Note: Descriptions are shown in the official language in which they were submitted.
CA 02231460 1998-O1-OS
WO 97/05227 PCT/US96/12052
AN ANIONIC STABILIZED ENZYME-BASED
CLEAN-IN-PLACE SYSTEM
FIELD OF THE INVENTION
This invention relates to an enzyme-based cleaning system for use in
clean-in-place operations to remove protein based soils.
BACKGROUND OF THE INVENTION
1o Proteolytic enzymes have been used extensively in alkaline detergent
formulations to aid in the removal of protein-based stains which tend to
adhere to textile surfaces. The most common type of formulation, which
employs enzymes of this nature, are solid based detergents. The enzyme in
its solid stable form is mixed with alkaline solid detergent formulations
~5 containing the usual surfactants, anti-redeposition agents, water hardness
control agents, other chelators and the like. Solid enzymes in this type of
formulation have very reliable stability over extended periods. Hence, the
solid enzyme based detergent products can be packaged and stored for
extended periods before use.
2 o There are, however, many cleaning situations where an enzyme based
alkaline detergent is preferably in liquid form. Such liquid forms of
detergents are more readily diluted and dispersed in the cleaning
formulations. They are particularly useful in cleaning of textiles because
they may be applied in concentrated liquid form before the normal cleaning
25 process. Considerable effort and interest has been pursued in formulating
enzyme based cleaning systems which are in a liquid form. There is,
however, a significant difficulty in maintaining enzyme activity in liquid
based detergents. It is well known that cationic and the most common
anionic surfactants attack enzymes, breaking them down and rendering them
CA 02231460 1998-O1-OS
WO 97/05227 PCT/US96/12052
2
non-active. It is generally understood, however, that nonionic surfactants
carf be used in conjunction with enzymes and not appreciably affect the
activity of the enzyme in a liquid formulation. It is also generally
understood that the presence of water in a liquid enzyme formulation causes
s degradation of the enzymes by self-digestion which is commonly referred to
as autolysis. The presence of oxygen in the liquid formulation can also
present a significant problem because oxygen can denature the enzymes.
The presence of oxygen is normally controlled by the use of antioxidants.
However, the introduction of antioxidants to the composition can over time
cause the pH of the composition to drop well below the normal alkaline pH
range in which the enzymes are active. By virtue of the pH dropping, the
enzymes become inactive.
However, in view of the significant interest in liquid detergents
containing enzymes, several approaches have been taken to stabilize the
~5 enzyme composition so that the enzymes are active in use.
Enzyme detergent formulations have also become useful in clean-in-
place operations where it is desired to remove protein-based deposits on
various types of processing equipment such as dairy equipment. Quite often
in dairy processing, high temperatures are used which results in the deposit
2 0 of difficult to remove soils on internal surfaces of processing equipment.
Removal is normally accomplished by the use of highly alkaline or highly
acidic compositions. Such compositions, although successful in removing
deposited materials, are somewhat hazardous to use and must be neutralized
before being discarded. Furthermore, the highly alkaline or acidic cleaning
2 s compositions are very corrosive and can attack components of the
processing
equipment. Alternatives have therefore been sought.
United States patent 4,212,761 describes a composition which is
useful in cleaning processing equipment in dairy production. The enzyme is
particularly useful in dissolving milkstone deposits and other dairy deposits
3 0 on interior surfaces of the processing equipment. The composition is very
CA 02231460 1998-O1-OS
WO 97/05227 PCT/US96/12052
3
useful for a clean-in-place process; however, the composition is supplied in
solid form and dissolved on site in water before use. Such solid composition
consists essentially of a nonionic or anionic detergent, sodium carbonate or
sodium bicarbonate and an alkaline protease. In solid form, the enzyme is
s stable even in the presence of the anionic detergent material. The nonionic
or anionic detergent material is employed solely to act as a detergent to
facilitate the cleaning action where it is thought that any suitable nonionic
or
anionic detergent material may be used. The preferred form of enzyme is a
proteolytic enzyme which is capable of breaking down the deposited milk
1o solids, particularly in the form of milkstone. Having to make up the
composition on site significantly complicates the administration of the
cleaning composition in a clean-in-place operation. Liquid formulations are
far superior in this regard since they may be stored in drums and
automatically dispensed as needed during the clean-in-place operation.
