Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Enzyme component of specific activity or source
Reexamination Certificate
1999-03-23
2002-04-23
Boyer, Charles (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Enzyme component of specific activity or source
C510S161000, C510S188000, C510S194000, C510S195000, C510S220000, C510S226000, C510S235000, C510S320000, C510S321000, C510S530000
Reexamination Certificate
active
06376449
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a cleaning composition comprising an acidic substantially pepstatin-insensitive protease and a nonionic surfactant. The composition is suitable for cleaning hard surfaces or cellulosic and/or woolen fabrics at acidic pH.
BACKGROUND OF THE INVENTION
The majority of cleaning compositions used in household and industry today is alkaline.
Industrial cleaning like CIP (“Cleaning in Place”) cleaning, e.g. cleaning of membranes in dairies or other food processing industries, often involves both an acid treatment whereby mineral deposits, e.g. hardness salts (scale) such as milk-stone, are removed, and an alkaline detergent treatment removing organic matter, e.g. fats, proteins and/or sugars. The process often comprises the following steps:
RINSING→ALKALI→RINSING→ACID→RINSING
Lack of industrially producible acidic proteases effective at acidic pH has obstructed the development of enzymatic cleaning processes for dishes, laundry and industrial and household hard surfaces under acidic conditions, and only few attempts have been made to develop an exclusively acidic cleaning process although there is a desire for such advantageous acidic cleaning compositions.
DE 3833047 A1 discloses acidic ADW (Automatic Dish Washing) detergent compositions comprising a hydrolase enzyme, wherein the hydrolase may be an amylase, a protease or a lipase.
U.S. Pat. No. 5,698,507 discloses a gelled dishwashing composition having a pH of 3-5 consisting essentially of specified amounts of nonionic surfactant, citric acid, H
2
O
2
, at least one acid resistant protease enzyme, at least one amylase enzyme, hydrotrope, CaCl
2
, sodium formate, a gelling system and water. Specifically named enzymes were
Bacillus amyloliquefaciens
&agr;-amylases (e.g. Tenase 1200, Tenase L-1200 and Tenase L-340) and
Aspergillus niger
or
Aspergillus oryzae
proteases.
WO 95/02044 discloses acidic aspartic proteases obtainable from
A. aculeatus
(denoted protease I and protease II) for use in the production of food, animal feed, beverages, leather and for contact lens cleaning.
WO 96/29978 discloses an acidic oral care composition comprising acidic protease, which in the normal, slightly alkaline oral environment is substantially inactive.
WO 96/23579 discloses cleaning of membranes in a beer filtration process comprising at least a) treatment of the membrane with an enzyme-containing aqueous solution with beta-glucanase, xylanase and cellulase; b) cleaning with an acidic cleaning agent and c) cleaning with a peroxide containing alkaline solution.
SUMMARY OF THE INVENTION
We have found that proteases which retain proteolytic activity in the presence of an inhibitor selected from the group consisting of pepstatin, PEFABLOC, PMSF, or EDTA) exhibit a surprisingly good cleaning and/or activity performance at acidic conditions compared to other acidic proteases with a similar pH-activity profile. Accordingly, the invention provides advantages over the art of alkaline detergent compositions such as:
a) a peroxygen/activator bleach system, e.g. sodium-perborate or percarbonate and TAED activators that can oxidize or bleach poly-aromatic compounds present in soiling or stains becomes more effective even at low temperatures,
b) an enzyme-enhancer bleaching system, e.g. peroxidase-PPT or laccase-PPT may be used even at low temperatures.
The acidic condition has in itself a bleaching effect on some types of stains, e.g. coffee and tea,
c) an alkaline cleaning step and a rinsing step in industrial hard surface cleaning, e.g. CIP may be omitted as the acidic detergent composition may remove organic soils as well inorganic soil or stains,
d) omission of an alkaline cleaning step will reduce damaging of the hard surface.
e) Builder systems usually present in alkaline laundry detergents may in acidic laundry detergents be lowered or even omitted as surfactants usually are not precipitated by water hardness ions at acidic pH. This in turn means that scaling in cleaning equipment, e.g. a automatic laundry washing machine, may be avoided.
