CA1208578A - Liquid detergent composition with mixed enzyme formulation - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Enzyme-containing liquid detergent compositions are provided comprising 5 to 75% of one or more detergent surface active agents, preferably 10 to 60% of a C2-C3 alkoxylated C10-C18 alkanol nonionic detergent compound; from 25 to 85% water; and an enzyme mixture consisting essentially of an alkaline protease enzyme and an .alpha.-amylase enzyme in relative proportions such that the ratio of the enzyme activities in said mixture is from about 4,000 to about 80,000 Novo amylase units of .alpha.-amylase per Anson unit of protease, said protease being present in an amount to provide from about 0.25 to about 2.5 Anson units per 100 grams of detergent composition, the detergent composition being particularly adapted for use as a laundering or pre-soak formulation due to effective soil and stain removal characteristics.

Description

lZ~8S78 BACKGROUND OF THE INVENTION

This invention relate~, in general, to enzyme-contalning liquid detergent compositions which are suitable for launder-ing or pre-soak formulations. More particularly, the invention relates to detergent compositions containlng mixtures of pro-tease and amylase enzymes in defined proportions which provide particularly e~fective soil and ~tain removal during laundering.
The formulation of enzyme-containing liquid detergent com-positions has been the focus of much attention in the prior art.
The desirability of incorporating enzymes into detergent compo-sltions is primarily due to the effectiveness of proteolytic and amylolytic enzymes in decomposing proteinaceous and starchy ma-terials found on aoiled fabrics, thereby facilitatlng the removal of stains such as, gravy stains, blood stalns, chocolate stains and the like during launderlng. However, enzymatlc materials suitable for laundry composltions, particularly proteolytic en-zymes, ere relatively expensive. Indeed, they generally are the most expensive ingredients in a typical commercial liquid deter-gent composition, even when present ln relatively mlnor amounts.
Moreover, an excess of enzymes is generally required in the deter-gent ~ormulation, Because o~ the known instability Or enzyme~
in aqueous compositions an excess of enzymes is generQlly added to the formulation to compensate for the expected loss of enzyme ~ctivity during prolonged periods o~ storage. Consequently, the expense as~oclated with the use of enzymes in liquid detergent compositions has heretofore been a significant deterrent to their wide~pread commercial use

-2-- 12~85~78 Detergent compositions containing mixtures of enzymes, e.g.
proteases and amylases, have been broadly described in the prior art Thus, for example, U.S. Patent 3,630,930 describes a gran-ular detergent compo6ition containing from about 0.5 to 20~ of enzyme carrier granules, the enzyme granules being comprised of from about 0.001 to 10~ of mixtures of protease and amylase en-zymes in a weight ratio of protease to amylase of 50:1 to 1:5.
British Patent specification 1,240,058 discloses a granular deter-gent composition containing a mixture of protease and amylase en-zymes in a weight ratio of protease to amylase of 30:1 to 3:1, the weight percent of amylase in the composition being from 0 0003 to 3~. In U.S. Patent 35931,034 to Inamorato et al there is disclosed a granular detergent composition containing a mixture of alkaline proteQse ~nd~-amylase enzyme~ in a ratlo of actlvity varylng from 100,000 to 400,000 Novo amylase units of am~lase per Anson unit of protea~e Accordingly, while the use of enzyme mixtures in granular deter-gent compositions is generally disclosed in the patent literature, the mixtures themselves are, in most instances, so broadly described ~8 to encompas~, for example, mi~tures wherein the percent protease may vary wlthin 5 orders of ma~nitude (British Patent 1240058), or the percent amylase may vary within 5 orders of magnltude (U,S Patent 3,630,930), thereby encouraging the bellef that within such broad ranges, the greater the amount of enzyme used, the more effective the resultant stain removal. In addition, the aforemen-tloned patent6, ln common with the Inamorato et al patent are strictly related to granular compositions and hence provide no teaching regarding the use of enzyme mixtures ~n liquld composltlonJ-1~8578 3977 ',I~l/~nY ()1~ TNVli`NT:LON
-The present invention provides an enzyme-contalning liquid detergent composition comprising:
(a) from about 5 to about 75~, by weight, of one or more detergent surface active agents selected from the group consisting of anionic, nonionic, cationic, ampholytic and æwitterionic detergent compounds;
(b) from about 25 to ~5~ water; and (c) an enzyme mixture consisting essentially of an alkaline protease enzyme and an ~amylase enzyme in relative proportlons such that the ratio of the enzyme activities i8 from about 4,000 to about ~0,000 Novo amylase units of c~-amylase per Anson unlt of protease, said protease belng present in an amount to provide from about 0~25 to about 2.5 Anson unlts per 100 grams of detergent composition.
In accordance with ~he process of the lnventiong launder~ng of stained and/or soiled materlals is effected by contacting such materials wlth an a.queous solution of the above-de~lned liquid deter~ent compocitlon~
The present lnvention ls predlcated on the dlscovery that the amount of alkaline protease enzyme whlch iR ordlnarlly necessary ~orlthe removal o~ protelnaceous staln can be slgnificantly.reduced by the combination therewith of an amount o~ amylase enzyme in accordance with the invention so as to prov~de a detergent compo-sition ha.ving equlvalent or improved stain removal capabi.lities but at a considera.bly reduced formulation expense. Unlike the dis-closures in the art which recommend mixing proteases and amylases over broad ranees in deter~ent compositions, the enzyme mlxtures herein descrlbed are characterizcd by a synergistiç interaction of 12~85~8 protease and amylase, and encompass only those mixtures having a nar~owly defined ratio of activities The activities of the alkaline protease and cy-amylase enzymes are expressed in Anson units of protease, and Novo amylase units of amylase, respectively. These are units commonly used in the art to describe the activity, under common conditions, of enzyme formulations containing pro-tease or amylase enzymes.
In a preferred embodiment of the invention the enzyme mixtures contain relative amounts of alkaline protease and d-amylase to provide from about 10,000 to 50,000 Novo amylase units ofc~_amylase per Anson unit o~ protease, an activity ratio of from about 15,000 to 40,000 being even more preferred and a ratio of from about 30,000 to 40,000 belng especially deslrable The amount of the enzyme mixture present in the liquid detergent composition will, of course~ depend to some extent on the amount of the composition whlch is to be added to the wash solution. For detergent compositions lntended for use at concentratlons of about 0.15% ln the wash solutlon of an automakic home laundry machlne~ a suitable amount of mlxture wlll provide ~rom about 0.25 to ab~ut 2.5 An~on units of pro-tease per hundred grams of detergent composition, a ratio of from about 0.5 to 2 0 being preferred, and about 1.5 Anson units/
100 gram8 of compo~ition being a particularly preferred protease concentration.

