ENZYMATIC BLEACHING DETERGENT BASED ON IN SITU GENERATION OF PEROXYACIDS AND USE OF SUCH DETERGENT

Abstract: The detergent comprises an amidase, an amide and a hydrogen peroxide source. The peroxyacid formed in situ in the washing solution exhibits a superior bleaching effect and the amidase-amide system is a favorable alternative in comparison to prior art systems.

Description: ENZYMATIC BLEACHING DETERGENT BASED ON IN SITU GENERATION OF PEROXYACIDS AND USE OF SUCH DETERGENT The invention comprises an enzymatic bleaching detergent based on jln situ generation of peroxyacids, com- prising a hydrolase, a substrate therefore and a hydrogen peroxide source, and a use of such detergent. The above indicated in situ generation of peroxyacids refers to the in situ generation of peroxyacids in the washing solution. In the prior art the in situ generation of peroxy- acids in a detergent by means of a hydrolase is described, viz. in EP 0 253 487 and DOS 2 240 605. The peroxyacids are stronger oxidizing agents than the hydrogen peroxide source, i.e. hydrogen peroxide itself or hydrogen peroxide pre¬ cursors. Peroxyacids are better suited for bleaching purposes than the hydrogen peroxide source; they are generated in situ in the washing solution by means of a peroxyacid precursor, preferably an ester derivative of an organic carboxylic acid, and a hydrogen peroxide precursor, preferably sodium per¬ borate. From the above cited two patent documents it appears that an enzymatic bleaching detergent based on in situ generation of peroxyacids is described, where the hydrolase is a lipase or an esterase, and where the substrate therefore are precisely defined esters, including glycerides, ethylene glycol derivatives and propylene glycol derivates. An alternative detergent is needed, in the first place because alternative problem solutions are always wanted, and in the second place because introduction of the glycerides in the washing solution is unwanted in the sense that glycerides often are already present as fat soilings on the laundry, and because the glycerides have a very small water solubility and thus require an added emulsifier. Reference can be made to EP 0 253 487 A2, page 5, lines 19- 25. The enzymatic bleaching detergent according to the invention based on .in situ generation of peroxyacids in a detergent comprising a hydrolase, a substrate therefore and a hydrogen peroxide source is characterized by the fact that the hydrolase is an amidase, and that the substrate therefore is an amide. The amides are generally more easily solubilized in a washing solution than glycerides and thus do not require the addition of emulsifiers, or they require the addition of an emulsifier to a lesser extent. Thus, the system amide- amidase performs as good as or better than prior art systems ester-esterase. The amidase can be any amidase; however, amidases produced microbially are preferred. Practically any micro- bially produced enzyme preparation contains an amidase. The amide can be any amide, provided that it can be solubilized in the washing solution and is a substrate for the chosen amidase. In a preferred embodiment of the detergent accord¬ ing to the invention the detergent is made available in a particulate form, preferably as a non dusting granulate. In this manner stabilization problems which occur in liquid detergents, are not present, and consumer requirements in regard to dust level are fully met. In a preferred embodiment of the detergent accord¬ ing to the invention the hydrogen peroxide source is a perborate or a percarbonate, preferably a sodium perborate or a sodium percarbonate. These peroxide sources are the most common in commerce, and the cheapest, too, and they are fully satisfactory for the detergent according to the invention. In a preferred embodiment of the detergent accord¬ ing to the invention the amidase is produced microbially. Microorganisms are satisfactory amidase producers. In a preferred embodiment of the detergent accord¬ ing to the invention the amidase is produced by means of a bacterium, preferably belonging to the genus Pseudomonas, the Coryneform group of bacteria, and the order Actinomycetales. including the genus Rhodococcus. These are good amidase producers. In a preferred embodiment of the detergent accord¬ ing to the invention the microorganism is CBS 498.74. We have performed satisfactory washing trials on the basis of this microorganism. In a preferred embodiment