U.S. patent application number 09/215086 was filed with the patent office on 2002-01-03 for fluidized bed matrix granule.
Invention is credited to BECKER, NATHANIEL T., CHRISTENSEN, ROBERT I. JR., GROS, ERNST H..
Application Number | 20020001835 09/215086 |
Document ID | / |
Family ID | 25541783 |
Filed Date | 2002-01-03 |
United States Patent
Application |
20020001835 |
Kind Code |
A1 |
BECKER, NATHANIEL T. ; et
al. |
January 3, 2002 |
FLUIDIZED BED MATRIX GRANULE
Abstract
Granules that include a protein core are described. The protein
core includes a protein matrix which includes a protein mixed
together with a salt. The protein matrix is layered over a seed
particle. The protein can be an enzyme or a therapeutic protein
such as a hormone. Methods of making the granules are also
described.
Inventors: |
BECKER, NATHANIEL T.;
(BURLINGAME, CA) ; CHRISTENSEN, ROBERT I. JR.;
(PINOLE, CA) ; GROS, ERNST H.; (KANTVIK,
FI) |
Correspondence
Address: |
KIRSTEN A ANDERSON
GENENCOR INTERNATIONAL INC
925 PAGE MILL ROAD
PALO ALTO
CA
943041013
|
Family ID: |
25541783 |
Appl. No.: |
09/215086 |
Filed: |
December 18, 1998 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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09215086 |
Dec 18, 1998 |
|
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08995430 |
Dec 20, 1997 |
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Current U.S.
Class: |
435/187 |
Current CPC
Class: |
C12N 9/98 20130101; C12N
9/99 20130101; Y10S 530/813 20130101; Y10S 530/811 20130101; Y10S
530/815 20130101; Y10S 530/81 20130101; C11D 3/38672 20130101 |
Class at
Publication: |
435/187 |
International
Class: |
C12N 009/98 |
Claims
What is claimed:
1. A granule comprising a protein core comprising a protein matrix
layered over a seed particle, wherein the protein matrix comprises
a protein mixed together with a salt.
2. The granule of claim 1, wherein the salt is selected from the
group consisting of an inorganic salt and an organic salt.
3. The granule of claim 1 further comprising a binder.
4. The granule of claim 3, wherein the binder is selected from the
group consisting of starch, modified starch, carrageenan, gum
arabic, guar gum, polyethylene oxide, polyvinyl pyrrolidone, and
polyethylene glycol.
5. The granule of claim 1 further comprising a barrier
material.
6. The granule of claim 1 further comprising a coating layer.
7. The granule of claim 6, wherein the coating layer is over the
seed particle.
8. The granule of claim 6, wherein the coating layer is over the
protein matrix.
9. The granule of claim 6, wherein the coating is selected from the
group consisting of polyvinyl alcohol, polyvinyl pyrrolidone,
cellulose derivatives such as methylcellulose, hydroxypropyl
methylcellulose, hydroxycellulose, ethylcellulose, carboxymethyl
cellulose, hydroxypropyl cellulose, polyethylene glycol,
polyethylene oxide, chitosan, gum arabic, xanthan and
carrageenan.
10. A granule comprising an enzyme core comprising an enzyme matrix
layered over a seed particle, wherein the enzyme matrix comprises
an enzyme mixed together with a salt.
11. The granule of claim 10, wherein the salt is selected from the
group consisting of an inorganic salt and an organic salt.
12. The granule of claim 10 further comprising a binder.
13. The granule of claim 12, wherein the binder is selected from
the group consisting of starch, modified starch, carrageenan, gum
arabic, guar gum, polyethylene oxide, polyvinyl pyrrolidone, and
polyethylene glycol.
14. The granule of claim 10 further comprising a barrier
material.
15. The granule of claim 10 further comprising a coating layer.
16. The granule of claim 15, wherein the coating layer is over the
seed particle.
17. The granule of claim 15, wherein the coating layer is over the
protein matrix.
18. The granule of claim 15, wherein the coating is selected from
the group consisting of polyvinyl alcohol, polyvinyl pyrrolidone,
cellulose derivatives such as methylcellulose, hydroxypropyl
methylcellulose, hydroxycellulose, ethylcellulose, polyethylene
glycol, polyethylene oxide, chitosan, gum arabic, xanthan and
carrageenan.
