Thermolysin For Easy-Cleaning Of Insect Body Stains
A liquid coating material and processes of its use are provided that includes an enzyme with enzymatic activity toward a component of a biological stain and a polymeric material. Also provided are processes for facilitating the removal of a biological stain wherein an inventive liquid coating material including an enzyme is capable of enzymatically degrading of one or more components of the biological stain to facilitate biological stain removal from a substrate or coating upon which the biological stain is contacting.
This application is a continuation of U.S. application Ser. No. 15/810,700 filed Nov. 13, 2017, which is a continuation-in-part of U.S. patent application Ser. No. 14/812,087 filed on Jul. 29, 2015, which is a continuation of U.S. patent application Ser. No. 13/229,277 filed Sep. 9, 2011 (now U.S. Pat. No. 9,121,016), and U.S. application Ser. No. 15/810,700 is also a continuation-in-part of U.S. patent application Ser. No. 15/193,242 filed on Jun. 27, 2016, which is a continuation of U.S. patent application Ser. No. 13/567,341 filed Aug. 6, 2012 (now U.S. Pat. No. 9,388,370), which in turn is a continuation-in-part of U.S. patent application Ser. No. 12/820,101, filed Jun. 21, 2010 (now U.S. Pat. No. 8,796,009), the entire contents of each of which are incorporated herein by reference.
FIELDThe present invention relates generally to coating compositions including bioactive substances and methods of their use to facilitate removal of organic stains.
BACKGROUNDMany outdoor surfaces are subject to stain or insult from natural sources such as bird droppings, resins, and insect bodies. As a result, the resulting stain often leaves unpleasant marks on the surface deteriorating the appearance of the products.
Traditional self-cleaning coatings and surface are typically based on water rolling or sheeting to carry away inorganic materials. These show some level of effectiveness for removal of inorganic dirt, but are less effective for cleaning stains from biological sources, which consist of various types of organic polymers, fats, oils, and proteins each of which can deeply diffuse into the subsurface of coatings. Prior art approaches aim to reduce the deposition of stains on a surface and facilitate its removal capitalize on the “lotus-effect” where hydrophobic, oleophobic and super-amphiphobic properties are conferred to the surface by polymeric coatings containing appropriate nanocomposites. An exemplary coating contains fluorine and silicon nanocomposites with good roll off properties and very high water and oil contact angles. When used on rough surfaces like sandblasted glass, nanocoatings may act as a filler to provide stain resistance. A drawback of these “passive” technologies is that they are not optimal for use in high gloss surfaces because the lotus-effect is based on surface roughness.
Photocatalytic coatings are promising for promoting self-cleaning of organic stains. Upon the irradiation of sun light, a photocatalyst such as TiO2 chemically breaks down organic dirt that is then washed away by the water sheet formed on the super hydrophilic surface. As an example, the photocatalyst TiO2 was used to promote active fingerprint decomposition of fingerprint stains in U.S. Pat. Appl. Publ. 2009/104086. A major drawback to this technology is its limitation to use on inorganic surfaces due to the oxidative impairment of the polymer coating by TiO2. Also, this technology is less than optimal for automotive coatings due to a compatibility issue: TiO2 not only decomposes dirt, but also oxidizes polymer resins in the paint.
Therefore, there is a need for new materials or coatings that can actively promote the removal of biological stains on surfaces or in coatings and minimize the requirement for maintenance cleaning.
SUMMARYThe following summary of the invention is provided to facilitate an understanding of some of the innovative features unique to the present invention and is not intended to be a full description. A full appreciation of the various aspects of the invention can be gained by taking the entire specification, claims, drawings, and abstract as a whole.
A process of facilitating the removal of biological stains is provided including providing a liquid bioactive coating with a polymer and an enzyme such that the enzyme is capable of enzymatically degrading a component of a biological stain. An enzyme is optionally a hydrolase, optionally a protease, lipase or amylase. In some aspects, a proteins is a thermolysin-like protease is optionally a member of the M4 thermolysin-like proteases which include thermolysin or analogues thereof. Optionally, a protease is a bacterial neutral thermolysin-like-protease from Bacillus stearothermophilus or an analogue thereof.
Also provided is a composition for facilitating biological stain removal including a liquid coating material, a polymer in the liquid coating material, and an enzyme in the liquid coating material such that the enzyme is capable of degrading a biological stain component.
The following description of particular embodiment(s) is merely exemplary in nature and is in no way intended to limit the scope of the invention, its application, or uses, which may, of course, vary. The invention is described with relation to the non-limiting definitions and terminology included herein. These definitions and terminology are not designed to function as a limitation on the scope or practice of the invention but are presented for illustrative and descriptive purposes only. While processes are described as an order of individual steps or using specific materials, it is appreciated that described steps or materials may be interchangeable such that the description of the invention includes multiple parts or steps arranged in many ways as is readily appreciated by one of skill in the art.
The present disclosure is based on the catalytic activity of an enzyme to selectively degrade components of organic stains thus, promoting active stain removal. Organic stains typically include organic polymers, fats, oils, and proteins. It was traditionally difficult to identify an enzyme that was simultaneously incorporatable into or on a coating or substrate with remaining activity and successfully promote active breakdown and subsequent removal of biological stains, particularly stains from insect sources. Among other discoveries, the inventors unexpectedly discovered that a particular family of hydrolases, the bacterial thermolysins (EC 3.4.24.27), particularly the active extracellular fragment of enzyme G. stearothermophilus TLP (extracellular Sterolysin) at an activity in excess of 20,000 U/g when in a bioactive coating material successfully promoted biological stain removal whereas similar proteases, even other closely related metalloproteases, were unsuccessful.