DETAILED DESCRIPTION OF T B INVENTION

The activity Or the alkaline protease enzyme i8, as noted above, measured in terms of Anson units The Anson hemoglobin method for the measurement of An~on unit actlvity is a procedure well known in the art for determining the activlty of proteolytic ~8S78 enzymes, and is set forth in the "Journal of General Physiology", volume 22, pages 79-89 (1939), such disclosure being incorporated herein by re-ference. The modified Anson hemoglobin method may also be used for measuring the proteolytic activity, such modified method being described in the article "Alkali-Resistant Enzyme for Detergents", S. R. Green, Soap and Chemical Specialities, pages 86, 88, 90, 94 and 133, May 1968. In principle, the method employs the alkaline protease enzyme to digest a denatured hemoglobin substrate at standard conditions in a buffered aqueous medium at the selected pH, and the amoun~ of digested material is determined by a color test with phenol xeagent.
The activity of the ~-amylase enzyme is, as previously noted, measured in terms of Novo amylase units. The standard procedure for the measurement of such Novo units is a modifica-tion of the SKB method (Sandstedt, Kneen & Blish, Cereal Chemistry 16, 712, (1939)) without addition of beta-amylase.
In this procedure 20 ml of a buffered starch solution (prepared by the method described below) are measured in a test tube (diameter 24 mm, leng-th 190 mm) and placed in a water thermo-stat at a temperature of 37C. After a few minutes pre-warming, 10 ml of the amylase solution to be tesLcd (or v ml amylase solution ~ (10-v) ml water) is added. The contents of the tube are thorou~31y mixed and at the same tirne a skopwatch is started.
~t appropriate time intervals 1 ml of the reaction mixture is added to 5 ml of a dilute iodine solution (prepared by the method described below), shaken and transferred to a comparison tube, and the color is compared with the standard color. If the color endpoint is reached in less than 10 minutes, a more dilute amylase solution or a smaller volume oE arnylase solution is used.

~' :12~85'78 As colorimeter the Hellige Comparator 607 is used with the glass ~-amylase standard. (cf. Redfern Methods for determination of ~-amylase, Cereal Chemistry 24, 259, (1947)).
The ~-amylase - 6a --lZ~857t3 activity of the sample may be calculated by using the followlng form-ula:

A = 1430 x V where _ t x a x v A = q~amylase activity in Novo amylase unlts per gram t ~ time to reach the color endpoint ~minutes~
a = weight o~ sample in grams V = volume to which the sample i8 diluted ~ml) v = volume of amylase solution used (ml) The factor t'l430'l is not strictly constant but depends to some degree upon the starch quality used, For exact deter-minations, the value of the factor should be calculated by means of a commerclally available ~tandard amylafie preparation with known actlvity~
The "dilute iodine fiolution" mentioned above is prepared by dl~solving 1 ml of l'stock iodine solutlon" and 20 g of po-tassium iodide in ~u~ficient water to make 500 ml; the "6tock iodine solution" is prepared by dissolving 11 g of iodine crystals and 22 g of potasslum iodide in sufficient water to make 500 ml, The "bu~fered starch solution" mentioned above i3 prepared as follow~: 10 ~ soluble starch (e.g~ Merck, Amylum solubile~
Soluble Starch, Erg. B~6) calculated as dry matter are made into a slurry with some water, The slurry is added to about 200 ml of bolling water. When the starch is completely dissolvedJ the ~olutlon 18 cooled, transferred to a 1 llter volumetric flask and made up to the mark with water, The starch solutlon (made by dlssolvlng 9.36 g NaCl, 69.oo g KH2P04, 4,80 g Na2HP04, 2 H20 ln sufficient water to make 1 liter), Finally the solution ls saturated with toluene, The pH of the fini6hed buffered ~tarch solution should be 5,7. The starch solution must be as freshly prepared as pos~ible but can be 3tored in the refrlgerator for not more than 24 hourfi, Distilled water iB u~ed in all cases.

The enzyme activity of proteolytic and amylolytic enzyme preparations is ordinarily determined, as a practical matter, without conducting the above-described assay procedures.
For the majority of commercially available liquid enzyme prepar-ations containing protease or amylase enzymes, the enzyme activity is provided by the manufacturer and is expressed in Anson units, or Novo amyl.ase units (or units directly propor-tional thereto). Alternatively, the activity of a given enzyme preparation can be readily determined analytically by a procedure wherein the enzyme reactivity with a protein or starch substrate, as the case may be, is measured at standard conditions and then compared with the reactivity o:E reference enzyme preparations of known activity. In such analytical procedure, enzyme reactivity may be conveniently expressed as the optical densi,ty of a test solution contai,ning the enz.yme preparation and -the protei,n or starch substrate when measured at standard conditions, the higher the optical densi-ty, the greater the activity.
The suitable alkaline protr=olytic enzymes include the vari.ous rsommerical liquid enzyme preparati,ons which have been adapted for use i.n de-tergent compositions, enzyme preparati.ons in powdf-rrd Eorm being also useful. although, as a general rule, less ~onvenient for incorporation i.nto t~le~ presrent liquid detergent compositions. Thus, suitabl f' liquirl enzyme preparcl-ti.ons inc]ude "A].calase"* and "F.sperase"* sold by Novo Industries, Coprnhagen, Denmark, and "Maxatase"* and "AZ-Protease"* sold by Gist-Brocades, Delft, The Netherlands.
"Alcalase" is particularly preferred for the present compositions.
Among the suitable ~-amylase liquid erzyme preparations are those sold by Novo Industries and Gist-Brocades under the *Trade Ma:rk ~8578 trade-names "Termamyl"* and "Maxamyl"*, respectively.
An organic solvent is preferably used in combination with water to serve as the solvent for the liquid detergent composition. The preferred organic solvent is a lower alkanol of 1 to 4 carbon atoms having from 1 to 3 hydroxy groups, preferably 1 or 2. The lower alkanol is most preferably ethanol or a mixture of ethanol and isopropanol, wlth lower monoalcohols such as propanol and butanol, and lower polyols of 2 to 3 carbon atoms such as ethylene glycol and propylene glycol being useful albeit less preferred. The use of primary, secondary and tertiary butanol or n-propanol as the lower alkanol is generally restrlcted to mixtures of same with ethanol, ethanol being preferably at least 80 to 90% of such mixtures. It is highly pxeferred to use ethanol as the sole alkanol and organic solvent. In mixtures of ethanol and iso-propanol it is preferred that ethanol be the major component, ethanol being usually from 60 to 90% of the mixture, preferably about 75% (i.e., in a 3:1 ratio). Of course, other mixtures of the various alkanols may be used, such as ethanol and ~0 propylene glyGol, and in such mixtures it is also preferred that ethanol he the majox component.