i5 United States patents 4,243,543 and 5,064,561 recognize the
advantages of liquid compositions for clean-in-place systems and describe
two-part compositions which are kept separate until they are combined and
diluted for use in the clean-in-place operation. United States patent
4,243,543 recognizes the significant problem in stabilizing enzymes in an
2 o aqueous system. In order to achieve such stabilization in an aqueous
solution which may contain up to the perceived maximum of 30 °b by
weight
water, an antioxidant is used to enhance stability of the enzyme in the
aqueous system. The enzyme-containing part of the composition comprises
the proteolytic enzyme, an anionic and/or nonionic surfactant and the
2 s antioxidant with the balance being water. Because of the use of the
antioxidant, the aqueous solution is not pH stable. The antioxidant will
cause the pH of the solution to drop, thereby rendering the enzyme inactive
over time. In order to maintain the pH of the composition in the desired
range of 5.2 to 9 and avoid downward pH shifts, a buffering amount of a
3 o weak base is included to stabilize pH. The buffer may be any of the well-'
CA 02231460 1998-O1-OS
WO 97/05227 PCT/L1S96/12052
4
known compositions capable of stabilizing pH, such as carbonates which
have a pKa within the range of about 6 to 12. In addition to further stabilize
the enzyme in this composition, a water soluble polyol containing from 2 to
6 hydroxyl groups and having a molecular weight of less than S00 is used to a
s achieve a stable composition for storage. The second component for this
two-part cleaning system comprises a chelant or sequestering agent for
sequestering the alkaline earth metal cations in the plant water used to
dilute
the two parts when combined during the clean-in-place operation.
United States patent 5,064,561 discloses a two-part clean-in-place
system which provides for stability of the enzyme in the second concentrated
solution by ensuring that the concentrate is substantially absent of free
water
and the enzyme is combined with a carrier such as alcohols, surfactants,
polyols, glycols and mixtures thereof. The first concentrate comprises a
hydroxide- based alkaline material, a defoamer, a solubilizer or emulsifier
is and a water hardness control additive. The defoamer is used to control
foaming as caused by the presence of the protease in the second concentrate.
It is suggested, however, that the defoamer is optional if a liquid form of
the
enzyme is used in the second concentrated solution. However_ the ~~nn~
concentrate still requires that the liquid form of the enzyme be absent of any
2 o free water as it would apply to both the source of enzyme and carrier.
Although this is a successful two-part clean-in-place system, it is difficult
to
supply the second concentrate containing the enzyme which is essentially
absent of any free water.
It would therefore be beneficial if a two-part clean-in-place system
2 s particularly for use in cleaning dairy equipment could be made where water
is present in the second concentrate containing the enzyme and where
stability of the enzyme in the concentrate is maintained to ensure proper
shelf life.
CA 02231460 1998-O1-OS
WO 97/05227 PCTlCJS96/12052
SUMfMAI~tY OF THE INVENTION
- The composition in accordance with this invention provides two
- concentrates containing a minimum of components which surprisingly
provide very effective cleaning for clean-in-place operation. The second
5 concentrate now includes water while maintaining acceptable enzyme
activity.
In accordance with an aspect of the invention, a two-part enzyme
based cleaning system comprises the first and second liquid concentrates
stored in separate containers where the concentrates are used in preparing a
1o dilute use solution.
A. The first concentrate consists of:
i) I.75 to 7.5 percent by weight of a source of alkalinity
selected from sources of hydroxide-based alkaline
compositions;
~5 ii) 1 to 16 percent by weight of a water conditioner selected
from the group consisting of polyacrylic acids and
polyphosphates; and
iii) balance water;
B. The second concentrate consists of:
2 o i) 5 to 45 percent by weight of an enzyme stabilizing
blend of an alkali salt of a (C6 - C12) fatty acid and a
linear (C$ - Cl$) polyoxyalkylene alcohol;
ii) an effective amount of a proteolytic enzyme;
iii) optionally, an enzyme compatible non-aqueous liquid
2 5 polyol filler; and
iv) balance water.