The enzyme is either immobilized into or on coatings or substrates, or is a component of a fluid (forming a bioactive liquid coating) used to temporarily contact and coat a surface, and catalyzes the degradation of biological stain components into smaller molecules. The small product molecules are less strongly adherent to a surface or coating incorporating an enzyme, or is more easily removed with a liquid coating including an enzyme, such that gentle rinsing, optionally with water, air, or other fluid, promotes removal of the biological material from the surface or coating. Thus, the invention has utility as a composition and method for the active removal of biological stains from surfaces.
It is appreciated that the while the description herein is directed to coatings, the materials described herein may also be substrates or articles that do not require a coating thereon for promotion of functional biological stain removal. As such, the word “coating” as used herein means a material that is operable for layering on a surface of one or more substrates, or may comprise the substrate material itself. In some embodiments a coating is a temporary coating or is otherwise a material designed to be applied as a rinsing or cleaning agent such as a windshield washer fluid. As such, the methods and compositions disclosed herein are generally referred to as an enzyme associated with a coating for exemplary purposes only. One of ordinary skill in the art appreciates that the description is equally applicable to substrates themselves.
A method as provided herein includes providing a coating with an enzyme such that the enzyme is enzymatically active and capable for degrading one or more components of a biological stain that is applied prior to or after the coating is associated with a substrate. In particular embodiments a biological stain is based on bioorganic matter such as that derived from an insect, optionally an insect body.
A biological stain as defined herein is a bioorganic stain, mark, or residue left behind after an organism contacts a substrate or coating. A biological stain is not limited to marks or residue left behind after a coating is contacted by an insect body. Other sources of bioorganic stains are illustratively: insect wings, legs, or other appendages; bird droppings; fingerprints or residue left behind after a coating is contacted by an organism; or other sources of biological stains.
Enzymes are generally described according to standardized nomenclature as Enzyme Commission (EC) numbers. Examples of enzymes operable herein include: EC1, oxidoreductases; EC2, transferases; EC3, hydrolases; EC4, lyases; EC5, isomerases; or EC6, ligases. Enzymes in any of these categories can be included in a composition according to embodiments of the present disclosure.
In some embodiments, an included enzyme is a hydrolase such as a glucosidase, a protease, or a lipase. Non-limiting examples of glucosidases include amylases, chitinase, and lysozyme. Non-limiting examples of proteases include trypsin, chymotrypsin, thermolysin, subtilisin, papain, elastase, and plasminogen. Non-limiting examples of lipases include pancreatic lipase, lipoprotein lipase, and lipase PS. A lipase can include peptides having between 2 and about 1000 amino acids or having a molecular weight in the range of about 150–350,000 Daltons. Illustrative examples of proteins that function as enzymes are included in U.S. Patent Application Publication No: 2010/0210745.
Amylase is an enzyme present in some embodiments of a coating composition. Amylases have activity that break down starch. Several types of amylases are operable herein illustratively including α-amylase (EC 3.2.1.1) responsible for endohydrolysis of (1→4)-alpha-D-glucosidic linkages in oligosaccharides and polysaccharides. α-Amylase is illustratively derived from Bacillus subtilis and has the sequence found at Genbank Accession No: ACM91731 (SEQ ID NO: 1), or an analogue thereof and encoded by the nucleotide sequence of SEQ ID NO: 2. A specific example is α-Amylase from Bacillus subtilis available from Sigma-Aldrich Co., St. Louis, Mo. Additional α-Amylases include those derived from Geobacillus stearothermophilus (Accession No: AAA22227), Aspergillus oryzae (Accession No: CAA31220), Homo sapiens (Accession No: BAA14130), Bacillus amyloliquefaciens (Accession No: ADE44086), Bacillus lichemformis (Accession No: CAA01355), or other organism, or analogues thereof. It is appreciated that (β-amylases, γ-amylases, or analogues thereof from a variety of organisms are similarly operable in a bioactive coating composition.
Specific examples of amylase enzymes illustratively have 1000 U/g protease activity or more wherein one (1) U (unit) is defined as the amount of enzyme that will liberate the non-protein digestion product form potato starch of Zulkowsky (e.g. starch, treated with glycerol at 190° C.; Ber. Deutsch. Chem. Ges, 1880; 13:1395). Illustratively, the amylase has activity anywhere at or between 1,000 U/g to 500,000 U/g, or greater. It is appreciated that lower activities are operable.
A protein is optionally a lipase. A wild-type lipase is a lipase that has an amino acid sequence identical to that found in an organism in nature. An illustrative example of a wild-type lipase is that found at GenBank Accession No. ACL68189 and SEQ ID NO: 5. An exemplary nucleotide sequence encoding a wild-type lipase is found at Accession No. FJ536288 and SEQ ID NO: 6.
Lipase activity is illustratively defined in Units/gram. 1 Unit illustratively corresponds to the amount of enzyme that hydrolyzes 1 μmol acetic acid per minute at pH 7.4 and 40° C. using the substrate triacetin (Sigma-Aldrich, St. Louis, Mo., Product No. 90240). The lipase of SEQ ID NO: 5 may have an activity of 200 Units/gram.
