suitable acyl groups in the n - acyl ed3a surfactant include straight or branched aliphatic or aromatic groups containing 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 substituted , such as by one or more halogen and / or hydroxyl groups . examples of hydroxy - substituted fatty acids including ipurolic ( 3 , 11 - dihyroxytetradecanoic ), ustilic ( 2 , 15 , 16 - trihydroxyhexadecanoic ), ambrettolic ( 16 - hydroxy - 7 - hexadecanoic ), ricinoleic ( 12 - hydroxy - cis - 9 - octadecenoic ), ricinelailic ( 12 - hydroxy - trans - 9 - octadecenoic ), 9 , 10 - dihydroxyoctadecanoic , 12 - hydroxyoctadecanoic , kaimlolenic ( 18 - hydroxy - 8 , 11 , 13 - octadecatrienoic ), ximenynolic ( 8 - hydroxy - trans - 1 1 - octadecene - 9 - ynoic ), isanolic ( 8 - hydroxy - 17 - octadecene - 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 &# 34 ; oic &# 34 ; is replaced by &# 34 ; oyl chloride &# 34 ;). suitable halogen - substituted fatty acids include trifluoromethylbenzoyl chloride , pentadecafluoro - octanoyl chloride , pentafluoropropionoyl chloride , pentafluorobenzoyl chloride , perfluorostearoyl chloride , perfluorononamoyl chloride , perfluoroheptanoyl chloride and trifluoromethylacetyl chloride . preferably , the n - acyl group contains from 8 to 18 carbon atoms . the surfactant properties of n - acyl ed3a molecules allow for dispersion of fatty soils and thus enhance the activity of lipases against fatty soils . as the interfacial tension between the aqueous phase and the oily phase is reduced , interfacial area is increased , allowing the enzyme in the aqueous phase more surface to attack , thereby increasing the rate of reaction . enhanced 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 significantly enhance 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 appropriate base . the acid also can be produced from n - acyl ed3a salts by neutralization of the base with a quantitative amount of acid . the preferred chelating surfactants for use in the detergent compositions of the present invention are sodium and potassium lauroyl - ed3a . other suitable counterions include triethanolamine , diethanolamine , 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 ) aminomethane . the n - acyl ed3a salt can be used in the detergent 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 detergent composition depends in part on the particular enzyme being used , but generally is within a range of about 7 to about 12 . suitable enzymes include proteolytic enzymes such as alcalase . sup .•, esperase . sup .•, savinase . sup .•, and durazym ™, amylases such as termamyl . sup .•, ban , lipases such as lipolase . sup .•, and cellulases . savinase . sup .•, for example , is a serine protease having an optimum ph of 9 - 11 and an optimum temperature of 55 ° c . avinase . sup .•, for example , has an optimum ph of about 6 - 8 and an optimum temperature 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 detergent action . in addition to the surfactant , detergent formulations 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 , allyl sulfate and alkyl ethoxy sulfates , sodium lauryl ether sulfate ; nonionics such as alcohol ethyoxylates and alkyl polyglycosides ; cationics such as c 12 - c 14 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 mixture of linear alkylbenzene sulfonate and alcohol ethoxylates . other ingredients conventionally added to detergent compositions may be included , such as soap , dyes , perfumes , thickeners , conditioners , emollients , buffering agents , opacifiers , preservatives , optical brighteners , fabric softeners , etc . ______________________________________traditional type european heavy duty detergentsodium lauroyl ed3a 5 - 20 % nonionics 1 - 7 % sodium triphosphate 0 - 30 % zeolite 0 - 35 % sodium perborate / bleach 10 - 25 % activatorsodium carbonate 2 - 15 % sodium silicate 0 - 10 % complexing agent 0 - 1 % polycarboxylates 0 - 3 % optical brighteners , 0 . 4 - 0 . 5 % perfumeenzymes : 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 . balance to 100 % ph 9 . 