*Trade Mark - 8a -The compositions of the present invention contain one or more surface active agents selected from the group of anionic, nonionic, cationic, ampholytic and zwitterionic detergent com-pour;ds. The synthetic organic detergents employed in the practice of the invention may be any of a wide variety of such compounds which are well known and are described at length in the text Surface Active Agents, VolO II, by Schwartz, Perry and Berch, published in 1958 by Interscience Publishers.
The nonionic detergents are usually poly-lower alkoxylated lipophiles wherein the desired hydrophile-lipophile balance is obtained from addition of a hydrophilic poly-~ower alkoxy group to a lipophilic moiety. For the present composi-tions the nonionic detergent employed is preferably a poly-lower alkoxylated higher alkanol wherein the alkanol is of 10 to 18 carbon atoms and wherein the number o~ moles of lower alkylene oxide (of 2 or 3 carbon atoms) is from 3 to 12. Of such materials it is preferred to el~ploy those wherein the higher alkanol is a higher fatty alcohol of 11 or 12 to 15 carbon atoms and which contain from 5 to 8 or 5 to 9 lower alkoxy groups per mole. Preferably, the lower alkoxy is ethoxy but in some instances it may be desirably mixed with propoxy, the latter, il present, usually being a minor (less than 50%) constituent. ~xemplary of such compounds are those wherein the alkanol is of 12 to 15 carbon atom.s and which contain about 7 ethylene oxide ~Jroups per mole, e.g., Neodol~ 25-7 and Neodol 23-6.5, which products are made by Shell Chemical Company, Inc.
The former is a condensation product of a mixture of higher fatty alcohols averaging about 12 to 15 carbon atoms, with about 7 moles of ethylene oxide and the latter is a corresponding mixture wherein the carbon atom content of the higher fatty *Trade Mark g _ . . .

lZa~85~8 alcohol is 12 to 1~ and the number of ethylene oxide groups per mole averages about 6.5. The higher alcohols are primary alkanols.

- 9a -~' lZ~8578 Other examples of such detergents lnclude Tergitol~ 15-S-7 and Tergitol 15-S-9, both of whlch are linear secondary alcohol ethoxy-lates made by Union Carbide Corporation. The former-is a mixed ethoxylation product of an 11 to 15 carbon atom linear secondary alkanol with seven moles of ethylene oxlde and the latter ls a similar product but with nine moles of ethylene oxide being reacted.
Also useful in the present compositions are higher molecular welght nonionlcs, such as Neodol 45-11, whlch are similar ethylene oxlde condensation products of higher fatty alcohols, with the higher fatty alcohol being of 14 to 15 carbon atoms and the number of ethylene oxide groups per mole being about 11. Such products are also made by Shell Chemical Company. Other useful nonionics are represented by Plurafac*B-26 (BASF Chemical Company), the reaction product of a higher llnear alcohol and a mlxture of ethylene and propylene oxides.
In the preferred poly-lower alkoxylated higher alkanol~, the best balance o~ hydrophllic and llpophilic moieties are obtained when the number of lower alkoxies are from about 40~ to 100~ of the number of carbon atoms in the higher alcohol, preferably 40 to 6 ~ thereof. The nonionlc detergent is preferably comprised of at least 50~ of the preferred ethoxylated alkanols. Higher molecu-lar weight alkQnols ~nd various other normally solid nonionlc detergent compounds~and ~urfactants may contribute to gelatlon of the liquld detereent composition and consequently~ are normally omltted or limited in quantity in the present compositions, al-though minor proportions thereof may be employed for thelr cleaning properties, etc. With re~pect to both preferred and ~ess preferred nonionlc detergents, the alkyl groups present therein are preferably linear although a mlnor degree of slight branchlng may be tolerated, ~uch as at a carbon next to or two carbons removed rrom the ter-minal carbon Or the straight chain and away from the ethoxy chaln *Trade Mark . . .

lZ~8578 with the proviso that such branched alkyl i~ no more than three carbons in length. Normally the proportion of carbon atoms in such a branced conflguration will be mlnor, rarely exceeding 20%
o~ the total carbon atom content of the alkyl. ~imilarly, although linear alkyls whlch are terminally ~oined to the ethylene oxlde chains are hlghly preferred and are con~idered to result in the optimum combination of detergency, biodegradabllity and non~gelling characterlstics, medial or secondary ~oinder to the ethylene oxlde in the chain may occur. In such instance, lt is usually in only a minor proportion o~ such alkyls, generally less than 20% but as i~ in the case of the aforementioned Tergitols, may be greater.
A1BO~ when propylene oxide i5 present in the lower alkylene oxide chaln, lt will usually be less than 20~ thereof and preferably le~s than lO~ thereo~
Wlth the nonlonic detergent, which 1B the ma~or ~ynthetic organic detergent ln the present liquid detergent compositions, there may be employed an anionic detergent The most preferred anionic detergent compounds are the higher (lO to 18 or 20 carbon atoms) alkyl benzene sulfonate salts wherein the alkyl group prefer-ably contains lO to 15 carbon atoms, most preferably belng a stralght chain alkyl radical of 12 or 13 carbon atoms. Preferably, such an alkyl benzene sulfonate has a high content of 3 (or higher) phenyl isomers and a correspondingly low content (usually well below 50%) of 2- (or lower) phenyl isomers; ln other words, the benzene rlng 18 preferably attached ln large part at the 3, 4, 5, 6 or 7 posl-tion o~ the alkyl group and the content of lsomers in which the benzene rlng is attached at the 1 or 2 positlon i5 correspondingly low. Typical ~lkyl benzene sulfonate surface active agents are described in U.S~ Patent 3,320,174. 0~ course, more hlghly branched alkyl benzene sulfonates may also be employed but usually are not preferred, due to their lack of biodegradablllty 1~8578 Other anionic ~etergents whlch are useful are the olefin sulfonate salts. Generally, the~e contain long chain alkenyl sulfonates or long chain hydroxyalkane ~ulfonates (wlth the OH
being on the carb~n atom whlch is not directly attached to the carbon atom bearing the -S03~ group~. The olefln sulfonate detergent usually comprises a mlxture o~ such types of compound~
in varying amounts, often together wlth long chain disulfonate~
or sulfate-~ulfonates. Such olefin sulfonate~ are described in many patentR~ such as U.S. Patent Nos. 2,061,618; 3,409,637;