Methods of screening for lipase activity are known and standard in the art. Illustratively, screening for lipase activity in a lipase protein or analogue thereof illustratively includes contacting a lipase or analogue thereof with a natural or synthetic substrate of a lipase and measuring the enzymatic cleavage of the substrate. Illustrative substrates for this purpose include tributyrin and triacetin both of which are cleaved by a triacylglycerol lipase to liberate butyric acid or acetic acid, respectively, that is readily measured by techniques known in the art.
A protease is optionally a bacterial metalloprotease such as a member of the M4 family of bacterial thermolysin-like proteases of which thermolysin is the prototype protease (EC 3.4.24.27) or analogues thereof. A protease is optionally the bacterial neutral thermolysin-like-protease (TLP) derived from Geobacillus stearothermophilus (Bacillus thermoproteolyticus Var. Rokko) (illustratively sold under the trade name “Thermoase C160” available from Amano Enzyme U.S.A., Co. (Elgin, Ill.)), with a sequence of residues 230-548 of SEQ ID NO: 3, or analogues thereof. A protease is optionally any protease presented in de Kreig, et al., J Biol Chem, 2000; 275(40):31115-20, or Takagi, M, et al., J Bacteriol, 1985; 163:824-831, the contents of each of which are incorporated herein by reference. Illustrative examples of a protease include the thermolysin-like-proteases from Bacillis cereus (Accession No. P05806), Lactobacillis sp. (Accession No. Q48857), Bacillis megaterium (Accession No. Q00891), Bacillis sp. (Accession No. Q59223), Alicyclobacillis acidocaldarious (Accession No. Q43880), Bacillis caldolyticus (Accession NO. P23384), Bacillis thermoproteolyticus (Accession No. P00800), Bacillus stearothermophilus (Accession No. P43133), Geobacillus stearothermophilus (P06874), Bacillus subtilis (Accession No. P06142), Bacillus amyloliquefaciens (Accession No. P06832), Lysteria monocytogenes (Accession No: P34025; P23224), or active fragments of each, among others known in the art. In particular embodiments, a TLP is the active fragment of Geobacillus stearothermophilus Stearolysin (P06874) encompassing residues 230 to 548, or an active analogue thereof. The sequences at each accession number listed herein are incorporated herein by reference.
Specific examples of proteases illustratively have 10,000 U/g protease activity or more wherein one (1) U (unit) is defined as the amount the enzyme that will liberate the non-proteinous digestion product from milk casein (final concentration 0.5%) to give Folin's color equivalent to 1 μmol of tyrosine per minute at the reaction initial reaction stage when a reaction is performed at 37° C. and pH 7.2. Illustratively, the protease activity is anywhere between 10,000 PU/g to 1,500,000 U/g or any value or range therebetween, or greater. It is appreciated that lower protease activities are operable in some embodiments. Protease activity is optionally in excess of 20,000 U/g. Optionally, protease activity is between 300,000 U/g and 2,000,000 U/g in buffer, or any value or range therebetween, or higher.
Methods of cloning, expressing, and purifying any enzyme operable herein is achievable by methods ordinarily practiced in the art illustratively by methods disclosed in Molecular Cloning: A Laboratory Manual, 2nd ed., vol. 1-3, ed. Sambrook et al., Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., 1989; Current Protocols in Molecular Biology, ed. Ausubel et al., Greene Publishing and Wiley-Interscience, New York, 1992 (with periodic updates); and Short Protocols in Molecular Biology, ed. Ausubel et al., 52 ed., Wiley-Interscience, New York, 2002, the contents of each of which are incorporated herein by reference.
An analogue of an enzyme is optionally a fragment of an enzyme or includes one or more non-wild-type amino acids in the peptide sequence. An analogue of an enzyme is a polypeptide that has some level of activity toward a natural or synthetic substrate of the enzyme. An analogue optionally has between 0.1% and 200% the activity of a wild-type enzyme. The term “enzyme” as used herein includes analogues in some embodiments. In some embodiments, the term “enzyme” is exclusive of an analogue of a wild-type enzyme.
An enzyme is a “peptide,” “polypeptide,” and “protein” (terms used herein synonymously) and is intended to mean a natural or synthetic compound containing two or more amino acids having some level of activity toward a natural or synthetic substrate of a wild-type enzyme. A wild-type enzyme is an enzyme that has an amino acid sequence identical to that found in an organism in nature. An illustrative example of a wild-type protease is that found at GenBank Accession No. P06874 and SEQ ID NO: 3.
A protein optionally functions with one or more cofactor ions or proteins. A cofactor ion is illustratively a zinc, cobalt, or calcium.
Cloning, expressing, and purifying any protein operable herein is achievable by methods ordinarily practiced in the art illustratively by methods disclosed in: Molecular Cloning: A Laboratory Manual, 2nd ed., vol. 1-3, ed. Sambrook et al., Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., 1989; Current Protocols in Molecular Biology, ed. Ausubel et al., Greene Publishing and Wiley-Interscience, New York, 1992 (with periodic updates); and Short Protocols in Molecular Biology, ed. Ausubel et al., 52 ed., Wiley-Interscience, New York, 2002.