DETAILED DESCRIPTION OF TFiE PREFERRED EMBODIIVViENTS
Although the two-part clean-in-place composition, in accordance with
this invention, is particularly useful in cleaning of dairy processing
3 o equipment particularly as a composition used in a clean-in-place system,
it is
CA 02231460 1998-O1-OS
WO 97/05227 PCT/US96/12052
6
understood that the composition may also be used in other cleaning
operations where enzyme activity is desired, such as in laundry
formulations, surface cleaning formulations and the like. Examples of
surface cleaning include removal from process equipment surfaces of ,
brewing wont, food soils from processed foods, beverage soils (e.g., fruit
juices, orange juice, juice drinks and beverages), blood in meat plants, milk
based soils commonly found in the dairy industry, such as ice cream, milk,
flavored milk, cream, buttermilk and the like and pharmaceutical products.
The composition contains a minimum of components, yet surprisingly
1o achieves cleaning activity comparable to the far more complex mufti-
additive
systems of the prior art, such as described in United States patents
4,243,543 and 5,064,561 and other forms of highly alkaline cleaners. It is
understood that other components for purposes other than achieving
enzymatic attack of proteinaceous materials may be added to the
composition.
The essential aspect of the invention resides in the provision of a first
concentrate which contains only two active ingredients and a second
concentrate which contains only two different active ingredients. In both
concentrates, the active ingredients are solubilized in water to provide the
2 o desired liquid concentrates. It has been found that with the ingredients
used
in the second concentrate, acceptable enzyme stability is achieved even
though the active ingredients employed would, as suggested by the prior art,
presumably break down the enzyme and render the enzyme inactive.
However, surprisingly, the selected components of the blend which forms
2 5 the first ingredient of the second concentrate stabilizes the enzyme and
ensures its activity when used with the first concentrate to provide a diluted
solution effective for use in a clean-in-place operation. In circumstances
where very high levels of enzyme dilution are required in the second
concentrate, enzyme compatible non-aqueous fillers may be used.
CA 02231460 1998-O1-OS
WO 97/05227 PCTIUS96/12052
7
As is generally understood, enzyme activity can vary greatly based on
the-source of the enzyme either extracted from natural sources or isolated
from a culture of bacteria which under appropriate conditions manufacture
the enzyme. The main objective is to provide in the second concentrate
sufficient active enzyme which, when provided in the use dilution, is able to
digest the proteinaceous soils and provide the desired cleaning action.
Hence, depending upon the source of the enzyme, usually by suitable trial
and error, a sufficient amount is incorporated in the concentrate to provide
the desired cleaning. It has been found that the second concentrate, which
to contains the enzyme, is sufficiently stabilized by the blend of ingredients
that
after considerable storage time, sufficient activity remains to effect the
desired cleaning. For example, it has been found that storage of the second
concentrate at normal storage temperatures for up to three months does not
greatly affect the enzyme activity. Even storage at these temperatures of up
~5 to six months still provide a sufficiently active enzyme to effect the
desired
cleaning. The activity of the enzyme is such that very little of the enzyme is
required in the use solution. Hence if there is a falling off of activity in
the
second concentrate over greatly extended periods, that is well in excess of
six months, the amount of second concentrate used in the use solution may
2 o be slightly increased to ensure that there is still sufficient active
enzyme in
the use solution to achieve the desired cleaning effectiveness.
Furthermore, it has been found that the enzyme in combination with
the blend of materials in the second concentrate does not have a foaming
problem which was normally associated with the presence of proteinaceous
2 5 material. Hence defoamers and the like are not needed in the first
~ concentrate to deal with the proteinase material present in the second
concentrate. In view of the stabilizing effect in the second concentrate, it
has been found that antioxidants and consequent required buffers and the like
are not required in the composition. The first and second concentrates, in
3 o accordance with this invention, provide a cleaning system which includes
CA 02231460 1998-O1-OS
WO 97/05227 PCT/US96/12052
8
fewer ingredients and is therefore more cost effective for use in cleaning
operations.