3,332,880; 3,420,875; 3,428,654; 3,506,580; and Brltish Patent No. 1,129,158. The number of carbon atoms in the olefin sulfona~e is usually within the range of 10 to 25, more commonly 10 to 18 or 20, e.g., a mixture principally of C12, C14 and C16~ having an average of about 14 carbon atoms, or a mixture principally of C14, C16 and al8~ having an average of about 16 carbon atoms.
Another class of u~eful anionic detergent~ 1B that of the hlgher paraffin sulfonates These may be primary paraffin sul-fonates made by reactlng long chain alpha-olefins and bisulflte~, e.g., sodium bisulfite, or paraffin sulfonates havlng the sulfonate groups di~tributed along the paraffln chaln, such as the products made by reacting a long chaln par~ffin wlth sulfur dioxlde and oxygen under ultravlolet light, followed by neutralization with sodlum hydroxlde or other ~ultable base (a8 in U.S Patents 2,503,280;
2,507,088; 3,260,741; 3,372,188; and German Patent 735,096). The para~fln sul~onate~ preferably contaln from 13 to 17 carbon atoms and wlll normally be the monosulfonate but lf deslred, may be dl-, trl- or hlgher sulfonates. Typically, the dl- and polysulfonates wlll be employed ln admlxture wlth a corresponding mono~ulfonate, for example, a~ a mixture Or mono- and disulfonates containlng up to about 30% of the dlsulfonate. The hydrocarbon ~ubstltuent thereof will preferably be linear but if desired, branched chaln paraffin lZ~85'-~8 sulfonates can be employed, although they are not as good with respect to biodegradabilityr Other suitable anionlc detergents are sulfated ethoxylated higher fatty alcohols of the formula RO(C2H40)mS03M, wherein R
i~ a fatty alkyl of from 10 to 18 or 20 carbon atoms, m is from 2 to 6 or 8 (preferably having a value from about 1/5 to 1/2 th~ number of carbon atoms in R) and M is a solubilizing salt-formlng catlon, such as an alkali metal3 ammonium, lower alkyl amino or lower alkanolamino, or a higher alkyl benzene sulfonate wherein the higher alkyl i~ of 10 to 15 carbon atoms. As i~
the case with the preferred nonionlc detergent, it will be pre-ferred ~or the alkyl in the anionic alkoxylate detergent to be a mixture o~ di~ferent chain length~, such as 11, 12, 13, 14 and 15 carbon atom chains or 12 and 13 carbon atom chalns, rather than all of one chain length.
Ethylene oxide is the preferred lower alkylene oxide of the anlonlc alkoxylate detergent, as it is with the nonionic detergent, and the proportion thereo~ ln the polyethoxylated higher alkanol sulPate ls preferably 2 to 5 molec of ethylene oxide group~
present per mole of anionic detergent, with three moles being most pre~erred, especlally whén the higher alkanol 18 of 11 or 12 to 15 carbon atoms. To malntain the desired hydrophile-lipo-phile balance, when the carbon atom content o~ the alkyl chain is ln the lower portion o~ the 10 to 18 carbon atom range, the ethylene oxide content of the detergent may be reduced to about two moles per mole whereas when the higher alkanol ls of 16 to 18 csrbon atoms, in the higher part of the range, the number o~ ethylene oxide groups may be lncreased to 4 or 5 and in some cases to as high as 8 or 9. Slmilarly, the salt-formlng catlon may be altered to ob-tain the best solubility. It may be any suitably solubilizing metal or radical but will most frequently be alkali metal, e.g., lZ~38578 sodlum, or ammonium. If lower alkylamine or alkanolamine groups are ut~llzed the alkyls and alkanols will usually contain from l to 4 carbon atoms-and the amines and alkanolamines may be mono-, di- and tri-substituted, as in monoethanolamlne, dlisopropanol-amine and trimethylamine.
The poly-lower alkoxy higher alk-anol sulfates may~be employed in place of or ~n comblnation wit~h other preferred anionic detergents such as the higher alkyl benzene sulfohates to supplement the nonionic detergent in the present liquld deter-gent compositions. A preferred polyethoxylated alcohol sulfate detergent is av~ilable from Shell Chemical Company and ls marketed as Neodol 25-3S.
Examples of the hlgher alcohol polyethenoxy sulfates whlch may be employed ln the llquid detergent composltlons of the lnvention lnclude: mlxed Cl2 15 normal or prlmary alkyl tri-ethenoxy sulfate, sodlum salt; myristyl triethenoxy sulfate, pota~slum salt; n-decyl diethenoxy sulfate, dlethanolamine salt, lauryl diethenoxy sulfate, ammonium salt; palmityl tetraethenoxy sulfate, sodium salt; mixed Cl4 15 normal primary alkyl mixed tri- and tetra-ethenoxy sulfate, sodium salt; stearyl penta-ethenoxy sul~ate, trimethylamlne salt; and mixed ClO l~ normal primary alkyl triethenoxy sulfate, potassium salt, other useful anionlc detergents include the higher acyl sarcosinates, e.g" sodium N-lauroyl sarcoslnate; hlgher fatty ~lcohol sulfates, such as sodium lauryl sulfate and sodlum tallow alcohol sulfate; sulfated oils; sulfate~ of mono- or diglycerides of higher fatty acids, e.g., stearic monoglycerlde monosulfate;
although, of these, the sodium higher alcohol sul~ates ha~e been found to be inferior to the polyethoxylated sulfate~ ln detergency;
aromatlc poly(lower alkenoxy) ether ~ulfateE, such as the sulfates of the conden8ation products of ethylene oxide and nonyl phenol lZ~1~8578 (usually havlng 1 to 20 oxyethylene groups per molecule, prefer-ably 2 to 12); polyethoxy higher alcohol sulfates and alkyl phenol polyethoxy sulfates having a lower alkoxy (of 1 to 4 carbon atom~, e.g., methoxy) substituent on a carbon close to that carrying the sulfate group, such as monomethyl ether monosulfate of a long chain vicinal glycol, e.g., mixture of vicinal alkane diols of 16 to 20 carbon atoms in a straight chain; acyl esters of isethlonic acid, e.g~, oleyl isethionates; acyl N-methyl taurides, e.g., potas~ium N-methyl lauroyl or oleyl taurides; higher alkyl phenyl polyethoxy sulfonates; higher alkyl phenyl dlsulfonates, e.g.~ pentadecyl phenyl disulfonate; and higher fatty acid soaps, e.g., mixed coco-nut oil and tallow ~oaps in a 1:4 ratio.
Among the aforementloned types of anionic detergents, the sul~ates and sul~onates are generally preferred but the corresponding organic phosphates and phosphonates may also be employed when their contents of pho~phorus are not obJectlonable. Generally, the water ~oluble anionic synthetic organic detergent, (lncluding soaps), as was prevlously indicated, are salts of alkali metal catlons, such as potassium, lithium, and especially sodium, although salts of ammonium and substituted ~mmonium cations, such as those previously described, e.g , trlethanolamine, triisopropylamine, may be used too, In the above exempllfications of water-~oluble anionlc deter-gent lt should be considered that the sodium, potas~iu~, ammonium and ~lkanolammonium salts are indivldually recited for each detergent Ampholytic detergents may be employed ln the present compo-sltlons ln minor proportlons ln replacement of the anlonic deter-gent or a part thereof or in replacement of part of the nonionic detergent. Ampholytic detergents include the hlgher fatty carboxy-lates, phosphates, sulfate~ or sulfonates whlch contain a cationic ~ubstltuent such a~ an amino group, which may be quaternized, e.g., with a lower alkyl group, or chaln extended at the amino group by 126~8S78 condensation with a lower alkylene oxlde, e g., ethylene oxlde.
Generally the compositions containing such ampholytic or cationlc detergents will not be as e~fective and may have a greater tendency to gel or thicken on standing. Therefore they are often avoided.
However, if such properties are unob~ectionable, minor proportlons of ampholytics such as Miranol C2M, sold by Miranol Chemlcal Company, or Deriphat 151* a ~odium N-coco betaamine propionate, sold by General Mills, Inc., may be utilized. A cationic deter-gent that may sometimes be useful is distearyl dimethyl ammonium chloride (it has fabric softening activity) and the higher fatty amine oxides, such as bist2-hydroxyethyl) octadecyl amine oxide.
The viscosity control agent utilized to maintain the desired viscoslty of the liquld detergent composltlon, prevent gelatlon at low temperatures and allow a reduction ln lower alkanol solvent content is preferably a water soluble formate. Sodium formate is preferred but alkali metal formates rnay be utllized, e.g., potasslum formate and varlous other water soluble formates, includlng formic acid, which may be added to the liquid detergent composltion whereln it dissolves, lonizes and/or reacts to produce essentially the same type of llquid detergent as results from the addltion of the alkali metal formate ~n salt ~orm. Other formates ~hat may be employed are those of water soluble cntions, such as pr~viouslY dc-scribed as salt-formin~ cations for the anlonic detergents. Althour;h i~ is preferred to employ the formate viscosity control agent, lt has been found that varlous salts of dibasic acids can also be success-~ully used, among whlch the best appears to be disodium adipate, referred to herein as sodium adipate. Other salts o~ dibasic aclds of the formula (CH2)n(COOH)2 where n ls 1 to 6, may also be employ~d *Trade Mark 12~)8578 and in some instances the salts of mono-unsaturated acids of the same chain lengths and configurations may be u~ed. However, it is highly pre~erred to utilize the saturated aliphatic 6traight chain termin-ally carboxylated compounds. It is more preferable to employ those wherein n ls 3 to 5, most preferably 4, and wherein the acid ls fully neutralized, but the acid salts may also be used.
Among the dibasic acids that may be employed, either as the mono- or disalts, are malonicg succinic, glutaric, adipic and plmelic acids An unsaturated dibasic acid, maleic acid, can also be used, at least in part. The acids may be employed without prior neutra-lization or may be used as their salts, such as di~odium malonate, monopotassium succinate, di-triethanolamine glutarate, disodium adipate and monosodium pimelate.
To assist in solubilizing the detergents and optical bright-eners which may be present in the liquid detergent compositlons, a small proportion of alkaline material or a mlxture of such materials is often included in the present formulations. Sultable alkaline materials include mono-, di- and trialkanolamines, alkyl amlnes, ammonium hydroxides. Of these, the preferred materials are -the alkanolamines, preferably the trialkanolamlnes and of these, especially trlethanolamine. The pH of the ~Inal liquid detergent composltion containlng such a basic material will usually be neutral or slightly basic. Satisfactory pH ranges are from 7 to 10, pre~erably from about 7 5 to 9, and most preferably from about 7.5 to 8.5.
The optical fluorescent brighteners or whiteners employed in the liquid detergent compositions are important constituents of modern detergent compositlons which give washed laundry and materials a bright appearance 80 that the laundry is not only clean but also appears clean. Although it is possible to utilize a slngle bri~htener for a specific intended purpose in the present liquid detergent it is generally desirable to employ mixtures of brighteners which will have good brightening effects on cotton, nylons, polyesters and blends of such materials and which are also bleach stable. A good description of such types of optical brighter,ers is given in the article "The Requirements of Present Day Detergent Fluorescent Whitening Agents" by A.E.
Siegrist, J. Am. Oil Chemists Soc., January 1978 (Vol. 55).
That article and United States Patent 3,812,041, issued May 21, 1974, contain detailed descriptions of a wide variety of suitable optical brighteners.
Among the brighteners that are useful in the present liquid detergent compositions are: Calcofluor* 5BM (American Cyanamid); Calcofluor White ALF (American Cyanamid); SOF* A-2001 (Ciba); CDW* (Hilton-Davis); Phorwite* R~H, Phorwi-te BBH and Phorwite BHC (~erona); CSL*, powder, acid (American Cyanamid);
FB 766* (Verona); Blancophor* PD (GAF); UNPA (Geigy); Tinopal*
RBS 200 (Geigy). I'he acid or "nonionic" forms of the bright-eners tend to be solubili~ed by alcohols of the present formulas, while the salts tend to be water soluble.
Adjuvants may be present in the liquid detergent compositio~ to glve it additional properti.es, either Eunctional or aes-thetic. Included among the useful adjuvants are soil suspending or anti-redopo~ition agents, such as polyvinyl a]cohol, sodium carboxymethy] cellulose, hydroxypropylmethyl cellulose; thickeners, e.g., gums, alginates, agar agar; Eoam improvers, e.g., Iauric myristic diethanolamide; Eoam destroyers, e.g., silicones; bactericides, e.g., tribromosalicylanilide, hexachlorophene; dyes; pigments (water dispersible); preserva-tives; ultraviolet absorbers; fabric soEteners; opacifying agents, e.g., polystyrene suspensions; and perfumes. Of course, such ma-terials will be selected for the *Trade Mark _ 1~ --lZ~i8578 properties desired in the fin~shed product and ts be compatible with the other constituents thereof. Other ad~uvants that may be employed are dihydric or trihydric lower alcohols which, in addition to being solvents and reducing the ~lash point of the product, can act as anti-freezing constituents and may improve compatibilities of the solvent system with particular product components. Among these compounds the most preferred group ln-cludes the lower polyols of 2 to 3 carbon atoms, e.g~, ethylene glycol, propylene glycol and glycerol, but the lower alkyl (Cl-C4) etheric derivatlve~ of such compounds, known as Cello-solves~, may also be employedO The proportions of such substit-utes for the lower alkanols will be limited, normally being held to no more than 20% oY the total alcohol content of the liquid detergent, Another category of useful additives are hydrotropes which serve to enhance the sol~bility in aqueous solutlon of components whlch otherwlse have llmited solubility in water. Useful hydro-tropes lnclude the alkall metal, ammonium and ethanolamine salts of the following acids: (1) aryl sulfonic acids, such as benzene sulfonic acid and Cl-C3 alkyl-substltuted benzene sulfonlc acids, e.g., toluene sulronlc acld and xylene sulfonlc acid; and (2) Cs-C6 alkyl sulfuric aclds, such as hexyl sulfuric acld.
The proportions of the varlous componentR o~ the present llquld detergent compositions are important for the manufacture o~ a uni-form product of deslrable ~lscosity and acceptable heavy duty laundering action whlch does not gel at low temperatures or upon standing ln an open contalner at room temperature.
To promote solublllty of the fluorescent brlghteners and other constituents in the detergent composltlon and to make a clear, homogeneous and readily pourable llquld product, from 10 to 60~
o~ the total liquid detergent concentrate should be nonionlc deter-gent. Preferably, especially when an anionlc detergent 18 present 12~8578 in the liquid product, the proportion of the nonionic deter-gent is from 20 to 40% and more preferably it is 30 to 40~, with the best formula known at the present tlme including about 32~. The proportion of anionic detergent will usually be in the range of 3 to 15%, preferably 4 to 12% and most preferably 6 to 10% with the best formula known at the present including about 7% thereof. The ratio of total nonionic deter-gent to anionic detergent will normally be from 15:1 to 1:1, with ~:1 to 2:1 being preferred and 5:1 to 3:1 being most pre-ferred.
The lower alkanol in the llquid detergent composltions will generally be present in a sufficient proportlon to aid in dis-solving and/or stabilizing the various constituents in the final product. The proportlons of lower alkanol used will normally be ~rom about 3 to 15~, preferably 4 to 12%, more preferably 4 to 8% and at the present tlme mo~t preferably about 5%.
The vlscosity control agent utilized or a mixture of such agents will normally be from about 0.5~ to 5% of the final llquid detergent composltion, preferably about 0.5 to 3%, and most preferably about 1~.
The percentage of water, the maln solvent ln the present compositlons,will u~ually be ~rom about 25 to 85%, pre~erably 35 to 65~ and mo~t preferably ~rom about 40 to 55%, by weight, of the liquid composition. In the most preferred forMulations there wlll be about 45 to 50% water The content o~ the alkaline addltive, such as triethanolamine, in the liquid composition is usually from about 0.1 to 5% of the composltion and preferably 1 to 3~, by weight, thereof. The total proportion of optical brightener is normally from about 0 05 to 1.5%, preferably about 0.1 to 1% and most preferably about 0 2 to 0.5~