Naturally derived amino acids present in an enzyme illustratively include the common amino acids alanine, cysteine, aspartic acid, glutamic acid, phenylalanine, glycine, histidine, isoleucine, lysine, leucine, methionine, asparagine, proline, glutamine, arginine, serine, threonine, valine, tryptophan, and tyrosine. It is appreciated that less common derivatives of amino acids that are either found in nature or chemically altered are optionally present in a protein as well such as alpha-asparagine, 2-aminobutanoic acid or 2-aminobutyric acid, 4-aminobutyric acid, 2-aminocapric acid (2-aminodecanoic acid), 6-aminocaproic acid, alpha-glutamine, 2-aminoheptanoic acid, 6-aminohexanoic acid, alpha-aminoisobutyric acid (2-aminoalanine), 3-aminoisobutyric acid, beta-alanine, allo-hydroxylysine, allo-isoleucine, 4-amino-7-methylheptanoic acid, 4-amino-5-phenylpentanoic acid, 2-aminopimelic acid, gamma-amino-beta-hydroxybenzenepentanoic acid, 2-aminosuberic acid, 2-carboxyazetidine, beta-alanine, beta-aspartic acid, biphenylalanine, 3,6-diaminohexanoic acid, butanoic acid, cyclobutyl alanine, cyclohexylalanine, cyclohexylglycine, N5-aminocarbonylornithine, cyclopentyl alanine, cyclopropyl alanine, 3-sulfoalanine, 2,4-diaminobutanoic acid, diaminopropionic acid, 2,4-diaminobutyric acid, diphenyl alanine, N,N-dimethylglycine, diaminopimelic acid, 2,3-diaminopropanoic acid, S-ethylthiocysteine, N-ethylasparagine, N-ethylglycine, 4-aza-phenylalanine, 4-fluoro-phenylalanine, gamma-glutamic acid, gamma-carboxyglutamic acid, hydroxyacetic acid, pyroglutamic acid, homoarginine, homocysteic acid, homocysteine, homohistidine, 2-hydroxyisovaleric acid, homophenylalanine, homoleucine, homoproline, homoserine, homoserine, 2-hydroxypentanoic acid, 5-hydroxylysine, 4-hydroxyproline, 2-carboxyoctahydroindole, 3-carboxylsoquinoline, isovaline, 2-hydroxypropanoic acid (lactic acid), mercaptoacetic acid, mercaptobutanoic acid, sarcosine, 4-methyl-3-hydroxyproline, mercaptopropanoic acid, norleucine, nipecotic acid, nortyrosine, norvaline, omega-amino acid, ornithine, penicillamine (3-mercaptovaline), 2-phenylglycine, 2-carboxypiperidine, sarcosine (N-methylglycine), 2-amino-3-(4-sulfophenyl)propionic acid, 1-amino-l-carboxycyclopentane, 3-thienylalanine, epsilon-N-trimethyllysine, 3-thiazolylalanine, thiazolidine 4-carboxylic acid, alpha-amino-2,4-dioxopyrimidinepropanoic acid; and 2-naphthylalanine.
An enzyme is obtained by any of various methods known in the art illustratively including isolation from a cell or organism, chemical synthesis, expression of a nucleic acid sequence, and partial hydrolysis of proteins. Chemical methods of protein synthesis are known in the art and include solid phase peptide synthesis and solution phase peptide synthesis or by the method of Hackeng, T M, et al., Proc Natl Acad Sci USA, 1997; 94(15):7845-50. An enzyme may be a naturally occurring or non-naturally occurring protein. The term “naturally occurring” refers to a protein endogenous to a cell, tissue or organism and includes allelic variations. A non-naturally occurring protein is synthetic or produced apart from its naturally associated organism or is modified and is not found in an unmodified cell, tissue or organism.
Modifications and changes can be made in the structure of an enzyme and still obtain a molecule having similar characteristics as an active enzyme (e.g., a conservative amino acid substitution). For example, certain amino acids can be substituted for other amino acids in a sequence without appreciable loss of activity or optionally to reduce or increase the activity of an unmodified protein. Because it is the interactive capacity and nature of a protein that defines the protein's functional activity, certain amino acid sequence substitutions can be made in a protein sequence and nevertheless obtain a protein with like or other desired properties. Enzymes with an amino acid sequence that is not 100% identical to that found in nature are termed analogues. An analogue optionally includes one or more amino acid substitutions, modifications, deletions, additions, or other change recognized in the art with the proviso that any such change produces an enzyme with the same type of activity (e.g. hydrolase) as the wild-type sequence. In making such changes, the hydropathic index, or the hydrophilicity of amino acids can be considered. In such changes, the substitution using amino acids whose hydropathic indices or hydrophilicity values are within ±2, those within ±1, and those within ±0.5 are optionally used.
Amino acid substitutions are optionally based on the relative similarity of the amino acid side-chain substituents, for example, their hydrophobicity, hydrophilicity, charge, size, and the like. Exemplary substitutions that take various of the foregoing characteristics into consideration are well known to those of skill in the art and include (original residue: exemplary substitution): (Ala: Gly, Ser), (Arg: Lys), (Asn: Gln, His), (Asp: Glu, Cys, Ser), (Gln: Asn), (Glu: Asp), (Gly: Ala), (His: Asn, Gln), (Ile: Leu, Val), (Leu: Ile, Val), (Lys: Arg), (Met: Leu, Tyr), (Ser: Thr), (Thr: Ser), (Tip: Tyr), (Tyr: Trp, Phe), and (Val: Ile, Leu). In particular, embodiments of the proteins can include analogues having about 50%, 60%, 70%, 80%, 90%, 95%, or 99% sequence identity to a wild-type protein.