In the second concentrate, the blend of active ingredients which
provides for the stability of the proteolytic enzyme, is a combination of an
alkali salt of a (C6 - Ci2) fatty acid and a linear (Ca - Cla )
polyoxyalkylenealcohols. The fatty acid is preferably Ca - Clo such as
octanoic acid, nonanoic acid and decanoic acid. The preferred alkali salts
thereof are potassium and sodium. The linear polyozyalkylene is considered
to be a nonionic with Ca to Cla carbon atoms in the linear alkyl chain, where
~o the chain terminating in alcohol, is usually either ethoxylated and/or
propoxylated. The components of the blend can be readily obtained from a
host of suppliers of anionic and nonionic surfactants. This blend of
components has been found to be compatible with the selected proteolytic
enzyme, such that when stored.in water is not attacked by the blend and
prevents autolysis in the water so that the enzyme activity is maintained
during a normal shelf life expectancy period.
The preferred enzyme is an endoproteinase of the serine type. The
effective amount of the enzyme in the concentrate is sufficient to provide the
desired degree of activity which is usually in excess of 85 qb of the original
2 o activity as previously described. The preferred enzyme is sold under the
trademark ESPERASE and may be obtained from Novo Industries of
Denmark. The enzyme is prepared by submerged fermentation of a selected
microorganism that can be classified as an alkalophilic species of Bacallus.
This type of enzyme has a very broad substrate specificity and is capable of
hydrolyzing most peptide bonds within a protein molecule.
The first concentrate consists of 1.75 °& to 7.5 °~ by
weight of the
concentrate of an hydroxide-based alkaline composition. Preferred
hydroxides for the alkaline composition are potassium and/or sodium
hydroxide. The alkaline composition preferably includes just the hydroxide,
3 o but in some use situations, may include other alkalinity enhancers.
Although
CA 02231460 2004-07-06
WO 97/05227 PCTIUS~C/l2'~52
9
in keeping with a preferred aspect of the invention, additives and enhancers
can be avoided.
The water conditioner is from 1 to 16% by weight of the
concentrate. The water conditioner is selected from the group of
polyphosphates and polyacrylic acids. The polyacrylic acids act as anti-
redeposition agents. and have a molecular weight ranging from 3000 to 6000
where the preferred polyacrylate is a homopolymer sold under the trademark
ACUSOL 445 by Rohm and Haas Company. Other polyacrylates include
copolymers of acrylic acid, malefic acid and other olefins and terpolymers
1o which are a mixture of monomers. The polyacrylate is normally available in
a solution, where the solution is 48 °b polyacrylic acid and the
balance water.
Other forms of water conditioners include various polyphosphates, such as
sodium iripolyphosphate and potassium tripolyphosphate.
It has been found that, when the diluted second concentrate is mixed
with the diluted first concentrate, enzyme activity is not affected where a
sufficient amount of hydroxide is used, such that the pH of the use solution
is in the desired range of about 9 to about 10. Because antioxidants and the
like are not used in the composition, pH stabilizing materials, such as
sodium carbonate and sodium bicarbonates, are not required. This lack of
2 o buffers is, of course, to be distinguished from the use of carbonates as a
source of alkalinity where the amounts of carbonates and bicarbonates
greatly exceed the amount which would be used when they could only act as
a buffer in addition to an alternative source of alkalinity. Furthermore, in
the use of the two-part composition as a clean-in-place system, other water
2 5 hardness control agents are optional.
The order of addition of the concentrates to water for end use is, as
would be expected, conducted in a manner to protect the activity of the
enzyme. Since the first concentrate has a high pH, it would, as one skilled
in the art appreciates, be detrimental to the enzyme activity to combine it
3 o directly with the first concentrate before dilution. The high pH in the
first
CA 02231460 2004-07-06
PCT%f : X9611 ~ 0~2
wo 97ioszz7
concentrate would greatly reduce the activity of the enzyme. Alternatively if
the 'second concentrate were first diluted and then the first concentrate
added
to the diluted second concentrate, there is also the possibility of reducing
enzyme activity, because the introduced first concentrate of high pH may in
s localized regions of the diluted second concentrate attack the enzyme and
reduce its activity. The preferred order of diluting the concentrates is as
follows. The first concentrate is diluted to the desired use solution range.