19. A method of making a granule comprising: a. fluidizing seed
particles in a fluid-bed coater; b. providing a protein matrix
formula comprising a protein mixed together with a salt; and c.
spraying the protein matrix formula on the seed particles.
20. The method of claim 19, wherein the salt is selected from the
group consisting of an inorganic salt and an organic salt.
21. The method of claim 19 further comprising applying a
binder.
22. The method of claim 21, wherein the binder is selected from the
group consisting of starch, modified starch, carrageenan, gum
arabic, guar gum, polyethylene oxide, polyvinyl pyrrolidone, and
polyethylene glycol.
23. The method of claim 1 further comprising applying a barrier
material.
24. The method of claim 19 further comprising applying a coating
layer.
25. The method of claim 24, wherein the coating layer is applied
over the seed particle.
26. The method of claim 24, wherein the coating layer is applied
over the protein matrix.
27. The method of claim 24, wherein the coating is selected from
the group consisting of polyvinyl alcohol, polyvinyl pyrollidone,
cellulose derivatives such as methylcellulose, hydroxypropyl
methylcellulose, hydroxycellulose, ethylcellulose, polyethylene
glycol, polyethylene oxide, chitosan, gum arabic, xanthan and
carrageenan.
Description
RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 08/995,430 filed Dec. 20, 1997, all of which
is hereby incorporated herein in its entirety.
BACKGROUND OF THE INVENTION
[0002] Proteins such as pharmaceutically important proteins like
hormones and industrially important proteins like enzymes are
becoming more widely used. Enzymes, for example, are used in
several industries including, for example, the starch industry, the
dairy industry, and the detergent industry. It is well known in the
detergent industry that the use of enzymes, particularly
proteolytic enzymes, has created industrial hygiene concerns for
detergent factory workers, particularly due to the health risks
associated with dustiness of the available enzymes.
[0003] Since the introduction of enzymes into the detergent
business, many developments in the granulation and coating of
enzymes have been offered by the industry. See for example the
following patents relating to enzyme granulation:
[0004] U.S. Pat. No. 4,106,991 describes an improved formulation of
enzyme granules by including within the composition undergoing
granulation, finely divided cellulose fibers in an amount of 2-40%
w/w based on the dry weight of the whole composition. In addition,
this patent describes that waxy substances can be used to coat the
particles of the granulate.
[0005] U.S. Pat. No. 4,689,297 describes enzyme containing
particles which comprise a particulate, water dispersible core
which is 150-2,000 microns in its longest dimension, a uniform
layer of enzyme around the core particle which amounts to 10%-35%
by weight of the weight of the core particle, and a layer of
macro-molecular, film-forming, water soluble or dispersible coating
agent uniformly surrounding the enzyme layer wherein the
combination of enzyme and coating agent is from 25-55% of the
weight of the core particle. The core material described in this
patent includes clay, a sugar crystal enclosed in layers of corn
starch which is coated with a layer of dextrin, agglomerated potato
starch, particulate salt, agglomerated trisodium citrate, pan
crystallized NaCl flakes, bentonite granules or prills, granules
containing bentonite, Kaolin and diatomaceous earth or sodium
citrate crystals. The film forming material may be a fatty acid
ester, an alkoxylated alcohol, a polyvinyl alcohol or an
ethoxylated alkylphenol.
[0006] U.S. Pat. No. 4,740,469 describes an enzyme granular
composition consisting essentially of from 1-35% by weight of an
enzyme and from 0.5-30% by weight of a synthetic fibrous material
having an average length of from 100-500 micron and a fineness in
the range of from 0.05-0.7 denier, with the balance being an
extender or filler. The granular composition may further comprise a
molten waxy material, such as polyethylene glycol, and optionally a
colorant such as titanium dioxide.
[0007] U.S. Pat. No. 5,254,283 describes a particulate material
which has been coated with a continuous layer of a non-water
soluble, warp size polymer. U.S. Pat. No. 5,324,649 describes
enzyme-containing granules having a core, an enzyme layer and an
outer coating layer. The enzyme layer and, optionally, the core and
outer coating layer contain a vinyl polymer.
[0008] WO 91/09941 describes an enzyme containing preparation
whereby at least 50% of the enzymatic activity is present in the
preparation as enzyme crystals. The preparation can be either a
slurry or a granulate.
[0009] WO 97/12958 discloses a microgranular enzyme composition.
The granules are made by fluid-bed agglomeration which results in
granules with numerous carrier or seed particles coated with enzyme
and bound together by a binder.