It is further appreciated that the above characteristics are optionally taken into account when producing a protein with reduced or increased enzymatic activity. Illustratively, substitutions in a substrate binding site, exosite, cofactor binding site, catalytic site, or other site in a protein may alter the activity of the enzyme toward a substrate. In considering such substitutions the sequences of other known naturally occurring or non-naturally occurring like enzymes may be taken into account. Illustratively, a corresponding mutation to that of Asp213 in thermolysin is operable such as that done by Mild, Y, et al., Journal of Molecular Catalysis B: Enzymatic, 1996; 1:191-199. Optionally, a substitution in thermolysin of L144 such as to serine alone or along with substitutions of G8C/N60C/S65P are operable to increase the catalytic efficiency by 5-10 fold over the wild-type enzyme. Yasukawa, K, and Inouye, K, Biochimica et Biophysica Acta (BBA)-Proteins & Proteomics, 2007; 1774:1281-1288. The mutations in the bacterial neutral protease from Bacillus stearothermophilus of N116D, Q119R, D150E, and Q225R as well as other mutations similarly increase catalytic activity. De Kreig, A, et al., J. Biol. Chem., 2002; 277:15432-15438. De Kreig also teach several substitutions including multiple substitutions that either increase or decrease the catalytic activity of the protein. Id. and De Kreig, Eur J Biochem, 2001; 268(18):4985-4991. Other substitutions at these or other sites optionally similarly affect enzymatic activity. It is within the level of skill in the art and routine practice to undertake site directed mutagenesis and screen for subsequent protein activity such as by the methods of De Kreig, Eur J Biochem, 2001; 268(18):4985-4991.
An enzyme is optionally an analogue of a wild-type enzyme. An analogue of an enzyme has an amino acid sequence that when placed in similar conditions to a wild-type protein possess some level of the activity of a wild-type enzyme toward the same substrate. An analogue optionally has 500%, 250%, 200%, 150%, 110%, 99%, 98%, 97%, 96%, 95%, 94%, 93%, 92%, 91%, 90%, 85%, 80%, 75%, 70%, 60%, 50%, 25%, 10%, 5%, or any value or range of values therebetween, the activity of a wild-type protein. Any modification to a wild-type protein may be used to generate an analogue. Illustratively, amino acid substitutions, additions, deletions, cross-linking, removal or addition of disulfide bonds, or other modification to the sequence or any member of the sequence may be used to generate an analogue. An analogue is optionally a fusion protein that includes the sequences of two or more wild-type proteins, fragments thereof, or sequence analogues thereof.
Methods of screening for protein activity are known and standard in the art. Illustratively, screening for activity of an enzyme illustratively includes contacting an enzyme with a natural or synthetic substrate of an enzyme and measuring the enzymatic cleavage of the substrate. Illustrative substrates for this purpose include casein, which is cleaved by a protease to liberate folin-positive amino acids and peptides (calculated as tyrosine) that are readily measured by techniques known in the art. The synthetic substrate furylacryloylated tripeptide 3-(2-furylacryloyl)-L-glycyl-L-leucine-L-alanine obtained from Bachem AG, Bubendorf, Switzerland is similarly operable. Illustrative substrates of α-Amylase include long chain carbohydrates such as amylose or amylopectin that make up starch. Other methods of screening for α-Amylase activity include the colorimetric assay of Fischer and Stein, Biochem. Prep., 1961, 8, 27-33. It is appreciated that one of ordinary skill in the art can readily envision methods of screening for enzyme activity with the enzyme present in or on a variety of materials.
An enzyme is illustratively recombinant. Methods of cloning, synthesizing or otherwise obtaining nucleic acid sequences encoding a protein are known and standard in the art. Similarly, methods of cell transfection and protein expression are similarly known in the art and are applicable herein. Exemplary cDNA encoding the protein sequence of SEQ ID NO: 1 is the nucleotide sequence SEQ ID NO: 2. Exemplary cDNA encoding the protein sequence of SEQ ID NO: 3 is the nucleotide sequence found at accession number M11446 and SEQ ID NO: 4. Exemplary cDNA encoding the protein sequence of SEQ ID NO: 5 is the nucleotide sequence SEQ ID NO: 6.
An enzyme may be coexpressed with associated tags, modifications, other proteins such as in a fusion protein, or other modifications or combinations recognized in the art. Illustrative tags include 6×His, FLAG, biotin, ubiquitin, SUMO, or other tag known in the art. A tag is illustratively cleavable such as by linking to protein via a target sequence that is cleavable by an enzyme known in the art illustratively including Factor Xa, thrombin, SUMOstar protein as obtainable from Lifesensors, Inc., Malvern, Pa., or trypsin. It is further appreciated that chemical cleavage is similarly operable with an appropriate cleavable linker.