Then the second concentrate is added to the diluted first concentrate to
minimize any possibility of affecting enzyme activity. The rate of .addition
10 of the second concentrate to the diluted first concentrate can vary
depending
upon the manner in which the use solution is ~ formulated; that is either by
injection or mixing in a stir tank_
Preferred amounts in the first concentrate of the alkaline
_.._~erial is 2.So and of the polyacrylic acid of 4%. In the
second concentrate, the preferred amounts of the enzyme
stabilizing blend and enzyme are 40% by weight and 0.8% by
v;eight to provide the desired activity level.
i'he use solution provided by diluting the first and, second
concentrates with water provides from about 0.02 to 1 °b by weight of
the
2 o total weight of the use solution of the first concentrate, and about
0.0002 to
O.OS ~ by weight (2 ppm to S04 ppm) of the second concentrate. The
preferred weight range for the first concentrate in the use solution is about
0.04 to 0.6 % by weight of solution and about O.OOS °.b to 0.11 ~ by
weight
(SO ppm to 1100 ppm) of the second concentrate. The use solution is
2 5 circulated through the equipment in the normal clean-in-place process. The
preferred temperature for the use solution to effect optimum enzyme activity
is in the range of SO°C to 60°C where the pH is preferably in
the range of
8.S to 10.5. The use solution is considerably less alkaline than the previous
use solutions, particularly the highly alkaline cleaning solutions. The use
CA 02231460 1998-O1-OS
WO 97/05227 PCT/US96/12052
11
solution of this invention, with the minimum number of components, still
achieves the desired cleaning times within the range of 10 to 30 minutes.
Although it has been previously thought that enzymes for use in broad
range proteolytic activities were not stable in aqueous compositions, which
contained more than 30~ by weight of water, it has been found that with
the composition of this invention, the second concentrate provides a stable
enzyme composition under normal storage conditions. The amount of water
in the second concentrate may be well in excess of 30°b and may be as
high
as approximately 65 °~ by weight of water. Such high water levels in
the
o second concentrate permits the use of off the-shelf supplies for both the
blend of anionic detergent and liquid forms of the enzyme. The enzyme
composition, as commercially obtained from Novo for example, may have
considerable quantities of water. A further improvement in this composition
is in respect of providing a more dilute second concentrate to facilitate more
~5 accurate dispensing of the enzyme into the use solution. With certain types
of metering devices, it is more accurate to dose into the use solution larger
volumes of the first and second concentrate, particularly the second
concentrate containing the enzyme in view of the need to control and provide
the correct amount of enzyme in the use solution. The enzyme is stabilized
2 o by the blend of the alkali salt of a fatty acid and the linear
polyoxyalkylene
alcohols. With the enzyme stabilized, the amount of water in the
concentrate could be increased to further dilute the concentration of the
enzyme in the second concentrate. However, such extreme dilutions with
water and a neutral pH containing composition can lead to phase stability
2s problems. Applicant has now found that further dilution with water can be
avoided by using suitable non-aqueous fillers which are compatible with the
enzyme, maintains phase stability and optionally provides anti-freeze
properties. Such suitable non-aqueous fillers are polyols, preferably with 2
to 6 carbon atoms. Examples include propylene glycol, 1,2-propane-diol,
s o butylene glycol, ethylene glycol, hexeleneglycol, erythritol, fructose,
CA 02231460 1998-O1-OS
WO 97/05227 PCT/LJS96/12052
12
glucose, glycerol, lactose, mannitol and sorbitol. The use of the non-
aqueous filler maintains an acceptable ratio of enzyme to water while at the
same time providing a more dilute concentration of the enzyme in the second
concentrate to facilitate more accurate dosing by dispensing at each
opportunity a greater volume of the second concentrate. By using the non-
aqueous filler, not only is the ratio of enzyme to stabilizing blend and ratio
of enzyme to water kept in line, but as well the ratio of the stabilizing
blend
to water is also kept in range to ensure shelf life of the more dilute enzyme
in the concentrate and reduce the risks of freezing and phase instability.