lZ~578 The liquid detergent compositions of the present invention, can be made by simple manufacturlng techniques. In a typical manufacturing method the optical brightener~ are slurried in the monohydric alcohol, after which water ls added to the slurry to-gether with a small amount of a base, ~uch as trlethanolamine, which help~ to partially dissolve the previously suspended material. Addition of the anionic detergent compound usually results ln the remainder of the brightener dissolving to make a clear solution. The viscoRity control agent 18 then added as the acid, acidic salt or completely neutralized salt, preferably the sodium or potassium salt, and agitation i~ continued until the solution becomes clarified, whlch may normally take about 5 to 10 minutes. At this polnt the principal detergent, the non-ionic, ls added along with a minor amount of acld for purpo~es o~
pH regulation, the pH belng generally ad~usted to a value at whlch the proteolytic enzyme used is most stable. This i8 followed by agitatlon of the solution and the addition of ad~uvants, such as, perfume and dye which give the product it~ final desired properties.
~he protease and cx-amyla~e enzyme preparations are then added to the solution and mlxed therewith a~ the final step in produclng the product liquid detergent compositlon. If de~ired the viscosity control additlve m~y be incorporated earlier in the procedure.
The above operQtions may be erfected at room temperature, although suitable temperatures within the range of 20 to 50C.
may be employed, a~ desired, with the provlso that when volatile materials, such a5 per~ume, are added, the temperature should be low enough 80 as to avoid ob~ectionable losses. The product ob-tained will usuQlly have a pH withln the range Or 7 to lOg and a den~ity within the range of from 0.9 to 1.1, preferably from 0.95 to 1.05. The vlsco~lty o~ the final product at 24C will be in the range o~ 60 to 150 centipoises, preferably from about 80 to 140 centipoises, and most preferably from about 115 to 135 centlpolses, according to measurements that are made with a Brookfield viscoslmeter at room temperature.

