatively low temperature and for a relatively short time, and results in lower quantities of waste water compared to scouring at alkaline pH, in particular compared to scouring using the traditional caustic soda process. This makes bio-scouring at a relatively acidic pH, in particular a pH between 4 and below 7, efficient in terms of energy and resource conservation and thus increases its overall environmental and economic efficiency. Furthermore, bio-scouring at a relatively acidic pH, in particular a pH between 4 and below 7, with the composition according to the invention results in an improved whiteness of the cellulose-comprising material, in particular cotton. Another advantage of bio-scouring a cellulose-comprising material at a relatively acidic pH, in particular a pH between 4 and below 7, is that the step of bio-scouring can be combined with other process steps in the pre-treatment of a cellulose-comprising material, in particular cotton, which are also carried out at a relatively acidic pH. As a result, the cellulose-comprising material can be directly used between those process steps, which is both resource-saving and time-efficient. This is particularly advantageous for knitted textiles, which are thus exposed to the process steps for a relatively short time, contributing to a particularly gentle treatment of these relatively tension-sensitive textiles.

[0075] After the cellulose-comprising material has been immersed in the composition of the invention for a specified time, usually between 15 and 45 min, preferably between 25 and 40 minutes, more preferably between 15 and 30 min, the cellulose-comprising material is removed and subjected to a rinsing step, e.g. by rinsing with water for several minutes. In a preferred embodiment of the invention, the cellulose-comprising material is rinsed twice with water of 60°C for 5 min, and then rinsed once with water of 40°C for 5 min, in order to remove the enzymes from the cellulose-comprising material.

[0076] The method of bio-scouring according to the invention can be conducted continuously, e.g. using the Pad Steam technology, semi-continuously, e.g. using the Cold Pad Batch technology, or batch-wise.

[0077] The method of bio-scouring according to the invention can be carried out in the following way:- provision of a composition according to the invention;- heating the composition according to the invention to a temperature as defined above;- contacting a cellulose-comprising material with the composition according to the invention for a time as defined above;- removing the cellulose-comprising material;- rinsing the cellulose-comprising material as defined above.

[0078] The thereby treated cellulose-comprising material has been purified to a certain degree, and therefore exhibits a lighter and whiter appearance. It is also characterized by a high hydrophilicity, i.e., high wettability, water-absorbency and water-retention ability.

[0079] Further according to the invention is the use of the composition according to the invention as defined above, or the composition prepared by the method according to the invention as defined above, for bio-scouring a cellulose- comprising material.

[0080] Further according to the invention is a cellulose-comprising material that has been treated with a composition according to the invention as defined above or with the composition prepared by the method according to the invention as defined above and / or by the method for bio-scouring according to the invention as defined above. The thus treated cellulose-comprising material has been purified to a certain degree, and therefore exhibits a lighter and whiter appearance. It is also characterized by a high hydrophilicity, i.e., high wettability, water-absorbency and water-retention ability.

[0081] The cellulose-comprising material is preferably a textile. The textile may be a knitted or woven textile. The above used definitions for these terms apply here as well.EXAMPLES

[0082] In the following examples, the invention is described in more detail without being limited thereto.

[0083] Used chemicals: PrimaGreen® EcoScour (pectate lyase) from IFF, Optimase CX200L (xylanase) from IFF, Primafast® GOLD HSL (cellulase) from Dupont, Nipacide® BIT 20 (preservative) from Clariant, Bactosol® HPA liq. (alpha-amylase) from Archroma, Kieralon® XTRA liq. cone, (wetting andemulsifying agent) from Archroma, Lufibrol® ANTOX liq. (sequestering agent) from Archroma, sorbitol, acetic acid, NaCI, water.

[0084] A basic composition A was prepared using the ingredients listed in Table 1. In this context, the term “basic composition” is understood as the composition used as basis for producing the application compositions and has nothing to do with “basic” in the sense of the pH.Table 1 . Ingredients of basic composition A (according to the invention).

[0085] Using basic composition A, application compositions 1 to 4 were prepared, wherein application compositions 1 to 3 are inventive, and application composition 4 is comparative (see Table 2).Table 2: Ingredients of application compositions 1 to 4 (unit: mL / L).

[0086] General application procedure: An application composition according to Table 2 was prepared, its pH value adjusted to 5 using acetic acid, and heated to 60°C. A woven fabric (100% raw cotton) was immersed in the application composition for 20 min, then removed, and rinsed twice with water of 60°C for 5 min, then rinsed once with water of 40°C for 5 min. The woven fabric treatedin this way was then subjected to the following tests to determine whiteness, water-absorptivity, residual sizing as well as residual pectin.

[0087] Test: Water-AbsorptivityWater-absorptivity was determined by the so-called “drop test”: A drop of colored water was placed on the surface of the cotton fabric, and the time in seconds was measured until the drop had been completely absorbed by the fabric.Table 3: Water-Absorptivity (drop test: seconds).In the drop test, lower values (in seconds) indicate higher hydrophilicity. As can be seen from the results, the untreated cotton fabric possess almost no waterabsorptivity.