5 - 10 . 5compact type heavy duty detergentsodium myristoyl ed3a 5 - 35 % nonionics 1 - 15 % sodium triphosphate 0 - 40 % zeolite 0 - 40 % sodium perborate / bleach 15 - 30 % activatorsodium silicate 2 - 10 % sodium carbonate 5 - 20 % complexing agent ( phosphonate , 0 - 1 % citrate ) polycarboxylates 0 - 3 % optical brighteners , 0 . 4 - 0 . 6 % perfumeenzymes : 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 . balance to 100 % ph 9 . 5 - 11heavy duty liquid detergenttriethanol amine oleoyl ed3a 5 - 35 % nonionics 3 - 20 % sodium triphosphate 0 - 30 % zeolite 0 - 30 % complexing agent ( phosphonate , 1 - 5 % citrate ) polycarboxylates 0 - 5 % optical brighteners , 0 . 1 - 0 . 5 % perfumeenzymes : 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 % ph 7 . 0 - 9 . 5automatic dishwashing detergentsodium myristoyl ed3a 2 - 5 % sodium triphosphate 0 - 40 % sodium perborate / bleach 4 - 20 % activatorsodium silicate 5 - 30 % polycarboxylates 0 - 3 % complexing agent phosphonate , 0 - 35 % citrate ) 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 . balance to 100 % ph 9 . 5 - 11 . 0______________________________________ 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 milliliter of protease enzyme ( savinase 3 / 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 minutes . the cell contents were as follows : table 1______________________________________cell contentscontents______________________________________cell 1 0 . 2 % wt sodium lauroyl ed3acell 2 0 . 2 % wt sodium myristoyl ed3acell 3 0 . 00143 % wt protease enzymecell 4 0 . 2 % wt sodium lauroyl ed3a & amp ; 0 . 00143 % wt protease enzyme solutioncell 5 0 . 2 % wt sodium myristoyl bd3a & amp ; 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 minutes . the tergotometer was activated and the swatches were washed for thirty minutes . after thirty minutes , the wash water was decanted . 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 decanted 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 reflectance results are shown in table 2 . the difference in reflectance between the initial and final values are shown in table 3 . the change in reflectance due to enzyme activity is shown in table 4 . table 2______________________________________reflectance values position position position positioncell # swatch # 1 2 3 4 average______________________________________initial values1 7 26 . 4 26 . 6 26 . 9 26 . 9 26 . 72 3 26 . 4 26 . 6 27 . 1 26 . 9 26 . 83 16 26 . 9 27 . 1 26 . 6 26 . 4 26 . 84 1 26 . 5 26 . 6 27 . 5 27 . 3 27 . 05 12 26 . 4 26 . 9 27 . 3 27 . 3 27 . 01 23 26 . 9 27 . 5 27 . 5 27 . 5 27 . 42 24 25 . 8 25 . 8 25 . 8 25 . 8 25 . 83 5 27 . 3 27 . 5 27 . 7 27 . 7 27 . 64 13 28 . 5 28 . 5 28 . 5 28 . 5 28 . 55 22 27 . 5 27 . 2 27 . 8 27 . 8 27 . 6final values1 7 61 . 4 61 . 6 61 . 6 61 . 8 61 . 62 3 60 . 5 60 . 5 60 . 7 60 . 5 60 . 63 16 58 . 9 58 . 9 58 . 5 59 . 3 58 . 94 1 74 . 2 74 . 4 74 . 4 74 . 6 74 . 45 12 73 . 5 73 . 7 74 73 . 7 73 . 71 23 62 62 62 62 62 . 02 24 59 . 1 59 . 7 59 . 3 59 . 3 59 . 43 5 60 . 1 59 . 7 59 . 7 58 . 9 59 . 64 13 74 . 8 74 . 8 74 . 8 74 . 4 74 . 75 22 72 . 9 73 . 5 73 . 3 73 . 3 73 . 3______________________________________ table 3______________________________________delta reflectance cell swatch initial final delta 2 - swatchsystem # # average average average average______________________________________naled3a 1 7 26 . 7 61 . 6 34 . 9naled3a 1 23 27 . 4 62 . 0 34 . 7 34 . 8named3a 2 3 26 . 8 60 . 6 33 . 8named3a 2 24 25 . 8 59 . 4 33 . 6 33 . 7enzyme 3 16 26 . 8 58 . 9 32 . 2enzyme 3 5 27 . 6 59 . 6 32 . 1 32 . 1naled3a + 4 1 27 . 0 74 . 4 47 . 4enzymenaled3a + 4 13 28 . 5 74 . 7 46 . 2 46 . 8enzymenamed3a + 5 12 27 . 0 73 . 7 46 . 8enzymenamed3a + 5 22 27 . 6 73 . 3 45 . 7 46 . 2enzyme______________________________________ the results demonstrate the compatibility of n - acyl ed3a with protease enzyme . in addition , the presence of the n - acyl ed3a significantly enhanced the cleaning power of the enzyme system . the presence of the enzyme also enhanced the cleaning power of the surfactant solution ( relative to the cleaning power of the surfactant solution alone ), contributing an extra 12 points of brightness . 