[0010] It would be desirable to produce enzyme granules with
improved stability, particularly in bleach-containing detergents at
high humidity and temperature. Current fluid-bed spray-coated
enzyme granules contain the enzyme in a relatively thin layer near
the surface of the granule. This geometry renders the enzyme more
vulnerable being chipped off of the granule in a concentrated layer
during handling and conveying operations, increasing the likelihood
and levels of airborne enzyme aerosols in the working environment.
This geometry also makes the enzyme more vulnerable to attack by
penetrating moisture and inactivating substances.
[0011] However, even in light of these developments offered by the
industry (as described above) there is a continuing need for
low-dust enzyme granules which have additional beneficial
characteristics. Additional beneficial characteristics needed in
the enzyme granulation industry are low-residue granule
formulations (where low residue is defined as a reduced tendency to
leave noticeable undissolved residues on clothes or other
material), and improved stability formulations. Accomplishing all
these desired characteristics simultaneously is a particularly
challenging task since, for example, many delayed release or
low-dust agents such as fibrous cellulose or warp size polymers
leave behind insoluble residues.
[0012] As such, there is a need for, for example, a detergent
enzyme granule which is simultaneously non-dusting, stable when
stored in detergents, and easy to manufacture in a controlled size
distribution. Granules of a controlled size distribution are
desirable in order to impart good flowability properties for
handling and blending into detergents, and to resist segregation
and settling once formulated into detergents.
[0013] Therefore, it is an object of the present invention to
provide low-dust, low residue, highly soluble enzyme granules
having increased stability. It is another object of the present
invention to provide processes which afford the formation of such
improved granules.
SUMMARY OF THE INVENTION
[0014] The present invention provides a granule that includes a
protein core that includes an protein matrix layered on a seed
particle. The protein matrix includes a protein mixed together with
a salt and optionally, a binder. Optionally, a coating can be
applied, for example, to the seed particle or over the protein
matrix.
[0015] The present invention further provides a granule that
includes an enzyme core that includes an enzyme matrix layered on a
seed particle. The enzyme matrix includes an enzyme mixed together
with a salt and optionally, a binder. Optionally, a coating can be
applied, for example, to the seed particle or over the enzyme
matrix.
[0016] The present invention also provides a method for making
granules including fluidizing seed particles in a fluidized bed
coater; providing a protein matrix formula comprising protein mixed
together with a salt; and spraying the protein matrix formula onto
the seed particles. Optionally, a coating can be applied, for
example, to the seed particle or over the enzyme matrix.
[0017] The present invention further provides a method for making
granules including fluidizing seed particles in a fluid-bed coater;
providing an enzyme matrix formula comprising enzyme mixed together
with a salt; and spraying the enzyme matrix formula onto the seed
particles. Optionally, a coating can be applied, for example, to
the seed particle or over the enzyme matrix.
DETAILED DESCRIPTION OF THE INVENTION
[0018] One embodiment of the invention is a granule that includes a
protein core that includes a protein matrix layered over a seed
particle. The protein matrix includes a protein mixed together with
a salt. Optionally, a coating can be applied, for example, to the
seed particle or over the enzyme matrix.
[0019] Another embodiment of the invention is a granule that
includes an enzyme core that includes an enzyme matrix layered over
a seed particle. The enzyme matrix includes an enzyme mixed
together with a salt. Optionally, a coating can be applied, for
example, to the seed particle or over the enzyme matrix.
[0020] A further embodiment of the invention is a method for making
granules including fluidizing seed particles in a fluid-bed coater;
providing a protein matrix formula comprising protein mixed
together with a salt; and spraying the protein matrix formula onto
the seed particles. Optionally, a coating can be applied, for
example, to the seed particle or over the enzyme matrix.
[0021] Yet another embodiment of the invention is a method for
making granules including fluidizing seed particles in a fluid-bed
coater; providing an enzyme matrix formula comprising enzyme mixed
together with a salt; and spraying the enzyme matrix formula onto
the seed particles. Optionally, a coating can be applied, for
example, to the seed particle or over the enzyme matrix.
[0022] A "protein core", an "enzyme core" or a "core" includes a
protein matrix, for example, an enzyme matrix in the case of an
enzyme core. There can be one or more layers between the seed
particle and the matrix, for example, a coating such as polyvinyl
alcohol.