Protein expression is illustratively accomplished following transcription of a protein nucleic acid sequence, translation of RNA transcribed from the protein nucleic acid sequence or analogues thereof. An analog of a nucleic acid sequence is any sequence that when translated to protein will produce a wild-type protein or an analogue of a wild-type protein. Protein expression is optionally performed in a cell based system such as in E. coli, Hela cells, or Chinese hamster ovary cells. It is appreciated that cell-free expression systems are similarly operable.
It is recognized that numerous analogues of protein are operable and within the scope of the present invention including amino acid substitutions, alterations, modifications, or other amino acid changes that increase, decrease, or not do alter the function of the protein sequence. Several post-translational modifications are similarly envisioned as within the scope of the present disclosure illustratively including incorporation of a non-naturally occurring amino acid, phosphorylation, glycosylation, addition of pendent groups such as biotin, avidin, fluorophores, lumiphores, radioactive groups, antigens, or other molecules.
It is recognized that numerous analogues of an enzyme are operable and within the scope of the present disclosure including amino acid substitutions, alterations, modifications, or other amino acid changes that increase, decrease, or not alter the function of the enzyme protein sequence. Several post-translational modifications are similarly envisioned as within the scope of the present invention illustratively including incorporation of a non-naturally occurring amino acid, phosphorylation, glycosylation, addition of pendent groups such as biotinylation, fluorophores, lumiphores, radioactive groups, antigens, or other molecules.
An inventive method uses an inventive composition that is one or more enzymes incorporated into a substrate itself or into a coating, optionally for application on a substrate. The enzyme is optionally non-covalently associated and/or covalently attached to the substrate or coating material or is otherwise associated therewith such as by bonding to the surface or by intermixing with the substrate/coating material during manufacture such as to produce entrapped enzyme. In some embodiments the enzyme is covalently attached to the substrate or coating material either by direct covalent interaction between the enzyme and one or more components of the substrate or coating material or by association via a link moiety such as that described in U.S. Pat. App. Publ. No. 2008/0119381, the contents of which are incorporated herein by reference. In some embodiments, such as in coatings useful as cleaning agents, illustratively, windshield washing solutions, an enzyme is in solution or suspension within the coating solution.
There are several ways to associate an enzyme with a substrate or coating. One of which involves the application of covalent bonds. Specifically, free amine groups of the enzyme may be covalently bound to an active group of the substrate. Such active groups include alcohol, thiol, aldehyde, carboxylic acid, anhydride, epoxy, ester, or any combination thereof. This method of incorporating enzyme delivers unique advantages. First, the covalent bonds tether the enzymes permanently to the substrate and thus place them as an integral part of the final composition with much less, if any at all, leakage of the protease. Second, the covalent bonds provide extended enzyme lifetime. Over time, proteins typically lose activity because of the unfolding of their polypeptide chains. Chemical bonding such as covalent bonding effectively restricts such unfolding, and thus improves the protein life. The life of a protein is typically determined by comparing the amount of activity reduction of a protein that is free or being physically adsorbed with that of a protein covalently-immobilized over a period of time.
Enzymes are optionally uniformly dispersed throughout the substrate or coating network to create a substantially homogenous protein platform. In so doing, enzymes may be first modified with polymerizable groups. The modified enzymes may be solubilized into organic solvents, optionally, in the presence of surfactant, and thus engage the subsequent polymerization with monomers such as methyl methacrylate (MMA) or styrene in the organic solution. The resulting composition optionally includes enzyme molecules homogeneously dispersed throughout the network.
Enzymes are optionally attached to surfaces of a substrate. An attachment of proteases corresponding to approximately 100% surface coverage was achieved with polystyrene particles with diameters range from 100 to 1000 nm.
Chemical methods of protease attachment to materials will naturally vary depending on the functional groups present in the enzyme and in the material components. Many such methods exist. For example, methods of attaching proteins (such as enzymes) to other substances are described in O'Sullivan et al, Methods in Enzymology, 1981; 73:147-166 and Erlanger, Methods in Enzymology, 1980; 70:85-104, each of which are herein incorporated herein by reference.
Enzymes are optionally present in a coating that is layered upon a substrate wherein the enzyme is optionally entrapped in the coating material, admixed therewith, modified and integrated into the coating material or layered upon a coating similar to the mechanisms described for interactions between a protease and substrate material.
Materials operable for interactions with an enzyme to form an active substrate or coating illustratively include organic polymeric materials. The combination of these materials and an enzyme form a protein-polymer composite material that is used as a substrate material or a coating.
Methods of preparing protein-polymer composite materials illustratively include use of aqueous solutions of enzyme and non-aqueous organic solvent-borne polymers to produce bioactive organic solvent-borne protein-polymer composite materials.
Methods of preparing protein-polymer composite materials are illustratively characterized by dispersion of enzyme in solvent-borne resin prior to curing and in the composite materials, in contrast to forming large aggregates of the bioactive proteins which diminish the functionality of the proteases and protein-polymer composite materials. Enzymes are optionally dispersed in the protein-polymer composite material such that the enzymes are unassociated with other bioactive proteins and/or form relatively small particles of associated proteins. Illustratively, the average particle size of enzyme particles in the protein-polymer composite material is less than 10 μm (average diameter) such as in the range of 1 nm to 10 μm, inclusive.
Curable protein-polymer compositions are optionally two-component solvent-borne (2K SB) compositions. Optionally, one component systems (1K) are similarly operable. Illustratively, an enzyme is entrapped in a coating material such as a latex or enamel paint, varnish, polyurethane gels, or other coating materials. Illustrative examples of incorporating enzymes into paints are presented in U.S. Pat. No. 5,998,200, the contents of which are incorporated herein by reference.
