CA2249591A1 - N-acyl ethylenediaminetriacetic acid surfactants as enzyme compatible surfactants, stabilizers and activators - Google Patents

Abstract

Compositions including one or more enzymes and as the compatible chelating surfactant, salts of N-acyl ethylenediaminetriacetic acid ("ED3A"). Salts of N-acyl ED3A do not readily denature various enzymes, and thus are highly compatible with such enzymes, and enhance their detergent effectiveness to an unexpected degree.

Description

CA 02249~91 1998-09-21 W O 97/40129 PCT~US97/04048 N-ACYL ~ yLENEDIAMINETRIAcETIc ACID SURFACTANT~ AS
ENZYME COMPATIBLE SURFACTANTS~ STAB~,~7,FR-S AND ACTIVATORS

BACKGROUND OF THE INVENTION
EthylenPrli~min~triacetic acid (ED3A) and its salts (such as its alkali metal salts, including ED3ANa3) have applications in the field of chPl~ting çll~mi~try, and may be used as a starting material in the preparation of strong chelating polymers, oil soluble rhPl~ntc, surf~rt~nt~ and others. Conventional routes for the synthesis of ethylenPAi~ l. iacetic acid were achieved via its N-benzyl derivative, which wassubsequently hydrolyzed in ~lk~lin~ solutions to ED3ANa3, thus avoiding cyclization to its 2-oxo-1,4-piper~7in~ retic acid (3KP) derivative. One example of the synthesis of ethylene~ minP-N,N,N'-triacetic acid is disclosed in C~zemical Abstracts 7~, Vol. 71, page 451, no. 18369c, 1969. There it is stated that ethylenP~ minP reacts with ClH2CCO2H in a 1:3 molar ratio in basic solution at 10~C for 24 hours to form a mixture from which ethylen~ minP-N,N,N'-triacetic acid can be separated by complexing the same with Co(III). The resulting cobalt complexes can be isolated through ion exchange.
U.S. Patent No. 5,250,728, the disclosure of which is hereby incorporated by cr~çcllce, discloses a simple process for the synthesis of ED3A or its salts in high yield.
Specifically, a salt of N,N'-ethylenP~ minP~ cetic acid (ED2AH2) is condensed with stoichiometric amounts, preferably slight molar excesses of, form~l~1çllyde, at telllpe~dlul~
between 0~ and 110~C, preferably 0~ to 65~C and pH's greater than 7.0 to form a stable 5-mell,b._led ring intermP(li~tf~. The addition of a cyanide source, such as gaseous or liquid hydrogen cyanide, aqueous solutions of hydrogen cyanide or alkali metal cyanide, in stoichiometric amounts or in a slight molar excess, across this cyclic material at ten~eld~uf~s between 0~ and 110~C, preferably between 0~ and 65~C, forms ethylen~ minP N,N'-~ etir acid-N'-cyanomethyl or salts thereof (mononitrile-diacid).
The nitrile in aqueous solutions may be spontaneously cyclized in the presence of less than 3.0 moles base: mole ED2AH2, the base including alkali metal or ~Ik~lin~ earth metal hydroxides, to form 2-oxo-1,4-piper~7.inP~ cetic acid (3KP) or salts thereof, which is the desired cyclic int~rme~ te. ~n the presence of excess base, salts of ED3A are formed in CA 02249~91 1998-09-21 - W O 97/40129 PCT~US97104048 - excellent yield and purity. This patent also discloses an ~ e embo~1im~nt in which the ~ hlg material is ED2AHaXb, where X is a base cation, e.g., an alkali or ~Ik~lin~
earth metal, a is 1 to 2, and b is 0 to 1 in aqueous solutions. The reaction mixture also can be acidified to ensure complete formation of carboxymethyl-2-oxopiperazine (the S lactam) prior to the reaction. Form~ hyde is added, essenti~lly resulting in the hydroxymethyl derivative. Upon the addition of a cyanide source, 1-cyanomethyl-4-carboxymethyl-3-ketopiperazine (mononitrile monoacid) or a salt thereof is formed. In place of CH2O and a cyanide source, HOCH2CN, which is the reaction product of form~l~ellyde and cyanide, may also be employed in this method. Upon the addition of any suitable base or acid, this material may be hydrolyzed to 3KP. The addition of a base will open this ring structure to form the salt of ED3A.
U.S. Patent No. 5,284,972, the disclosure of which is hereby incorporated by lerclcllce, discloses N-acyl ED3A derivatives and a process for producing the same. The production of N-acyl derivatives of ethylen~ minPtriacetic acid can be accomplished according to the following general reaction scheme:
NaOH
ED3ANa3 + Acyl chloride > N-Acyl ED3ANa3 + NaCI