[0023] Seed particles are inert particles upon which the enzyme
matrix can be layered which are composed of inorganic salts,
sugars, sugar alcohols, small organic molecules such as organic
acids or salts, minerals such as clays or silicates or a
combination of two or more of these. Suitable soluble ingredients
for incorporation into seed particles include: sodium chloride,
potassium chloride, ammonium sulfate, sodium sulfate, sodium
sesquicarbonate, urea, citric acid, citrate, sorbitol, mannitol,
oleate, sucrose, lactose and the like. Soluble ingredients can be
combined with dispersible ingredients such as talc, kaolin or
bentonite. Seed particles can be fabricated by a variety of
granulation techniques including: crystallization, precipitation,
pan-coating, fluid-bed coating, fluid bed agglomeration, rotary
atomization, extrusion, prilling, spheronization, drum granulation
and high shear agglomeration. In the granules of the present
invention, the ratio of seed particles to granules is 1:1.
[0024] The "protein matrix", "enzyme matrix" or "matrix" is an
admixture of one or more proteins such as an enzyme and a salt. The
protein and salt can be mixed, for example, in solution or as a
slurry to form the "protein matrix formula", "enzyme matrix
formula" or "matrix formula" that is applied to the seed particle.
The protein can be applied from a solution or applied in slurry
form as a suspension of crystals or precipitated protein.
[0025] By burying a protein within a matrix, the protein can be
better protected from the twin dangers of attrition and activity
loss. Also, to achieve a low dusting granular protein product, it
is necessary to control the shape and size distribution of the
granules. Uniform and reproducible size and shape also contribute
to granule stability, since particle breakup and re-agglomeration
would bring some protein near the granule surface.
[0026] Salts that can be used in the present invention include
those where the cation is sodium, potassium, magnesium, calcium,
zinc or aluminum and where the anion is chloride, bromide, iodide,
sulfate, sulfite, bisulfite, thiosulfate, phosphate, monobasic
phosphate, dibasic phosphate, hypophosphite, dihydrogen
pyrophosphate, tetraborate, borate, carbonate, bicarbonate,
metasilicate, citrate, malate, maleate, malonate, succinate,
lactate, formate, acetate, butyrate, propionate, benzoate,
tartrate, stearate, laurate, palmitate, oleate, ascorbate or
gluconate. Preferred salts include magnesium sulfate, sodium
citrate, sodium chloride, sodium sulfate, potassium sulfate,
ammonium sulfate, potassium chloride, magnesium acetate. One or
more salts can be used in the matrix. The matrix of the present
invention comprises between about 20-80% of the final granule
weight.
[0027] The granules of the present invention can also be adjusted
to a particular pH or pH range by adding the acid or base form of
the salt or salts used.
[0028] Proteins that are within the scope of the present invention
include pharmaceutically important proteins such as hormones or
other therapeutic proteins and industrially important proteins such
as enzymes.
[0029] Any enzyme or combination of enzymes may be used in the
present invention. Preferred enzymes include those enzymes capable
of hydrolyzing substrates, e.g. stains. These enzymes are known as
hydrolases which include, but are not limited to, proteases
(bacterial, fungal, acid, neutral or alkaline), amylases (alpha or
beta), lipases, cellulases and mixtures thereof. Particularly
preferred enzymes are subtilisins and cellulases, Most preferred
are subtilisins such as described in U.S. Pat. No. 4,760,025, EP
Patent 130 756 B1 and EP Patent Application WO 91/06637, which are
incorporated herein by reference, and cellulases such as Multifect
L250.TM. and Puradax.TM., commercially available from Genencor
International. Other enzymes that can be used in the present
invention include oxidases, transferases, dehydratases, reductases,
hemicellulases and isomerases.
[0030] The matrix of the granules of the present invention may
further comprise one or more binders or other excipients as known
to those skilled in the art. Suitable binders include natural
polymers such as starch, modified starch, carrageenan, gum arabic
and guar gum and synthetic polymers such as polyethylene oxide,
polyvinyl pyrrolidone, polyethylene glycol and polyethylene
oxide/polypropylene oxide.
[0031] The matrix may also further comprise plasticizers for the
binder and anti-agglomeration agents. Suitable plasticizers useful
in the present invention include polyols such as glycerol,
propylene glycol, polyethylene glycol (PEG), urea, or other known
plasticizers such as triethyl citrate, dibutyl or dimethyl
phthalate or water. Suitable anti-agglomeration agents include fine
insoluble and sparingly soluble material such as talc, TiO.sub.2,
clays, amorphous silica, magnesium stearate, stearic acid and
calcium carbonate.