In two-component systems the two components are optionally mixed shortly before use, for instance, application of the curable protein-polymer composition to a substrate to form an enzyme containing coating such as a bioactive clear coat. Generally described, the first component contains a crosslinkable polymer resin and the second component contains a crosslinker. Thus, the emulsion is a first component containing a crosslinkable resin and the crosslinker is a second component, mixed together to produce the curable protein-polymer composition.
A polymer resin included in methods and compositions of the present disclosure can be any film-forming polymer useful in coating or substrate compositions, illustratively clear coat compositions. Such polymers illustratively include, aminoplasts, melamine formaldehydes, carbamates, polyurethanes, polyacrylates, epoxies, polycarbonates, alkyds, vinyls, polyamides, polyolefins, phenolic resins, polyesters, polysiloxanes; and combinations of any of these or other polymers.
In particular embodiments, a polymer resin is crosslinkable. Illustratively, a crosslinkable polymer has a functional group characteristic of a crosslinkable polymer. Examples of such functional groups illustratively include acetoacetate, acid, amine, carboxyl, epoxy, hydroxyl, isocyanate, silane, vinyl, other operable functional groups, and combinations thereof.
Examples of organic crosslinkable polymer resins includes aminoplasts, melamine formaldehydes, carbamates, polyurethanes, polyacrylates, epoxies, polycarbonates, alkyds, vinyls, polyamides, polyolefins, phenolic resins, polyesters, polysiloxanes, or combinations thereof.
A cross linking agent is optionally included in the composition. The particular crosslinker selected depends on the particular polymer resin used. Non-limiting examples of crosslinkers include compounds having functional groups such as isocyanate functional groups, epoxy functional groups, aldehyde functional groups, and acid functionality.
In particular embodiments of protein-polyurethane composite materials, a polymer resin is a hydroxyl-functional acrylic polymer and the crosslinker is a polyisocyanate.
A polyisocyanate, optionally a diisocyanate, is a crosslinker reacted with the hydroxyl-functional acrylic polymer according to embodiments of the present invention. Aliphatic polyisocyanates are preferred polyisocyanates used in processes for making protein-polymer composite materials for clearcoat applications such as in automotive clearcoat applications. Non-limiting examples of aliphatic polyisocyanates include 1,4-butylene diisocyanate, 1,4-cyclohexane diisocyanate, 1,2-diisocyanatopropane, 1,3-diisocyanatopropane, ethylene diisocyanate, lysine diisocyanate, 1,4-methylene bis (cyclohexyl isocyanate), diphenylmethane 4,4′-diisocyanate, an isocyanurate of diphenylmethane 4,4′-diisocyanate, methylenebis-4,4′-isocyanatocyclohexane, 1,6-hexamethylene diisocyanate, an isocyanurate of 1,6-hexamethylene diisocyanate, isophorone diisocyanate, an isocyanurate of isophorone diisocyanate, p-phenylene diisocyanate, toluene diisocyanate, an isocyanurate of toluene diisocyanate, triphenylmethane 4,4′,4″-triisocyanate, tetramethyl xylene diisocyanate, and meta-xylene diisocyanate.
Curing modalities are those typically used for conventional curable polymer compositions.
Protease-polymer composite materials used in embodiments of the present disclosure are optionally thermoset protein-polymer composite materials. For example, a substrate or coating material is optionally cured by thermal curing. A thermal polymerization initiator is optionally included in a curable composition. Thermal polymerization initiators illustratively include free radical initiators such as organic peroxides and azo compounds. Examples of organic peroxide thermal initiators illustratively include benzoyl peroxide, dicumylperoxide, and lauryl peroxide. An exemplary azo compound thermal initiator is 2,2′-azobisisobutyronitrile.
Conventional curing temperatures and curing times can be used in processes according to embodiments of the present disclosure. For example, the curing time at specific temperatures, or under particular curing conditions, is determined by the criteria that the cross-linker functional groups are reduced to less than 5% of the total present before curing. Cross-linker functional groups can be quantitatively characterized by FT-IR or other suitable method. For example, the curing time at specific temperatures, or under particular curing conditions, for a polyurethane protein-polymer composite of the present invention can be determined by the criteria that the cross-linker functional group NCO is reduced to less than 5% of the total present before curing. The NCO group can be quantitatively characterized by FT-IR. Additional methods for assessing the extent of curing for particular resins are well-known in the art. Illustratively, curing may include evaporation of a solvent or by exposure to actinic radiation, such as ultraviolet, electron beam, microwave, visible, infrared, or gamma radiation.
One or more additives are optionally included for modifying the properties of the protease -polymer composite material and/or the admixture of organic solvent and polymer resin, the aqueous lipase solution, the emulsion, and/or the curable composition. Illustrative examples of such additives include a UV absorbing agent, a plasticizer, a wetting agent, a preservative, a surfactant, a lubricant, a pigment, a filler, and an additive to increase sag resistance.
A substrate or coating including an enzyme is illustratively an admixture of a polymer resin, a surfactant and a non-aqueous organic solvent, mixed to produce an emulsion. The term “surfactant” refers to a surface active agent that reduces the surface tension of a liquid in which it is dissolved, or that reduces interfacial tension between two liquids or between a liquid and a solid.