12~57~3 The present liquid compositions are efficient and easy to use. Compared to heavy duty laundry detergent powdersg much smaller volumes of the pre~ent liquid~ are employed to obtain comparable cleaning of soiled laundry. ~or example, using a typlcal preferred formulation o~ this lnvention, only about 60 grams or 1/4 cup of liquid is needed for a full tub of wash in a top-loading automatic washing machine in which the water vol-ume is 15 to 18 gallons (55 to 75 liters); and even less (about 1/2) i6 needed for front-loading mach~nes. Thus, the concentra-tion of the liquld detergent composition in the wash water is on the order of about 0.1%~ Usually, the proportion of the liquid composition in the wash solution will range from about 0.05 to 0.3%, preferably from 0.08 to 0 2% and most preferably from about 0.1 t~ 0.15%. The proportions of the various con~tituents of the liquid composltlon may vary accordingly Equlvalent re-sults can be obtained by using greater proportlons of a more dilute formulation but the greater quantity needed will requlre addltional packaging and will generally be less convenient for consumer use. Also, more hlghly diluted product~ wlll be more apt to freeze in cold weather, and may be more sub~ect to hydrolysls and chemlcal changes on storage.

iZ~85~8 Example 1 A liquid detergent composltion (containing no enzymes)~
designated as composition "A" was prepared at room temperature by mixing the following components in the ~tated proportions:

Component Weight Percent .
Ethoxylated C12-C15 32.0 primary alcohol (7 moles EO/mole alcohol) Sodium dodecyl benzene 7.0 sul~onate Triethanolamine 2,8 Ethanol 5~o Sodium formate 1.0 H2S04 (conc.) 0,7 Optlcal brlghteners(l) 0.27 Dye~2) 0.01 Perfume o.35 Water bal~nce (1) A mlxture of Phorwite RKH and Phorwlte BHC brlghtener~
manufactured by Verona.