[0088] Test: Residual PectinResidual pectin after the bio-scouring process can be determined qualitatively by dyeing the cotton samples with Ruthenium Red, a dyestuff that associates preferentially with pectin. Here, the 4 test samples, together with an untreated sample, have been dyed with Ruthenium Red. The more pale the red color after the dyeing process, the less pectin remained on the cotton fibers after the bioscouring process, and, consequently, the more efficient the bio-scouring process. Cotton strips of all 5 samples were dyed in an aqueous solution of Ruthenium Red for 30 min at 50°C, then thoroughly rinsed with water. Drying took place for at least 4 hours in the dark in an oven below 50°C. The color strength of the cotton strips was subsequently evaluated using a spectrophotometer (650) in the visible range of the spectrum (400 to 700 nm).Table 4: Residual pectin.It becomes obvious that the untreated sample contained the most pectin. In the case of sample 4, which was not bio-scoured, a somewhat lower amount of pectin was observed, while inventive samples 1 to 3 possessed the lowest amount of residual pectin in their structures.

[0089] Test: pH-specific effect on whitenessWhiteness was determined by the standard procedure of the International Commission on Illumination (CIE) on colorimetry. The CIE Whiteness value is derived from measurements of the light reflected by woven cotton fibers across the whole visible light spectrum.Application compositions 1 to 4 were provided as indicated in above Table 2. After the application compositions were prepared, the pH value of the application compositions was adjusted to either 5 using acetic acid, or 7 or 8 using 10% NaOH, respectively, and heated to 60°C. A woven fabric (100% raw cotton) was immersed in the application composition for 20 min, then removed, and rinsed twice with water of 60°C for 5 min, then rinsed once with water of 40°C for 5 min. The woven fabric treated this way was then subjected to the CIE whiteness test:In the CIE whiteness test, a higher CIE whiteness value corresponds to a brighter and whiter appearance of the fabric. As can be seen from the results, the effect of bio-scouring on the CIE whiteness value is pH-dependent. In particular, bio-scouring at a relatively acidic pH (pH = 5.0) with application compositions comprising basic composition A (application compositions 1 to 3)resulted in an improved whiteness. At the same time, scouring at increasing pH resulted in a decreased whiteness. Surprisingly, bio-scouring performed at pH 7.0 or pH 8.0 (application compositions 1 to 3 comprising basic composition A) resulted in worse whiteness values compared to application composition 4 lacking basic composition A. This suggests that bio-scouring with the composition comprising the ingredients of above Table 1 is pH dependent with the enzymes listed in Table 1 having their pH optimum at a pH below 7 and thus at a relatively acidic pH.

Claims

CLAIMS1 . An aqueous composition for bio-scouring of a cellulose-comprising material, the composition comprising at least one pectinase and at least one glycosidase that is able to hydrolyze (3-1 ,4-glycosidic bonds.

2. A composition according to claim 1 , wherein the at least one glycosidase able to hydrolyze [3-1 ,4-glycosidic bonds is selected from at least one hemicellulase, preferably a xylanase, at least one cellulase, or a mixture thereof.

3. A composition according to claim 1 or 2, wherein the at least one glycosidase able to hydrolyze [3-1 ,4-glycosidic bonds consists of a mixture of at least one hemicellulase, preferably a xylanase, and at least one cellulase.

4. A composition according to at least one of claims 1 to 3, wherein the at least one pectinase is present in a concentration between 0.15 % and 0.4 %, preferably between 0.18 % and 0.36 %, based on the total weight of the composition; and / or wherein the at least one hemicellulase is present in a concentration between 0.15 % and 0.4 %, preferably between 0.18 % and 0.36 %, based on the total weight of the composition; and / or wherein the at least one cellulase is present in a concentration between 0.02 % and 0.14 %, preferably between 0.03 % and 0.12 %, based on the total weight of the composition.

5. A composition according to at least one of the claims 1 to 4, wherein the at least one pectinase is a pectate lyase.

6. A composition according to at least of the claims 1 to 5, wherein the composition further comprises at least one additive chosen from a sequestering agent, an ionic surfactant, a non-ionic surfactant, a microbiocide as preservative, a salt, preferably sodium chloride, or a combination thereof.

7. A composition according to at least one of the claims 1 to 6, wherein the composition further comprises sorbitol.

8. A composition according to at least one of the claims 1 to 7, wherein the composition further comprises at least one desizing agent, for example an alphaamylase.

9. A composition according to at least one of the claims 1 to 8, wherein the composition has a pH of between 4 and 6.5, or between 4 and 6, or between 4.5 and 5.5, preferably at 5.

10. A method for the preparation of a composition according to at least one of the claims 1 to 9, wherein the method comprises mixing the at least one pectinase and the at least one glycosidase that is able to hydrolyze (3-1 ,4-glycosidic bonds, in water.11 . A method for bio-scouring a cellulose-comprising material, the method comprising bringing into contact said cellulose-comprising material with a composition according to at least one of the claims 1 to 9, or with a composition prepared according to claim 10.

12. A method according to claim 11 , wherein the temperature is between 50°C and 90°C, preferably between 60°C and 70°C.

13. Use of a composition according to at least one of the claims 1 to 9, or prepared according to claim 10, for bio-scouring of a cellulose-comprising material, preferably wherein the cellulose-comprising material is a knitted or woven textile.

14. A cellulose-comprising material that has been treated with a composition according to at least one of the claims 1 to 9, or with a composition prepared according to claim 10, or by the method according to at least one of the claims 11 and 12.

15. A cellulose-comprising material according to claim 14, wherein the cellulose- comprising material is a textile.

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