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 ( strepantan ds - 40 ) was diluted with distilled deionized water to produce a 20 % wt ai solution . the aforementioned solutions , along with a solution of lauroyl ed3a , were evaluated at a concentration of 12 . 5 % wt in a base detergent having the following formulation : ______________________________________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 detergent concentration tested was 3 . 5 grams of detergent / liter of water . thus , the amount of dry detergent 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 : table 5______________________________________ surfactant surfactant wt detergent wt______________________________________cell 1 labs 2 . 1876 3 . 0615cell 2 named3a 2 . 1880 3 . 0634cell 3 naoed3a 2 . 1853 3 . 0634cell 4 labs 2 . 1887 3 . 0648cell 5 named3a 2 . 1890 3 . 0637cell 6 naoed3a 2 . 1860 3 . 0629______________________________________ enzyme was added to cells 4 , 5 , & amp ; 6 the surfactant portion of the detergent was added to each cell ( containing one liter of distilled deionized water ). the ph was adjusted to 8 . 3 with dilute naoh . the remaining portion of the detergent was then added to the solution . the temperature of the solution in each cell was 48 ° c . and the ph was 10 . 5 . one milliliter of protease enzyme ( savinase 3 / 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 allowed to acclimate for 10 minutes . cotton test swatches soiled with blood / ink / milk were placed in each cell and the tergotometer was activated and the swatches were washed for thirty minutes . after thirty minutes , the wash water was decanted . 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 decanted 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 reflectance results are shown in table 6 . the change in reflectance due to detergency is presented in table 7 . the change in reflectance due to enzyme activity is shown in table 8 . table 6______________________________________reflectance values position position position positioncell # cloth # 1 2 3 4 average______________________________________initial values1 16 27 27 . 4 26 . 5 26 . 5 26 . 91 13 26 . 9 26 . 9 27 . 1 27 . 1 27 . 02 21 26 . 3 26 . 5 27 . 3 27 . 5 26 . 92 17 26 . 9 26 . 7 27 . 3 27 . 3 27 . 13 19 27 . 4 27 . 3 26 . 5 26 . 5 26 . 93 22 26 . 5 26 . 7 27 . 5 27 . 5 27 . 14 12 26 . 5 26 . 3 27 . 5 27 . 5 27 . 04 6 27 . 8 27 . 7 26 . 4 26 . 4 27 . 15 5 26 . 6 26 . 4 27 . 4 27 . 4 27 . 05 3 27 . 5 27 . 7 26 . 7 26 . 5 27 . 16 24 26 . 3 26 . 3 27 . 8 27 . 5 27 . 06 23 27 . 5 27 . 5 26 . 7 26 . 7 27 . 1after wash1 16 75 . 4 75 . 4 75 . 2 75 . 4 75 . 41 13 75 75 75 . 2 75 . 4 75 . 22 21 65 . 7 65 . 9 65 . 9 66 . 1 65 . 92 17 69 68 . 8 68 . 8 68 . 8 68 . 93 19 71 . 1 71 . 1 71 . 1 71 . 1 71 . 13 22 70 69 . 6 69 . 8 69 . 6 69 . 84 12 74 . 4 74 . 4 74 . 6 74 . 8 74 . 64 6 76 76 76 76 . 2 76 . 15 5 70 . 2 70 . 2 70 . 2 70 . 4 70 . 35 3 71 . 1 71 . 5 71 . 3 71 . 3 71 . 36 24 71 . 5 71 . 7 71 . 3 71 . 5 71 . 56 23 72 . 9 72 . 9 73 . 7 73 . 3 73 . 2______________________________________ table 7______________________________________delta reflectance initial final delta 2 - swatchcell # cloth # average average average average______________________________________1 16 26 . 9 75 . 4 48 . 51 13 27 . 0 75 . 2 48 . 2 48 . 32 21 26 . 9 65 . 9 39 . 02 17 27 . 1 68 . 9 41 . 8 40 . 43 19 26 . 9 71 . 1 44 . 23 22 27 . 1 69 . 8 42 . 7 43 . 44 12 27 . 0 74 . 6 47 . 64 6 27 . 1 76 . 1 49 . 0 48 . 35 5 27 . 0 70 . 3 43 . 35 3 27 . 1 71 . 3 44 . 2 43 . 86 24 27 . 0 71 . 5 44 . 56 23 27 . 1 73 . 2 46 . 1 45 . 3______________________________________ table 8______________________________________change due to enzymecell # delta reflectance______________________________________4 - 1 0 . 05 - 2 3 . 36 - 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 brightness by 3 . 3 points . the n - acyl ed3a was compatible with the enzyme .