[0032] The granules of the present invention can further comprise a
barrier layer. A barrier layer is used to slow or prevent the
diffusion of substances that can adversely affect the protein or
enzyme into the matrix. The barrier layer is made up of a barrier
material and can be coated over the protein core or the barrier
material can be included in the protein core. Suitable barrier
materials include, for example, inorganic salts or organic acids or
salts.
[0033] The granules of the present invention can further also
comprise one or more coating layers. For example, such coating
layers may be one or more intermediate coating layers, or such
coating layers may be one or more outside coating layers or a
combination thereof. Coating layers may serve any of a number of
functions in a granule composition, depending on the end use of the
enzyme granule. For example, coatings may render the enzyme
resistant to oxidation by bleach, bring about the desirable rates
of dissolution upon introduction of the granule into an aqueous
medium, or provide a barrier against ambient moisture in order to
enhance the storage stability of the enzyme and reduce the
possibility of microbial growth within the granule.
[0034] Suitable coatings include water soluble or water dispersible
film-forming polymers such as polyvinyl alcohol (PVA), polyvinyl
pyrrolidone (PVP), cellulose derivatives such as methylcellulose,
hydroxypropyl methylcellulose, hydroxycellulose, ethylcellulose,
carboxymethyl cellulose, hydroxypropyl cellulose, polyethylene
glycol, polyethylene oxide, gum arabic, xanthan, carrageenan,
chitosan, latex polymers, and enteric coatings. Furthermore,
coating agents may be used in conjunction with other active agents
of the same or different categories.
[0035] Suitable PVAs for incorporation in the coating layer(s) of
the granule include partially hydrolyzed, fully hydrolyzed and
intermediately hydrolyzed PVAs having low to high degrees of
viscosity. Preferably, the outer coating layer comprises partially
hydrolyzed PVA having low viscosity. Other vinyl polymers which may
be useful include polyvinyl acetate and polyvinyl pyrrolidone.
Useful copolymers include, for example, PVA-methylmethacrylate
copolymer and PVP-PVA copolymer.
[0036] The coating layers of the present invention may further
comprise one or more of the following: plasticizers, extenders,
lubricants, pigments, and optionally additional enzymes. Suitable
plasticizers useful in the coating layers of the present invention
are plasticizers including, for example, polyols such as sugars,
sugar alcohols, or polyethylene glycols (PEGs), urea, glycol,
propylene glycol or other known plasticizers such as triethyl
citrate, dibutyl or dimethyl phthalate or water. Suitable pigments
useful in the coating layers of the present invention include, but
are not limited to, finely divided whiteners such as titanium
dioxide or calcium carbonate or colored pigments and dyes or a
combination thereof. Preferably such pigments are low residue
pigments upon dissolution. Suitable extenders include sugars such
as sucrose or starch hydrolysates such as maltodextrin, corn syrup
solids, clays such as kaolin and bentonite and talc. Suitable
lubricants include nonionic surfactants such as Neodol, tallow
alcohols, fatty acids, fatty acid salts such as magnesium stearate
and fatty acid esters.
[0037] Adjunct ingredients may be added to the enzyme granules of
the present invention. Adjunct ingredients may include: metallic
salts; solubilizers; activators; antioxidants; dyes; inhibitors;
binders; fragrances; enzyme protecting agents/scavengers such as
ammonium sulfate, ammonium citrate, urea, guanidine hydrochloride,
guanidine carbonate, guanidine sulfamate, thiourea dioxide,
monoethanolamine, diethanolamine, triethanolamine, amino acids such
as glycine, sodium glutamate and the like, proteins such as bovine
serum albumin, casein and the like etc.; surfactants including
anionic surfactants, ampholytic surfactants, nonionic surfactants,
cationic surfactants and long-chain fatty acid salts; builders;
alkalis or inorganic electrolytes; bleaching agents; bluing agents
and fluorescent dyes and whiteners; and caking inhibitors.
[0038] The granules described herein may be made by methods known
to those skilled in the art of enzyme granulation specifically
fluid-bed coating.
[0039] The following examples are representative and not intended
to be limiting. One skilled in the art could choose other proteins,
enzymes, matrices, seed particles, methods and coating agents based
on the teachings herein.