The starting ED3A derivative can be the acid itself, or suitable salts thereof, such as alkali metal and ~lk~line earth metal salts, preferably sodium or pot~sil-m salts.
Saturated N-Acyl ED3A derivatives that are the product of the foregoing reactioncan be ~lcsenled by the following ch~mir~l formula:

CnH2n+, - C - N - CH2CH2 - N

COOH
wl~lein n is from 1 to 40. Where unsaturation occurs, the strucnlre may be shown as follows:
~5 - W O 97/40129 PCT~US97/04048 Il /
CnH2n l - C - N - CH2CH2 - N
1 \

COOH
where n is from 2 to 40. As ulLsaLulaLion increases, the forrnulae are:

Il /
CnH2n 3 - C - N - CH2CH2 - N

COOH
where n is 3 to 40;

Il /
CnH2ns - C - N - CH2CH2 - N

COOH
where n is 4 to 40; and 1~ /
CnH2n 7 - C - N - CH2CH2 - N

COOH
where n is 5 to 40, etc.
Poly N-acyl ethylenP~ min~triacetic acid derivatives, such as dicarboxylic acid derivatives having the following general formula also can be produced:

N - CH2CH2 -N -C -(CH2),~ - C - N - CH2CH2 - N

COOH COOH

CA 02249~91 1998-09-21 - Wo 97/40129 PCT/USg7/04048 or:
HOOCCH2 ~
\ N - CH2CH2 -N -C -(CH2)X - COOH
HOOCCH2 Cl H2 COOH
where x is 1 to 40. Specific examples include mono and di ED3A derivatives such as oxalyldi ED3A, oxalylmono ED3A, maleylmono ED3A, maleyldi ED3A, succinoylmono ED3A, succinoyldi ED3A, etc.
In view of this relatively new technology, ethylenPdi~minptriacetic acid (ED3A) and its salts now can be readily produced in bulk and high yield.
Enzymes, such as proteases, lipases and amylases, are commonly used to enhance the performance of fabric delelg~ , dish washing liquids, hard surface cleaners, drain opening fluids, etc. By using such an enzyme in a deLelgellt, it is possible to hydrolyze the proteins or starch residues on fabrics to such a degree that they become readily soluble in water. Thus, a more effective removal of difficult protein or starch stains, including blood, mucus, and sweat, food products, etc. can be achieved. Moreover, since insoluble proteins and starches cause dirt to-adhere strongly to fabrics, increasing the protein and starch solubility helps remove dirt as well. Commercial enzymes are produced mainly by living cells such as yeasts, and are proteinaceous in nature. Enzymes with enh~nred activity for commercial use are often produced by genetic engineering.
The type of enzyme used depends on the detergellL formulation and application conditions, especially since any given enzyme typically exhibits a maximum effectiveness at spe~ific pH's and temperatures. Above their peak effectiveness te~ eldLure, they usually become denatured and never regain their activity. Enzymes are often denatured or deactivated by harsh surfactants such as sodium lauryl sulfate or linear alkyl benzene sulfate that are also common to delelg~llL formulations. It is believed that this denaturing or deactivation is due to the disturbance of the three dim~n~ional structure of the protein.
Metal ions such as copper+2, iron, nickel+~, cobalt, etc. can also deactivate enzymes, possibly by interacting with and blocking the active site of the enzyme.
It is therefore an object of the present invention to provide enzyme compatible surfact~nt~

CA 02249~91 1998-09-21 - W O97/40129 PCTrUS97/04048 It is a further object of the present invention to provide del~,rgel.l compositions cont~ining an enzyme and an enzyme comp~tihle surfactant.
It is an even further object of the present invention to enh~n~e the delergellL power of a del~r~ l composition with an N-acyl ED3A surfactant that is compatible with the enzyme in the deter~e,.l composition.