of the detergent accord¬ ing to the invention the amidase is produced by means of a yeast, preferably belonging to the genus Candida. These are good amidase producers. In a preferred embodiment of the detergent accord¬ ing to the invention the amidase is produced by means of a fungus, preferably belonging to the genera Asperσillus or Fusarium. These are good amidase producers. In a preferred embodiment of the detergent accord¬ ing to the invention the amide is a carboxylic acid amide, preferably a carboxylic acid amide with 3-12 carbon atoms, more preferably a fatty acid amide or a dicarboxylic acid diamide. These amides are satisfactory precursors for the peroxyacids formed in situ in the washing solution. Formic amide and acetic amide are not well suited for the invention because of their toxicity. In a preferred embodiment of the detergent accord- ing to the invention the amide is a partial hydrolysis product of TAED (tetraacetyl ethylene diamine) , e.g. DAED (diacetyl ethylene diamine) . TAED is present in many per¬ borate containing detergents, as it is the most commonly used perborate activator. In a preferred embodiment of the detergent accord¬ ing to the invention the amide is present in an amount between 0.1 and 5 moles of amide per kg of the total deter¬ gent. With an amount of amide below 0.1 moles per kg of total detergent no significant bleaching effect is obtained, and with an amount of amide above 5 moles per kg of total detergent no significant increase of the bleaching effect is obtained. In a preferred embodiment of the detergent accord¬ ing to the invention the detergent also contains a lipase and/or a protease and/or an amylase and/or a cellulase. In this manner several other favorable washing effects can be obtained besides the bleaching effect. Also the invention comprises a use of the detergent according to the invention, wherein the detergent is used for bleaching of laundry in a washing solution with a temperature of between 10 and 60"C, a pH of 7.5-11, with a concentration of the detergent of between 1 and 10 g/1. Usually the washing process is carried out for at least 10 minutes, preferably for at least 20 minutes. In a preferred embodiment of the use according to the invention the temperature is between 25 and 55°C, the pH is between 9 and 10, the concentration of the detergent is between 2 and 5 g/1. These are the optimal conditions for obtaining a satisfactory bleaching effect. In a preferred embodiment of the use according to the invention the use is performed as a main wash. The environment in the washing solution during the main wash is favorable for the development of the bleaching effect. In a preferred embodiment of the use according to the invention the use is performed as a soaking process. The environment in the soaking solution during the soaking process is favorable for the development of the bleaching ef ect. The invention will be illustrated by the following examples. EXAMP-GE 1 In this example an amidase preparation was used which can be produced by conventional fermentation by means of the deposited microorganism CBS 498.74 (NCIB 12072) Brevibacterium strain B222. The activity of the amidase preparation was assayed by monitoring ammonia release (colorimetrically, using an alkaline phenol/sodium nitroprusside/hypochlorite reagent developing a colour at 640 nm) in a 0.1 M phosphate buffer at pH = 7.0 and room temperature, the substrate being propion- amide at 0.1 M. One amidase unit corresponds to conversion of 1 μmole of amide in 1 minute. In a Terg-O-Tometer washing trial, the effect of this amidase preparation on perborate bleaching was investi¬ gated. The Terg-O-Tometer test washing machine is described in J. C. Harris, Detergency evaluation and testing, Inter- science Publishers Ltd., 1954, page 60 - 61. The test swatches were cotton homogenously soiled with red wine, unsweetened blackcurrant juice, and tea. After soiling the swatches were air dried overnight, and then kept in the dark at 5°C. The washing solution was based on a buffer with sodium sulphate (15 mM) , triphosphate (4 mM) , silicate (2 mM) , and ethylenediaminetetraacetate (1.2 mM) . Furthermore, the washing solution contained 10 mM propionic amide and 1 mM hydroxylamine. Hydroxylamine was added because it acts as an inhibitor for catalase, which may be present in the amidase preparation. The water used has a hardness equivalent to 1.6 mM Ca As a hydrogen peroxide source NaB0 