EXAMPLES
Example 1
Laboratory Fluid Bed Spray Coating of Alkaline Protease/Sodium
Citrate Matrix
[0040] 607 grams of anhydrous sodium sulfate crystals sieved to
between 50 and 70 mesh were charged into a Vector FL1 fluid bed
coater and fluidized. 2812 grams of an aqueous solution containing
1406 grams of sodium citrate dihydrate was added to 1275 grams of
an aqueous protease solution with 19.1% total dry solids and 7.44%
w/w active protease. The combined solution was allowed to mix for
thirty minutes, producing a fine suspension of aggregated proteins.
The combined suspension was sprayed onto the sodium sulfate seed
particles under the following conditions:
1 Fluid feed rate 31 g/min Atomization pressure 54 psi Inlet air
temperature set point 100.degree. C. Outlet air temperature range
48 to 53.degree. C. Inlet air rate 74 cfm
[0041] A total of 2078 grams of enzyme granules were harvested as
lot A. The overall mass balance for this experiment was 89.1%.
Example 2
Laboratory Fluid Bed Spray Coating of Alkaline Protease/Magnesium
Sulfate Matrix
[0042] 607 grams of anhydrous sodium sulfate crystals sieved to
between 50 and 70 mesh were charged into a Vector FL1 fluid bed
coater and fluidized. 2812 grams of an aqueous solution containing
1406 grams of magnesium sulfate heptahydrate was added to 1271
grams of an aqueous protease solution with 19.1% total dry solids
and 7.44% w/w active protease. The combined solution was allowed to
mix for thirty minutes, producing a fine suspension of aggregated
proteins. The combined suspension was sprayed onto the sodium
sulfate seed particles under the following conditions:
2 Fluid feed rate 29 g/min Atomization pressure 54 psi Inlet air
temperature set point 100.degree. C. Outlet air temperature range
47 to 51.degree. C. Inlet air rate 75 cfm
[0043] A total of 2078 grams of enzyme granules were harvested as
lot B. The overall mass balance for this experiment was 81.7%.
Example 3
Laboratory Fluid Bed Spray Coating of Alkaline Protease/Magnesium
Sulfate Matrix
[0044] 542 grams of sucrose crystals sieved to between 35 and 50
mesh were charged into a Vector FL1 fluid bed coater and fluidized.
1709 grams of an aqueous solution containing 588 grams of magnesium
sulfate heptahydrate and 147 grams of an ethylated starch marketed
under the trade name Ethylex 2015 (A. E. Staley, Decatur, Ill.)
that had been fully hydrated by "cooking out" at 190.degree. F. for
15 minutes was added to 952 grams of an aqueous protease solution
with 19.7% total dry solids and 8.4% w/w active protease. The
combined solution was allowed to mix for thirty minutes, producing
a fine suspension of aggregated proteins. The combined suspension
was sprayed onto the sucrose seed particles under the following
conditions:
3 Fluid feed rate 29 g/min Atomization pressure 44 psi Inlet air
temperature set point 92.degree. C. Outlet air temperature range 39
to 44.degree. C. Inlet air rate 67 cfm
[0045] The coated particles were then coated with 563 grams of an
aqueous solution containing 225 grams (40% w/w) of magnesium
sulfate heptahydrate. This coating was applied under the following
conditions:
4 Fluid feed rate 30 g/min Atomization pressure 36 psi Inlet air
temperature set point 84.degree. C. Outlet air temperature range 39
to 42.degree. C. Inlet air rate 71 cfm
[0046] The magnesium sulfate coated particles were then
cosmetically coated with 2116 grams of an aqueous solution
containing 131 grams (6.2% w/w) titanium dioxide, 53 grams (2.5%
w/w) methylcellulose marketed under the trade name Methocel A-15LV
(Dow Chemical Corp.), 53 grams (2.5% w/w) of maltodextrin M150
(DE=15 from Grain Processing Corp., Muscatine, Iowa), 21 grams (1%
w/w) of a non-ionic surfactant marketed as Neodol 23/6.5 (Shell
Chemical) and 35 grams (1.67% w/w) of polyethylene glycol at a
molecular weight (MW) of 600. The cosmetic coating was applied
under the following conditions:
5 Fluid feed rate 26 g/min Atomization pressure 56 psi Inlet air
temperature set point 100.degree. C. Outlet air temperature range
46 to 54.degree. C. Inlet air rate 75 cfm
[0047] A total of 1710 grams of enzyme granules were harvested as
lot C. The overall mass balance for this experiment was 81%.