SUMMARY OF THE INVENTION
The problems of the prior art have been overcome by the present invention, whichprovides compositions including one or more enzymes and one or more surfact~ntc,provided that at least one of the surf~l~t~ntc is an N-acyl ethylen~ min~triacetic acid or salt thereof. Surprisingly, the present inventors have found that N-acyl ED3A is highly compatible with various enzymes, and enh~n~es their del~lge~-L effectiveness to an unexpected degree. Thue use of such surfactants with other enzyme systems, such as industrial processes, is also contemplated.
DETAILED DESCRIPI'ION OF THE INVENTION
Suitab}e acyl groups in the N-acyl ED3A surfactant include straight or branched aliphatic or aromatic groups cont~ining from 1 to 40 carbon atoms, such as pentanoyl, hexanoyl, heptanoyl, octanoyl, nananoyl, decanoyl, lauroyl, myristoyl, palmitoyl, oleoyl, stearoyl and nonanoyl. Examples of suitable branched acyl groups include neopentanoyl, neoheptanoyl, neodecanoyl, iso-octanoyl, iso-nananoyl and iso-tridecanoyl. Suitable aromatic acyl groups include benzoyl and napthoyl. The fatty acid chains may be sllbstit~1te~l, such as by one or more halogen and/or hydroxyl groups. Examples of hydroxy-substituted fatty acids including ipurolic (3,11-dihyroxytetr~c~noic), ustilic (2,15, 16-trihydroxyh.~ c~nnic), ambrettolic (16-hydroxy-7-h~x~ec~n-)ic), ricinoleic (12-hydroxy-cis-9-oct~ cenoic), ricinelailic (12-hydroxy-trans-9-oct~ecenoic), 9,10-dihydroxyoct~-lec~noic, 12-hydroxyoct~dec~nr ic, kalmlolenic (18-hydroxy-8,11,13-oct~-lec~ttienoic), ximenynolic (8-hydroxy-trans-l l-oct~lecenp-9-ynoic)~ isanolic (8-hydroxy-17-oct~decen~-9,11-diynoic) and lequerolic )14-hydroxy-cis-11-eicosenoic), as well as acyl derivatives of the above (the above named derivatives wherein the suffix "oic" is replaced by "oyl chloride"). Suitable halogen- substituted fatty acids include trifluoromethylbenzoyl chloride, pent~lec~fluoro-octanoyl chloride, pentafluoropropionoyl CA 02249~91 1998-09-21 - W O 97/40129 PCT~US97/04048 - chloride, pent~flllQrobenzoyl chloride, perfluorostearoyl chloride, perfluorononamoyl chloride, perfluoroheptanoyl chloride and trifluoromethylacetyl chloride. Preferably, the N-acyl group contains from 8 to 18 carbon atoms.
The surfactant propellies of N-acyl ED3A molecules allow for dispersion of fattysoils and thus enh~nre the activity of lipases against fatty soils. As the interfacial tension between the aqueous phase and the oily phase is rec~uced, interfacial area is increased, allowing th~e enzyme in the aqueous phase more surface to attack, thereby increasing the rate of reaction. Fnh~nrecl wetting of soils allows for more efficient attack by the enzymes, such as proteases, on deposited proteinaceous soils.
In addition, the stability of N-acyl ED3A is not inhibited by the presence of excess electrolyte, such as sodium chloride, and multivalent hardness ions, such as Ca++ and Mg++. Surprisingly, the present inventors have found that such electrolytes and hardness ions actually signifi~ntly enh~nre the lather stability of alkali metal N-acyl ED3A. The ability of N-acyl ED3A to sequester transition and heavy metal ions also alleviates the potential for the enzyme activity to be reduced as a result of these ions.
The N-acyl ED3A is preferably used in the form of its salts, in view of their solubility. Where the N-acyl ED3A acid is first produced, it can be readily converted into salts by partial or complete neutralization of the acid with the applupliate base. The acid also can be produced from N-acyl ED3A salts by neutralization of the base with aqll~ntit~tive amount of acid. The ~lerelred chelating surfart~ntc for use in the d~lelgelll compositions of the present invention are sodium and potassium lauroyl-ED3A. Other suitable counterions include triethanolamine, llieth~nnlamine, monoethanolamine,ammonium, isopropyl amine, N-propylamine and amino alcohols such as 2-amino-1 butanol, 2-amino-2-methyl-1,3-propane diol, 2-amino-2-methyl-1-propanol, 2-amino-2-ethyl-1,3-propane diol and Tris(hydroxylmethyl) aminom~th~nP.
The N-acyl ED3A salt can be used in the delelg~,ll compositions of the present invention alone or in combination with other surfactants. Preferably the total amount of surfactant in the composition is between about 5 to about 30%, more preferably from about 10 to about 25~, most preferably about 12%. The pH of the delergenl composition depends in part on the particular enzyme being used, but generally is within a range of about 7 to about 12.