(2) Polar Brllhant Blue (PBB) manufactured by Clba-~elgy.

~2~8578 Enzyme-contalnlng liquid detergent compo~ltlon~ B-U were formulated by addin3 various amounts of protease and alpha-amylase enzymes to the above-descrlbed composition A. The enzyme concentration in each of the detergent compositions is shown in Table ~ expre~sed in terms of percent o~ enzyme formulation based on the wei~ht of the composition. The protease enzyme employed was a liquid enzyme f~rmulation sol~ under the name "Alcalase" by Novo Indus5ries o~ Copenhagen, Denmark having a concentration o~ 2.5 Anson units per gram of enzymè preparation. The alpha-amylase en-zyme employed was a liquid enzyme ~ormulatio~ sold under the name "Tbrmamyl" by No~o Industries ha~ing a concentration of 120,000 Novo ~mylaæe units ~er gram of liquld enzyme preparation.

Test Procedure A total of 6 cotton ~watches, 3 ~tained with peef liver blood and 3 stalned with grass, were placed in each of 4 bucket~
o~ a Tergotometer vessel manufactured by U.S. Te~ting Company.
A serle~ of laundering tests were conducted uslng a different liquld detergent compositlon ~rom compositions A-U ln each bucket of the Tergotometer under the following test conditions:

Llquld detergent concentration 0.09%
Agltatlon lO0 rpm Agltatlon tlme lO minutes Water temperature 120F
Water hardness About 150 ppm as calclum carbonate At the end of the wash, the test swatches were rlnsed in tap water and then dried. The percent staln removal was measured by taking a reflectance readlng for each stalned test swatch prior to and after the washlng uslng a Gardner XL-20 Colorimeter, and the percent staln removal (% S.R.) was calculated as follows:

-24_ ~Z~8S78 S.R. = (Rd after washing) - (Rd before washir,g) (Rd before staining) - (Rd before washing) wherein "Rd before washing" represents the Rd value after staln-ing.
The values of percent stain removal calculated for each of the three test swatches havlng a common stain were averaged for each liquid detergent composltion tested. The results are shown in Table 1 ~rhich sets forth:the percent S~Rr for each of the li~uid detergent compositions tested (compositions A-U) and the enzyme concentration of such detergent compositions.

S~8 Table l Comparative Stain Removal wlth .
Enzyme-Containing Detergent Compositions .
Weight %(l) Weight %
- Composition Proteaæe ~Amylase(2) ~ Stain Removal Beef liver blood Grass A Q~0 0,0 42.0 31.5 B 0.2 o.o 50.~ 37.6 ~ 0.4 o.o 52.8 36.7 D o.6 o.o 53.9 36 8 E o.8 O.G 55.5 36 1 F 0,0 0.2 44.2 37.6 G 0.2 0.2 55.3 42.4 H 0.4 0.2 58.4 44.8 I o.6 0.2 ~o 6 44 5 J O.B 0.2 60 5 44 1 K 0.0 o,4 47.1 ~8.3 L 0,2 o,4 56.2 43 ~
M oO4 o,4 58.6 45 0 N 0.6 o,4 63.3 44.8 o o.8 o,4 63.2 45,~
p o.o o.6 47,7 37.6 0,2 o.6 55.4 41.3 o,4 o.6 57.5 42.1 S 1 0,~ o.6 60.9 43~7 T o.8 o.6 62.0 44.5 u o.o o~8 47,7 36.5 .

(1) The proteolytic activity of Alcala~e 1B 2.5 Anson u~lts per gram.
Thus, a concentration of, for example, 0,2% of Alcalase ln the llquid detergent composltlon corresponds to a protea~e enzyme actlvlty of 0.5 An~on unit6 (0,2 x 2,5) per lO0 grams of detergent composltlon.

(2) The amylolytic actlvlty of Termamyl i~ 120,000 Novo amyla~e unlts per gram~ Thus, a concentratlon of 0.2% Termamyl ln the llquid detergent compositlon corresponds to an 0~-amylase enzyme actlvity of 24,000 Novo amylase unlts (0.2 x 120,000) per 100 grams of detergent composltlon, _26-~12~3S'78 As indicated in Table 1, the percent stain removal (S.R.) achieved with cQmposition A represents the S.R. achieved in the`absence of en~ymes in the detergent composition. Referring to the S.R. data for the beef liver blood stain, a comparison of the S.R. achleved with compositions F, K, P and U, all of which contain amylase enzyme, but no protease and are therefore not in accordance with the invention, shows that composition P contain~
ing o.6 wt. % ~-~mylase provided the maximum improvement in S.R.
(47.7%) achievable with amylase enzyme, i~e., an increase of about 507% relative to the S.R. value of 42.0% for the enzyme-free compo-sition A. Slmilarly, a comparison of the S.R. achieved with compo-sitions B, C, D and E, all of which contain ~rotease enzyme, but no amy~ase, shows that composition E containing o.8% protease provided the maxlmum ~mprovement in S.R. (55.5%) with protease enzyme, i.e., an increase of about 13.5% relatlve to the 42% S R achieved with enzyme-free composltion A.
The ~ynerglstic interactlon of protea~e and amylase enzymes for the removal o~ protelnaceous 6tains i~ evident from Table l.
Thu~, ~or example, composltlon G eontalnlng 0.2 wt. % protease and 0.2 wt. % amylase enzymes (corresponding to an amylase/protea6e enzyme activlty ratlo of 24,000 Novo amylase unlts per 0.5 Anson units) provided nearly the same improvernent ln S.R (relative to enzyme-~ree composition A) as was achieved with o.8 wt. % protease ln composltlon E. From an economlc standpoint, the use of compo-sition G containlng a mixture Or enzymes ln accordance with the lnvention clearly represents a substantial reductlon ln the requlrement for the relatively expensive protea~e enzymeJ a~
compared to compositlon E.
The highest percentage of stain removal wa~ achieved wlth composltion N. Speclflcally, the comblnatlon of o.6 wt ~ protease and 0 4 wt. % amylase ln compo6itlon N provlded a greater than 21%
lncrea~e in the percent S R. for the blood 6tain relatlve to enzyme-_27-lZC)8S~78 free composition A. Thus, the 63.3~ S.R. achieved with composition N is significantly higher than the maximum S.R, that could be achieved with deter~ent compositions containing protease enzyme in the absence of C~-Amylase. The amylase/protease enzyme activity ratio of such composition N is 48,ooo Novo amylase unlts per 1.5 Anson unlts.
The synergistic interaction of protease and alp~a-amylase enzymes is likewise evident in the S.R. data for the grass stain. Thus, for example, composition H containing 0,2%
amylase and 0.4% protease enzymes provided a substantially higher S.R, than could be achieved with detergent compositions containing either protease or amyla~e as individual enzymes in the composition.