Example 4
Laboratory Fluid Bed Spray Coating of Alkaline Protease/Magnesium
Sulfate Matrix
[0048] 607 grams of anhydrous sodium sulfate crystals sieved to
between 50 and 70 mesh were charged into a Vector FL1 fluid bed
coater and fluidized. 2812 grams of an aqueous solution containing
1406 grams of zinc sulfate dihydrate was added to 1272 grams of an
aqueous enzyme solution with 19.1% total dry solids and 7.44% w/w
active protease. The combined solution was allowed to mix for
thirty minutes, allowing for complete aggregation of the proteins
in solution. The combined solution was sprayed onto the sodium
sulfate under the following conditions:
6 Fluid feed rate 29 g/min Atomization pressure 54 psi Inlet air
temperature set point 100.degree. C. Outlet air temperature range
47 to 52.degree. C. Inlet air rate 75 cfm
[0049] A total of 1840 grams of enzyme granules were harvested as
lot D. The overall mass balance for this experiment was 74.8%.
Example 5
Stability of Granules in a Detergent Matrix
[0050] The stability of many enzyme granules formulated into
bleach-containing detergents is generally excellent, showing
generally no more than about 10 to 20% loss in activity over 6
weeks storage at 30 to 37.degree. C. and 70% to 80% R.H. However,
to aid in the development and screening of granular formulations,
it is desirable to have an accelerated means of determining
relative granule stability. The conditions of the accelerated
stability test (AST) are far more severe than enzyme granules or
detergents would ever encounter in realistic storage or transport.
The AST is a "stress test" designed to discriminate differences
between formulations which would otherwise not be evident for weeks
or months.
[0051] In this test, a test detergent base was made from the
following ingredients:
7 72% WFK-1 detergent base (WFK, Forschunginstitut fuer
Reinigungstechnologie e.V., Krefeld, Germany) 25% sodium perborate
monohydrate (Degussa Corp., Allendale Park, New Jersey) 3% TAED
bleach activator (Warwick International,
(=tetraacetylethylenediamine) Mostyn, UK)
[0052] For each enzyme sample to be tested, three identical tubes
were prepared by adding 1 gram of the test base and 30 mg of enzyme
granules to a 15 ml conical tube and mixed by inverting the capped
tube 5-8 times by hand. A hole was drilled in the tube cap with a
{fraction (1/16)} inch drill bit. One of the three tubes was
assayed immediately and the other two were stored in a humidity
chamber set at 50.degree. C. and 70%R.H. One of the two stored
tubes was assayed after 1 day of storage; the second, after 3 days
of storage. Storage stability was reported for Day 1 and Day 3 by
dividing the remaining activity by the original activity at Day 0,
expressed as a percentage.
[0053] The enzyme activity was determined by adding to each tube 30
ml of 0.25M MES pH 5.5 buffer containing 20 .mu.l Catalase HP L5000
(Genencor International, Rochester, N.Y.) and incubating for 40
minutes to inactivate the perborate. After this, the enzyme was
assayed by adding 10 .mu.l of the test tube mixture and 10 .mu.l of
sAAPF protease substrate to 980 .mu.l of 0.1M Tris pH 8.6, then
incubating at 25.degree. C. over 3 minutes, and measuring the
optical absorbance at 410 nm. The slope of the absorbance vs. time
was then multiplied by the dilution factor and the known extinction
coefficient for the specific protease to obtain an enzyme activity
as concentration in mg/ml.
[0054] Samples of lots made according to Examples 1, 2 and 4 above
were subjected to the above accelerated stability test. The data is
laid out in Table 1.
8TABLE 1 Retained activity Retained activity Sample Description
after 1 day after 3 days Example 1 Sodium citrate matrix 99.7%
81.3% Example 2 Magnesium sulfate 87.6% 79.0% matrix Example 4 Zinc
sulfate matrix 65.6% 49.6%
[0055] Various other examples and modifications of the foregoing
description and examples will be apparent to a person skilled in
the art after reading the disclosure without departing from the
spirit and scope of the invention, and it is intended that all such
examples or modifications be included within the scope of the
appended claims. All publications and patents referenced herein are
hereby incorporated by reference in their entirety.
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