CA 02249~91 1998-09-21 Suitable enzymes include proteolytic enzymes such as Alcalase~, Esperase~, Savinase~, and Du~zylllTM, amylases such as Tellllall~yl~, BAN, lipases such as Lipolasel, and cellulases. Savinaser, for example, is a serine protease having an oplilllulll pH of 9-11 and an OplilllullltellllJelature of 55~C. Avinasea', for example, has an OplilllUlll pH of about 6-8 and an uplllllulll ~elll~el~ture of about 60~C. Lipases have the ability to decompose hydrophobic substances (such as hydrophobic triglycerides) into more hydrophilic compounds which are more easily removed by d~Lelgelll action.
In addition to the surfactant, delelgellL form~ tions typically comprise about 13-25% builder, such as nitrilotriacetic acid, phosphates and zeolites. Up to about 25%
bleach persalts also can be added. Conventional surfactants that may be used in combination with the N-acyl ED3A include anionics such as sarcosinates (including oleoyl, lauroyl and myristoyl), soluble linear alkylbenzene sulfonate, alkyl sulfate and alkyl ethoxy sulfates, sodium lauryl ether sulfate; nonionics such as alcohol ethyoxylates and alkyl polyglycosides; cationics such as Cl2-Cl4 trimethyl ammonium chloride, di-tallow di-methyl ammonium chloride; and di-tallow methylamine, etc., and many of the foregoing are often used in combination, such as a binary lni~lule of linear alkylbenzene sulfonate and alcohol ethoxylates.
Other ingredients conventionally added to delelgelll compositions may be included, such as soap, dyes, perfumes, thickeners, conditioners, emollients, burrelillg agents, opacifiers, preservatives, optical brightent-rs, fabric softeners, etc.
Examples of suitable formulations are as follows:
Traditional Type European Heavy Duty Deter~ell~
Sodium lauroyl ED3A 5-20 %
Nonionics 1-7 %
Sodium triphosphate 0-30%
Zeolite 0-35 %
Sodium perborate/bleach activator 10-25 %
Sodium carbonate 2-15%
Sodium silicate 0-10%
Complexing agent 0-1%
Polycarboxylates 0-3 %
Optical brighteners, perfume 0.4-0.5%

CA 02249~91 1998-09-21 wo 97/40129 PcTrus97/o4o48 Enzymes: Alcalase 2.0 T or 0.4-0.8%
Durazym 6.0 T or 0.3-0.8%
Esperase 4.0 T or 0.4-0.8%
Savinase 6.0 T 0.3-0.6%
Lipolase 100 T 0.2-0.6%
Termamyl 60 T 0.4-0.8%
Celluzyme 0.7 T 1.0-3.0%
Sodium sulphate, water, etc. R~l~nre to 100%
pH 9.5-10.5 Compact Type Heavy Duty Det~lgenl Sodium myristoyl ED3A 5-35 %
Nonionics 1-15 %
Sodium triphosphate 0-40%
Zeolite 0-40%
Sodium perborate/bleach activator 15-30%
Sodium silicate 2-10%
Sodium carbonate 5-20 %
Complexing agent (phosphonate, citrate) 0-1 %
Polycarboxylates 0-3 %
Optical bri~hte~
perfume 0.4-0.6%
Enzymes: Durazym 6.0 T or 0.6-1.5 %
Esperase 4.0 T or 0.6-1.5 %
Savinase 6.0 T or 0.6-1.5%
Lipolase 100 T 0.3-0.8%
Termamyl 60 T 0.2-1.0%
Celluzyme 0.7 T 1.2-3.0%
Sodium sulphate, water, etc. R~l~nre to 100%
pH 9.5-11 Heavy Duty Liquid Del~ enl Triethanol amine oleoyl ED3A 5-35%
Nonionics 3-20 %
Sodium triphosphate 0-30%
Zeolite 0-30%
Complexing agent (phosphonate, citrate) 1-5 %
Polycarboxylates 0-5 %
Optical brighle~
perfume 0.1-0.5%