The invention thus provides in a first aspect an acidic detergent composition comprising an acidic protease which retains proteolytic activity in the presence of an inhibitor selected from the group consisting of pepstatin, PEFABLOC, PMSF, or EDTA and at least one nonionic surfactant, for hard surface and laundry cleaning.
DETAILED DESCRIPTION OF THE INVENTION
Definitions
The term “hard surface” as used herein relates to any surface which is essentially non-permeable to water. Examples of hard surfaces are surfaces made from metal, e.g. stainless steel or other alloys, plastics/synthetic polymers, rubber, glass, wood, concrete, rock, marble, gypsum and ceramic materials all which optionally may be coated, e.g. with paint, enamel, polymers and the like.
The term “inhibitor” as used herein relates to compounds which competitively or non-competitively interacts with the protease thereby reducing and/or destroying the enzyme activity towards the substrate of the enzyme.
The term “retains proteolytic activity” is to be construed as the protease having the property of retaining at least 75% of its activity (residual activity) measured in HPU units at pH 5.5 after treatment of the protease with inhibitor, the inhibitor being either 1 mM pepstatin, 0.1% PFABLOC, 0.1% PMSF or 100 mM EDTA.
The Protease
The protease in the context of the invention is an acidic protease which retains proteolytic activity in the presence of an inhibitor selected from the group consisting of pepstatin, PEFABLOC, PMSF, or EDTA. Inhibition by pepstatin which has the formula:
is described by Muroa S. and Oda K. (1985).
A characterization of the protease with regard to inhibition in the context of the invention is shown in WO 95/02044. An inhibition test shows that Protease I is not inhibited by pepstatin. Protease II is inhibited by pepstatin. According to Oda K. and Murao S. (1991) acidic proteases are described in two classes as carboxyl or aspartic proteases sensitive to pepstatin and pepstatin-insensitive carboxyl proteinases. Reference is also given to Muroa S. and Oda K. (1985), where this new subclass for acidic proteases was introduced.
PMSF is an inhibitor of the formula:
while PEFABLOC is a protease inhibitor of the formula:
Preferred proteases are obtainable from a microorganism, e.g. a bacterial strain, e.g. Bacillus, Pseudomonas or Xanthomonas or a fungal strain (including yeasts) such as species of the genus Aspergillus (e.g.
A. aculeatus
or
A. niger
) or Scytalidium (e.g.
S. lignicolum
).
The proteases may in a further embodiment be obtainable from a bacterium or fungus, which has been genetically modified by transforming said bacterium or fungus with a DNA vector/construct comprising DNA encoding said protease.
The protease of the invention may, in a particularly preferred embodiment, comprise one or more aspartic and/or carboxylic residues as functional groups in the active center.
Further, the protease retains proteolytic activity in the presence of inhibitors present in meat, egg white, whole blood, blood plasma, milk, beer, potatoes or beans. Such inhibitors may be ovomacroglobulin, ovomucoid or ovoglycoprotein. It is presently contemplated that inhibitors (such as competitive or non-competitive inhibitors—terms that are known to the skilled person) present in soiling which is desired to be cleaned play an important role in the cleaning process as they may inactivate or reduce activity of enzymes which would otherwise hydrolyze the soiling. This may be the reason why it has been difficult to find suitable proteases for use in acidic cleaning compositions. The protease may further have a preferred pH optimum between 2-7, more preferred between 3-6 or even more preferred between 4.5-5.5. Also the protease according to the invention may have a temperature optimum between 20-70° C., such as between 20-60° C., e.g. 30-50° C.
In a further particular embodiment the protease is Protease I or Protease II obtainable from
A. aculeatus
as described in W
Boyer Charles
Lambiris Elias J.
Novozymes A/S
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