1o The cleaner, according to this invention, has many significant
business advantages. From a production standpoint, a very trim formulation
in the sense of very few ingredients is provided so that manufacture of the
cleaner is greatly facilitated. There is no requirement to add various
additives to maintain enzyme stability, other than the unique formulation
provided in the form of a single blend which is combined with the enzyme.
Production is greatly facilitated in that water is now accommodated in the
formulation. From the standpoint of commercial use of the cleaner, the
system, when cleaning, functions at a considerably reduced pH compared to
the well known chlorinated alkaline cleaners. Hence less treatment is
2o required to discharge the cleaning effluent. It has also been found that
the
cleaner, in accordance with this invention, may be used to clean a variety of
other pieces of food handling equipment which contain a variety of other
forms of proteinaceous soils; for example, juice dispensing systems, ice
cream manufacturing equipment, fast food preparation equipment, brewery
fermentation and liquid handling equipment, and even equipment which
handles high fat, low protein food materials such as cream handling
equipment. It is quite surprising that the formulation of this invention is
successful in cleaning tank, processing equipment and the like which handles
cream. Cream is very high in fat, usually 40°~ or more but has a very
low
3 o protein content. Normally to clean cream from surfaces of processing
CA 02231460 2003-02-26
a
YCT/US96/12U~2
13
equipment, a chlorinated alkali material or solvent is required. As already
noted, these cleaners require considerable processing and treatment before
release to the environment. Surprisingly, the cleaner of this formulation
which is low in pH and does not include a solvent works quite effectively in
removing cream residues from surfaces of the handling equipment. Hence
the cleaning formulation of this invention is commercially quite usable in
that a single cleaner can be used for a variety of cleaning tasks in a food
processing facility. This greatly reduces costs in overall cleaning
management of the food processing equipment as well as providing much
io greater safety in the handling of the cleaning composition, certainly
compared to the far more hazardous cleaners, such as chlorinated alkali.
Exemplary compositions for the first and second concentrates are
provided in the following Tables 1 and 2. The various concentrates as
diluted were used in accordance with the following tests to give the results
~ 5 provided in Table 3 .
TABLE 1
~omnonent 1 of Deteryaent System
Material . A B C D E
2o Water 87.7 86.5 85.5 85.7 84.0
Sodium Hydroxide, 506 4.3 0.0 0.0 4.3 8.0
solution
Potassium Hydroxide, 45 0.0 5.5 5.5 0.0 0.0
6
solution
Acusol~ 445A 8.0 8.0 8.0 8.0 8.0
Alkali surfactantB 0.0 0.0 ~ 1.0 1.0 1.0
~ ~ ~
A - polyacryiic acid with an active molecular weight of 4500, 48 ~ solution
sold by Rohm and Haas Co.
B - Isodecyoxypropylaminodipropionic acid amphoteric surfactant sold under
the name Alkali Surfactant by Tomah Products, Inc.
CA 02231460 2003-10-07
WO 97/05227 P:T/I;SSb/1.~O5Z
14
Typical use concentration of above is 0.4 - 0.8 ~ vw.
TABLE Z
Component 2 of Detergent System
Material A B
Water 0.0 10.0 0.0
Anionic surfactant 80.0 80.0 0.0
1o Serine endoproteasec 20.0 10.0 100.0
c - Sold as ESPERASETM 8.OL by Novo Industries
0.1524 m - Comparative example
Typical use concentration of Component 2 is 0.005 to
0.02 % v/v
A series of tests were performed in which cleaning solutions were
prepared by diluting one example of Component 1 from Table 1 in water
2 o and adding an example of Component 2 from table 2. Stainless steel panels
(3" x 6" in size) of type 316 (2B finish) were thoroughly pre-cleaned in a hot
chlorinated alkaline solution and then handwashed with a sponge and hand
dishwashing detergent. When rinsed with water, clean panels exhibit
complete water sheeting, or what is often called a water break free surface.