CA 02249~91 1998-09-21 wo 97/40129 PcrluS97104048 Enzymes: Alcalase 2.5 L or 0.4-1.0 %
Durazym 16.0 L or 0.2-0.6 %
Esperase 8.0 T or 0.4-1.0 %
Savinase 16.0 L or 0.2-0.6%
Termamyl 300 L 0.2-0.6%
Water 30-50 %
p H 7.0-9.5 Automatic Dishwashin~ D~Lelgel~l Sodium myristoyl ED3A 2-5 %
Sodium triphosph~te 0-40 %
Sodium pell,ol~t~/bleach activator 4-20%
Sodium silicate 5-30%
Polycarboxylates 0-3 %
Complexing agent (phosphonate, citrate) 0-35 %
Enzymes: Durazym 6.0 T 1-3 %
Esperase 6.0 Tr 1-3 %
Savinase 6.0 T 1-3%
Termamyl 60 T 1-3 %
Sodium sulphate, water, etc. R~l~n~.e to 100%
pH 9.5-11.0 E X A~IPL E 1 Myristoyl and lauroyl ED3A acids were neutralized with aqueous sodium hydroxide to produce a 20% wt. AI solution. The resulting sodium lauroyl ED3A and sodium myristoyl ED3A were used at a concentration of 0.2% wt. Ten grams of surfactant (20%wt. AI) were added to 990 grams of distilled deionized water to produce the 0.2% wt. solution.
One millilit~r of protease enzyme (Savinase~4 16.0 L type EX available commercially from Novo Nordisk) was diluted to 100 ml. with distilled deionized water.
1.43 ml of the enzyme solution was then added to four of five Tergotometer cells and allowed to acclimate for 20 minlltes. The cell contents were as follows:

CA 02249~9l l998-09-2l Table 1: Cell Contents Contents Cell 1 0.2 % wt sodium lauroyl ED3A
Cell 2 0.2 % wt sodium myristoyl ED3A
Cell 3 0.00143% wt protease enzyme Cell 4 0.2 % wt sodium lauroyl ED3A & 0.00143% wt Protease enzyme solution Cell 5 0.2 % wt sodium myristoyl ED3A & 0.00143% wt Protease enzyme solution Cotton test swatches soiled with blood/ink/milk were placed in each cell and allowed to soak for 90 minlltes. The tergotometer was activated and the swatches were ~ washed for thirty minutes. After thirty minutes, the wash water was ~lec~nte~l. One liter of distilled, deionized water was then added to each cell and the cells were placed back into the tergotometer, which was then activated for 10 minutes. The water was then ~lecantP~l and the test fabric was removed and placed on a piece of white cardboard. The fabric was allowed to air dry overnight.
Reflect~nre was measured using a photovolt detector with a d~telgelll head and green filter. Four reflectance measurements were recorded for each test fabric, two measurements per side. Initial and final reflect~nre results are shown in Table 2. The difference in reflect~nre between the initial and ~inal values are shown in Table 3. The change in reflectance due to enzyme activity is shown in Table 4.