Claims (13)

WHAT IS CLAIMED IS:

1. An enzyme-containing liquid detergent-composition comprising:
(a) from about 5 to about 75%, by weight, of one or more detergent surface active agents selected from the group consisting of anionic, nonionic, cationic, ampholytic and zwitterionic detergent compounds;
(b) from about 25 to 85% water; and (c) an enzyme mixture consisting essentially of an alka-line protease enzyme and an .alpha.-amylase enzyme in rela-tive proportions such that the ratio of the respective enzyme activities in said mixture is from about 4,000 to about 80,000 Novo amylase units of .alpha.-amylase per Anson unit of protease, said protease being present in an amount to provide from about 0.25 to about 2.5 Anson units per 100 grams of detergent composition.

2. A detergent composition according to claim 1 wherein the ratio of the enzyme activities in said enzyme mixture is from about 15,000 to about 40,000 Novo amylase units of .alpha.-amylase per Anson unit of protease, and said protease is present in an amount to provide from about 0.5 to about 2.0 Anson units per 100 grams of detergent composition.

3. A detergent composition according to claim 2 wherein said ratio of enzyme activities is from about 30,000 to about 40,000 Novo amylase units of .alpha.-amylase per Anson unit of pro-tease.

4. A detergent composition according to claim 1 wherein said detergent surface active agents consist essentially of from about 20% to about 40%, by weight, of a water-soluble C2-C3 alkoxylated C10-C18 alkanol nonionic detergent and from about 4 to 12%, by weight, of a water-soluble salt of a C10-C15 alkyl benzene sulfonate anionic detergent; and which con-tains, in addition, from about 3 to 15%, by weight, of a lower alkanol selected from the group consisting of a lower monoalcohol having l to 4 carbon atoms, a lower polyol having 2 to 3 carbon atoms and mixtures thereof

5. A detergent composition according to claim 1 which contains, in addition, from about 0.5 to 5%, by weight, of a viscosity control agent selected from the group consisting of water-soluble formate salts and dibasic acids of the formula (CH2)n(CooH)2 wherein n is 1 to 6.

6. An enzyme-containing liquid detergent composition consisting essentially of (a) from about 20 to about 40%, by weight, of a nonionic detergent compound consisting essentially of a water-soluble C2-C3 alkoxylated C10-C18 alkanol;
(b) from about 4 to about 12%, by weight, of an anionic detergent compound consisting essentially of a water-soluble salt of a C10-C15 alkyl benzene sulfonate;
(c) from about 3 to 15%, by weight, of a lower alkanol selected from the group consisting of a lower mono-alcohol having 1 to 4 carbon atoms, a lower polyol having 2 to 3 carbon atoms and mixtures thereof;
(d) from about 0.5 to 5%, by weight, of a viscosity control agent consisting essentially of a water-soluble formate salt;
(e) from about 35 to 65%, by weight, water; and (f) an enzyme mixture consisting essentially of an alkaline protease enzyme and an ?-amylase enzyme in relative pro-portions such that the ratio of the respective enzyme activities in said mixture is from about 4,000 to about 80,000 Novo amylase units of ?-amylase per Anson unit of protease, said protease being present in an amount to provide from about 0.25 to about 2.5 Anson units per 100 grams of deter-gent composition.

7. A detergent composition according to claim 6 which, in addition, contains from 0.1 to 5%, by weight, of an alkanol-amine.

8. A detergent composition according to claim 6 wherein the ratio of enzyme activities in said enzyme mixture is from about 15,000 to about 40,000 Novo amylase units of ?-amylase per Anson unit of protease, and said protease is present in an amount to provide from about 0.5 to about 2.0 Anson units per 100 grams of detergent composition.

9. A detergent composition according to claim 8 wherein said ratio of enzyme activities is from about 30,000 to about 40,000 Novo amylase units of ?-amylase per Anson unit of protease.

10. A detergent composition according to claim 6 wherein said nonionic detergent compound is a polyethoxylated C12-C15 alkanol having from 3 to 12 ethylene oxide groups per mole;
said anionic detergent is a C12 or C13 alkyl benzene sulfonate;
said lower alkanol is ethanol or a mixture of ethanol and iso-propanol; and said viscosity control agent is sodium formate.

11. A method of laundering comprising contacting the stained and/or soiled fabrics to be laundered with an enzyme-containing liquid detergent composition comprising:
(a) from about 5 to about 75%, by weight, of one or more detergent surface active agents selected from the group consisting of anionic, nonionic, cationic, ampholytic and zwitterionic detergent compounds;
(b) from about 25 to 85% water; and (c) an enzyme mixture consisting essentially of an alka-line protease enzyme and an ?-amylase enzyme in rela-tive proportions such that the ratio of the respective enzyme activities in said mixture is from about 4,000 to about 80,000 Novo amylase units of ?-amylase per Anson unit of protease, said protease being present in an amount to provide from about 0.25 to about 2.5 Anson units per 100 grams of detergent composition.

12. A method according to claim 11 wherein the ratio of enzyme activities in said enzyme mixture is from about 15,000 to about 40,000 Novo amylase units of ?-amylase per Anson unit of protease, and said protease is present in an amount to provide from about 0.5 to about 2.0 Anson units per 100 grams of detergent composition.

13. A method according to claim 11 wherein said liquid detergent composition consists essentially of (a) from about 20 to about 40%, by weight, of a nonionic detergent compound consisting essentially of a water-soluble C2-C3 alkoxylated C10-C18 alkanol;
(b) from about 4 to about 12%, by weight, of an anionic detergent compound consisting essentially of a water-soluble salt of a C10-C15 alkyl benzene sulfonate;
(c) from about 3 to 15%, by weight, of a lower alkanol selected from the group consisting of a lower mono-alcohol having 1 to 4 carbon atoms, a lower polyol having 2 to 3 carbon atoms and mixtures thereof;
(d) from about 0.5 to 5%, by weight, of a viscosity control agent consisting essentially of a water-soluble formate salt;
(e) from about 35 to 65%, by weight, water; and (f) an enzyme mixture consisting essentially of an alkaline protease enzyme and an ?-amylase enzyme in relative pro-portions such that the ratio of the respective enzyme activities in said mixture is from about 4,000 to about 80,000 Novo amylase units of ?-amylase per Anson unit of protease, said protease being present in an amount to provide from about 0.25 to about 2.5 Anson units per 100 grams of detergent composition.