2 5 Panels that are not completely clean are recognized by breaks in the
sheeting
action. For the purposes of this evaluation, the panels were evaluated after
each of ten cleaning cycles for a water break free surface.
The panels were suspended from a rod and hook assembly and were
soiled by completely immersing them in homogenized, pasteurized whole
3o milk held at 8° to 12°C for 10 minutes. They were then
removed from the
milk, rinsed and immediately suspended for a period of 10 minutes in test
solution held at 60°C. After cleaning, they were thoroughly rinsed with
cold tap water, followed by a deionized water rinse. The sheeting action of
the water was noted at this point. This procxdure was repeated 9 more
CA 02231460 2003-02-26
W'<) 9 i/D;'_'_7 !'CT/US9G/120s'_
times, for a total of 10 cleaning cycles. A final evaluation was done by
soaking the panels in a solution of dye that stains organic soils red. Panels
that exhibited complete water sheeting after every cycle and did riot retain
any red dye were deemed efficacious. A chlorinated alkaline cleaner
s "INTERESTS", available from Diversey Inc., was used as the positive control.
Table 3 shows some test results, indicating the combination of
components used; test temperature, water hardness level and result.
TABLE 3
Sam~,le Clear~in~ Test Results
9'o v/v 96 v/v C water Effective
Component 1 Component 2 hardness
(as pPm
CaCOs)
0. 8 96 of B 0.0196 of A 6U 500 Yes
15 0.496 of C 0.0196 of A 60 100 Yes
0.496 of D 0.0196 of A 60 300 Yes
0.49'0 of A 0.0196 of A 65 i00 Yes
0.496 of B 0.0196 of B 60 100 Yes
0.496 of E 0.0196 of A 60 100 Yes
2 0.4 96 of A 0.002 96 of 60 100 No
0 C
(The last example shows that enzyme alone is not an effective cleaner, and
that the stabilizing blend is a necessary part of the formulation for
Component 2).
2 5 To illustrate sufficient product stability of Component 2 (which does
not contain any traditional enzyme stabilizers), the following test example is
offered
CA 02231460 1998-O1-OS
WO 97/05227 PC"T/iJS96/12052
- 16
TABLE 4
C water Ei~ective
Component 1 Component hardness
2 (as
ppm CaC03)
0.490 of A 0.0196 of 60 100 Y~ '
A
where the product concentrate A (component 2) was stored for at least
3 months at 25°C without protection from light.
A representative composition for the second concentrate is set out in
the following Table 5.
TABLE 5
MATERIAL
Water 37.5
Propylene glycol 37.5
Esperase 8.OL 5.0
Anionic blend 20.0(d)
(d) - 501 by weight in water
2 o In view of the anionic blend being in an aqueous solution, the actual
amount of water in the composition is 47.5°.~by weight and the active
amount in the anionic blend is 10 3~ by weight.
The two-part enzyme-based cleaning system comprising the first and
second liquid concentrates may have a range in respect of percent by weight
of the active components of each concentrate. Such ranges are exemplified
by the above examples. The preferred percent by weight of the source of
alkalinity is about 2 to 4 °~ . The preferred percent by weight of the
water
conditioner is about 4 to 6 3b . In the second concentrate, the preferred
weight of the enzyme stabilizing blend for the more concentrated solution is
3 0 35 to 45 Q6 by weight, whereas when it is desired to have a more diluted
CA 02231460 2004-07-06
WO 97/05227 PCT/U~'95.'12C52
17
concentration of the enzyme, the blend may be in the range of 10 to 20~ by
weight. The percent by weight of the non-aqueous liquid filler, when more
dilute concentrations of the enzyme are desired is normally in the range of
25 to 55% by weight, preferably 30 to 40% by weight.
Although preferred embodiments of the invention are described herein
in detail, it will be understood by those skilled in the art that variations
may
be made thereto without departing from the spirit of the invention or the
scope of the appended claims.