CA 02249~91 1998-09-21 - W O 97/40129 PCTrUS97/04048 Table 2: Reflectance Values Initial Values Position Position Position Position S Cell # Swatch # 1 2 3 4 Average 7 26.4 26.6 26.9 26.9 26.7 2 3 26.4 26.6 27.1 26.9 26.8 3 16 26.9 27.1 26.6 26.4 26.8 4 1 26.5 26.6 27.5 27.3 27.0 12 26.4 26.9 27.3 27.3 27.0 23 26.9 27.5 27.5 27.5 27.4 2 24 25.8 25.8 25.8 25.8 25.8 3 5 27.3 27.5 27.7 27.7 27.6 4 13 28.5 28.5 28.5 28.5 28.5 22 27.5 27.2 27.8 27.8 27.6 Final Values Position Position Position Position Cell # Swatch # 1 2 3 4 Average 1 7 61.4 61.6 61.6 61.8 61.6 2 3 60.5 60.5 60.7 60.5 60.6 3 16 58.9 58.9 58.5 59.3 58.9 4 1 74.2 74.4 74.4 74.6 74.4 12 73.5 73.7 74 73.7 73.7 1 23 62 62 62 62 62.0 2 24 59.1 59.7 59.3 59.3 59.4 3 S 60.1 59.7 59.7 58.9 59.6 4 13 74.8 74.8 74.8 74.4 74.7 S 22 72.9 73.5 73.3 73.3 73.3 CA 02249~9l l998-09-2l W O 97/40129 PCTrUS97/04048 Table 3: Delta Reflectance Initial Final Delta 2-Swatch System Cell Swatch Average Average Average Average # #
NaLEDA3A 1 7 26.7 61.6 34.9 NaLEDA3A 1 23 27.4 62.0 34.7 34.8 NaMED3A 2 3 26.8 60.6 33.8 NaMED3A 2 24 25.8 59.4 33.6 33.7 Enzyme 3 16 26.8 58.9 32.2 Enzyme 3 5 27.6 59.6 32.1 32.1 NaLED3A+Enzyme 4 l 27.0 74.4 47.4 NaLED3A+Enzyme 4 13 28.5 74.7 46.2 46.8 NaMED3A+Enzyme 5 12 27.0 73.7 46.8 NaMED3A+Enzyme 5 22 27.6 73.3 45.7 46.2 Table 4 Cell Delta Due to Enzyme 4-1 12.0 5-2 12.5 The results demonstrate the compatibility of N-acyl ED3A with protease enzyme. In addition, the presence of the N-acyl ED3A significantly enh~nre~l the cleaning power of the enzyme system. The presence of the enzyme also enh~n~e~l the cleaning power of the surfactant solution (relative to the cleaning power of the surfactant solution alone), contributing an extra 12 points of brightn~s.

CA 02249~91 1998-09-21 - W O 97/40129 PCT~US97/04048 Myristoyl and oleoyl ED3A acids were neutralized with aqueous sodium hydroxide to produce a 20% wt. AI solution. In addition, a linear alkyl benzene sulfonate, namely, a 40%wt AI sodium dodecylbenzene sulfonate solution (SLlcl)allLall DS-40) was diluted with distilled deionized water to produce a 20%wt AI solution.
The aforemP-ntioned solutions, along with a solution of lauroyl ED3A, were evaluated at a concentration of 12.5%wt in a base d~Lcrgent having the followingformulation:
zeolite A 30.2 wt%
sodium carbonate 20.8 wt%
sodium sulfate 30.2 wt%
sodium silicate 5.2 wt%
cmc 1.0 wt%
The overall deLel~ L collcellLralion tested was 3.5 grams of detel~e,lL/liter of water.
Thus, the amount of dry del~lgelll charged into each cell was 3.06 grams, whereas the amount of liquid surfactant charged to each cell was 2.18 grams (using 20%wt AI
surfactant). The exact weights used are shown in Table 5 below:

Surfactant Surfactant Wt Detergent Wt Cell 1 LABS 2.1876 3.0615 Cell 2 NaMED3A 2.1880 3.0634 Cell 3 NaOED3A 2.1853 3.0634 Cell 4 LABS 2.1887 3.0648 Cell 5 NaMED3A 2.1890 3.0637 Cell 6 NaOED3A 2.1860 3.0629 Enzyme was added to cells 4, 5 & 6 The surfactant portion of the detelgel,L was added to each cell (cont~ining one liter of distilled deionized water). The pH was adjusted to 8.3 with dilute NaOH. The rem~ining portion of the detefgent was then added to the solution. The temperature of the solution CA 02249~91 1998-09-21 - W O 97/40129 PCTrUS97/04048 - in each cell was 48~C and the pH was 10.5.
One milliliter of protease enzyme (Savinase~4 16.0 L type EX available commercially from Novo Nordisk) was diluted to 100 ml. with distilled deionized water.
1.43 ml of the enzyme solution was then added to three of six Tergotometer cells and S allowed to acclimate for 10 minutes.
Cotton test swatches soiled with blood/ink/milk were placed in each cell and thetergotometer was activated and the swatches were washed for thirty minutes. After thirty minutes, the wash water was dec,~nt~d. One liter of distilled, deionized water was then added to each cell and the cells were placed back into the tergotometer, which was then activated for 10 minlltes. The water was then dec~nted and the test fabric was removed and placed on a piece of white cardboard. The fabric was allowed to air dry overnight.
Reflectance was measured using a photovolt detector with a detergent head and green filter. Four reflectance measurements were recorded for each test fabric, two measurements per side. Initial and final reflect~n~.e results are shown in Table 6. The change in reflec,t~n~,e due to detergency is presented in Table 7. The change in reflectance due to enzyme activity is shown in Table 8.