3 .4H 0 was used in a concentration of 12.6 mM. The pH of the washing solution was 9.3, the ratio between test swatches and washing solution was 12 g/1, the temperature was 50°C and the duration of the washing treat¬ ment was 60 minutes. Evaluation of bleaching effect: The washed swatches were rinsed in tap water, then dried overnight in the dark, and subsequently remission was measured on a Datacolor Elrephometer 2000. Fig. 1 shows detergency values at 460 nm, calcu- lated from remission values (R) by means of the following formula R (soiled, ashed) - R (soiled,not washed) detergency(%) = x 100 R (clean,not washed) - R (soiled,not washed) The data in Fig. 1 represents averages for two per¬ formances. Standard deviations are considerably lower than the detergency differences. On Fig. 1 the zero level for amidase activity corrresponds to amide and perborate, with no amidase added. As illustrated in Fig. 1, the bleaching effect of perborate is enhanced by adding the amide amidase system used in the detergent according to the invention. In addition. Fig. 1 shows that the effect increases with an increasing enzyme content (in Units/1) . EXAMPLE 2 In another washing trial, the effect of the amidase preparation of Example 1 on the perborate/TAED system was in¬ vestigated. The temperature was 40°C, the pH in the washing liquor was 8.5, the EDTA concentration was 0.03 mM, and the TAED concentration was 1.6 mM. No propionamide was present. The rest of the conditions were as in Example 1. Detergency at 460 nm Perborate+TAED Perborate+TAED+amidase 1) Red wine swatches 76 * 8% 78.9% Tea swatches 85.8% 87.1% 1) Amidase doses of 10 units/1 (red wine swatches) , 20 units/1 (tea swatches) . Standard deviations on the above detergency figures range around 0.5%.

Claims: CLAIMS 1. Enzymatic bleaching detergent based on .in situ genera¬ tion of peroxyacids comprising a hydrolase, a substrate therefore and a hydrogen peroxide source, wherein the hydro- lase is an amidase and the substrate therefore is an amide. 2. Detergent according to Claim 1, wherein the detergent is made available in a particulate form, preferably as a non dusting granulate. 3. Detergent according to Claim 1 or 2, wherein the hydrogen peroxide source is a perborate or a percarbonate, preferably a sodium perborate or a sodium percarbonate. 4. Detergent according to Claims 1 - 3, wherein the amidase is produced microbially. 5. Detergent according to Claim 4, wherein the amidase is produced by means of a bacterium, preferably belonging to the genus Pseudomonas, the Corvneform group of bacteria, and the order Actinomycetales. including the genus Rhodococcus. 6. Detergent according to Claim 5, wherein the micro¬ organism is CBS 498.74. 7. Detergent according to Claim 4, wherein the amidase is produced by means of a yeast, preferably belonging to the genus Candida. 8. Detergent according to Claim 4, wherein the amidase is produced by means of a fungus, preferably belonging to the genera Asperαillus or Fusarium. 9. Detergent according to Claims 1 - 8, wherein the amide 5 is a carboxylic acid amide, preferably a carboxylic acid amide with 3-12 carbon atoms, more preferably a fatty acid amide or a dicarboxylic acid diamide. 10. Detergent according to Claims 1 - 8, wherein the amide is a partial hydrolysis product of TAED (tetracetyl ethylene 0 diamine) , preferably DAED (diacetyl ethylene diamine) . 11. Detergent according to Claims 1 - 10, wherein the amide is present in an amount between 0.1 and 5 moles of amide per kg of the total detergent. 12. Detergent according to Claims 1 - 11, wherein the 5 detergent also contains a lipase and/or a protease and/or an amylase and/or a cellulase. 13. Use of the detergent according to Claims 1 - 12, wherein the detergent is used for bleaching of laundry in a washing solution with a temperature of between 10 and 60"C, a 0 pH of 7.5-11, with a concentration of the detergent of between 1 and 10 g/1. 14. Use according to Claim 13, wherein the temperature is between 25 and 55°C, the pH is between 9 and 10, the concen¬ tration of the detergent is between 2 and 5 g/1. 25 15. Use according to Claim 13 or 14, wherein the use is performed as a main wash. 16. Use according to Claim 13 or 14, wherein the use is performed as a soaking process.

Inventors: DAMHUS TURE, KIRK OLE, DAMHUS, TURE, KIRK, OLE
Applicants: NOVONORDISK AS, NOVO-NORDISK A/S
Application year: 1989
Main classification: C11D3
IPC codes: C11D3, C11D7