CA 02249~91 1998-09-21 - W O 97/40129 PCT~US97/04048 Table 6: Reflec.t~n~e Values Initial Values Position Position Position Position Cell # Cloth # 1 2 3 4 Average 1 16 27 27.4 26.5 26.5 26.9 13 26.9 26.9 27.1 27.1 27.0 2 21 26.3 26.5 27.3 27.5 26.9 2 17 26.9 26.7 27.3 27.3 27.1 3 19 27.4 27.3 26.5 26.5 26.9 3 22 26.5 26.7 27.5 27.5 27.1 4 12 26.5 26.3 27.5 27.5 27.0 4 6 27.8 27.7 26.4 26.4 27.1 S 26.6 26.4 27.4 27.4 27.0 3 27.5 27.7 26.7 26.5 27.1 6 24 26.3 26.3 27.8 27.5 27.0 6 23 27.5 27.5 26.7 26.7 27.1 After Wash Position PositionPositionPosition Cell # Cloth # 1 2 3 4 Average 1 16 75.4 75.4 75.2 75.4 75.4 13 75 75 75.2 75.4 75.2 2 21 65.7 65.9 65.9 66.1 65.9 2 17 69 68.8 68.8 68.8 68.9 3 19 71.1 71.1 71.1 71.1 71.1 3 22 70 69.6 69.8 69.6 69.8 4 12 74.4 74.4 74.6 74.8 74.6 4 6 76 76 76 76.2 76.1 70.2 70.2 70.2 70.4 70.3 3 71.1 71.5 71.3 71.3 71.3 6 24 71.5 71.7 71.3 71.5 71.5 6 23 72.9 72.9 73.7 73.3 73.2 CA 02249~9l l998-09-2l - W O 97/40129 PCTrUS97/04048 Table 7: Delta Reflectance Initial Final Delta 2-Swatch Cell # Cloth # Average Average Average Average 16 26.9 75.4 48.5 1 13 27.0 75.2 48.2 48.3 2 21 26.9 65.9 39.0 2 17 27.1 68.9 41.8 40.4 3 19 26.9 71.1 44.2 3 22 27.1 69.8 42.7 43.4 4 12 27.0 74.6 47.6 4 6 27.1 76.1 49.0 48.3 27.0 70.3 43.3 3 27.1 71.3 44.2 43.8 6 24 27.0 71.5 44.5 6 23 27.1 73.2 46.1 45.3 Table 8: Change Due to Enzyme Cell # Delta Reflectance 4-1 0.0 5-2 3.3 6-3 1.9 The linear alkylbenzene sulfonate deactivated the enzyme completely, and there was no increase in brightness between systems 1 and 4. However, systems 5 and 6 produced significantly higher values than systems 2 and 3. In the case of myristoyl ED3A, the presence of the enzyme increased brightnPs~ by 3.3 points. The n-acyl ED3A
was compatible with the enzyme.

Claims (10)

What is claimed is:

1. A detergent composition containing an enzyme and a salt of N-acyl ethylenediaminetriacetic acid, wherein said acyl group is a straight or branched aliphatic or aromatic group containing from 1 to 40 carbon atoms.

2. The detergent composition of claim 1, wherein said enzyme is selected from the group consisting of proteases, amylases, lipases and cellulases.

3. The detergent composition of claim 1, wherein said enzyme is a protease.

4. The detergent composition of claim 1, wherein said acyl group contains from 8 to 18 carbon atoms.

5. The detergent composition of claim 1, wherein said salt of N-acyl ethylenediaminetriacetic acid is an alkali metal salt.

6. The detergent composition of claim 1, wherein said salt of N-acyl ethylenediaminetriacetic acid is an alkanol amine salt.

7. The detergent composition of claim 1, wherein said salt of N-acyl ethylenediaminetriacetic acid is an amino alcohol salt.

8. The detergent composition of claim 1, wherein said acyl group is selected from the group consisting of lauroyl, oleoyl and myristoyl.

9. The detergent composition of claim 8, wherein said acyl group is lauroyl.

10. The detergent composition of claim 1, further comprising a builder.