Surfactants used can be of any variety including amphoteric, silicone-based, fluorosurfactants, anionic, cationic and nonionic such as described in K. R. Lange, Surfactants: A Practical Handbook, Hanser Gardner Publications, 1999; and R. M. Hill, Silicone Surfactants, CRC Press, 1999, incorporated herein by reference. Examples of anionic surfactants illustratively include alkyl sulfonates, alkylaryl sulfonates, alkyl sulfates, alkyl and alkylaryl disulfonates, sulfonated fatty acids, sulfates of hydroxyalkanols, sulfosuccinic acid esters, sulfates and sulfonates of polyethoxylated alkanols and alkylphenols. Examples of cationic surfactants include quaternary surfactants and amineoxides. Examples of nonionic surfactants include alkoxylates, alkanolamides, fatty acid esters of sorbitol or manitol, and alkyl glucamides. Examples of silicone-based surfactants include siloxane polyoxyalkylene copolymers.
In some embodiments, a coating is formed of materials that produce a liquid bioactive coating material suitable for use as a cleaning fluid, illustratively a windshield washer fluid. As one example, the inventors surprisingly discovered that inclusion of the active extracellular fragment of enzyme G. stearothermophilus TLP at an activity in excess of 20,000 U/g in a coating material provides unexpectedly superior insect biological stain removal relative to other enzymes, and particularly other proteases. A coating material is optionally a cleaning fluid. Illustrative examples of a cleaning fluid include those described in: U.S. Pat. Nos. 6,881,711; and 6,635,188; the contents of which are incorporated herein by reference. Illustrative examples of fluids for use as a coating material include those sold as BUGWASH by Prestone Products, Corp., XTREME BLUE by Camco Mfg, Inc., Greenboro, NC, and RAIN X Delcer, from ITW Global Brands, Houston, Tex.
While any commercially available windshield washer fluid can be used as a cleaning fluid for addition of an enzyme, the inventors surprisingly discovered that coating materials that are low in alcohol content (e.g. less than 0.8%) and have a pH in excess of 5.0, optionally in excess of 8.0, optionally between 5.0 and 12.0, or any value or range therebetween, possess far superior protease activity stability. Optionally, a pH is between 10.0 and 11.0. The pH activity and stability data are surprising for the additional reasons that it is known in the art that the enzyme has an optimal activity at about pH 7.6 with rapidly decreasing activity at higher pH levels. For example, the activity in Britton-Robinson buffer is less than 20% peak activity at a pH at or above 10.0. Additionally, stability falls of significantly at a pH above 5. The combined high activity and stability of the active extracellular fragment of enzyme G. stearothermophilus TLP, for example, at relatively high pH values such as above 5.0, optionally above 8.0, particularly above 10.0, more particularly between 10.0 and 11.0, creates an unexpectedly cleaning coating material relative to coating materials combined with other proteases.
In some embodiments, a liquid bioactive coating material includes a surfactant, an ammonia compound, an alcohol, and water. Water is optionally a predominant. A surfactant in such embodiments is illustratively a nonionic surfactants, anionic surfactants, cationic surfactants, zwitterionic surfactants, and mixtures thereof, with specific examples of surfactants being octylphenol ethoxylates, alkyl polyglycosides, sodium alkyl sulfates, and mixtures thereof. A surfactant is optionally present in an amount at or between 0.001% to about 0.25% (by weight). An ammonia compound is illustratively ammonium carbamate, ammonium carbonate, ammonium bicarbonate, ammonium hydroxide, ammonium acetate, ammonium borate, ammonium phosphate, an alkanolamine having 1 to 6 carbon atoms, and ammonia, or combinations thereof. An ammonia compound is optionally present at or between 0.005% to about 1.0% (by weight of NH3). An alcohol is illustratively one or more: water miscible alcohols having 1 to 6 carbon atoms, water miscible glycols and glycol ethers having 2 to 15 carbon atoms and mixtures thereof. Preferred alcohols include methanol, ethanol, isopropanol, propanol, butanol, furfuryl alcohol, tetrahydrofurfuryl alcohol (“THFA”) and 1-amino-2-propanol. Preferred glycols and glycol ethers include ethylene glycol, propylene glycol, 2-butoxyethanol sold as BUTYL CELLOSOLVE®, 2-methoxyethanol, 1-methoxy-2-propanol, ethylene glycol dimethyl ether, 1,2-dimethoxypropane, 2-(2-propoxyethoxy)ethanol, 2-[2-(2-propoxyethoxy)ethoxy]ethanol, 2-(2-isopropoxyethoxy)ethanol, 2-[2-(2 isopropoxyethoxy)ethoxy]ethanol, 2-(2-butoxyethoxy)ethanol, 2-[2-(2-butoxyethoxy)ethoxy]ethanol, 2-(2-isobutoxyethoxy)ethanol, 2-[2-(2 isobutoxyethoxy)ethoxy]ethanol, 2-(2-propoxypropoxy)-propan-1-ol, 2-[2-(2-propoxypropoxy)propoxy]propan-1-ol, 2-(2-isopropoxypropoxy)-propan-1-ol, 2-[2-(2-isopropoxypropoxy)propoxy]propan-1-ol, 2-(2-butoxypropoxy)-propan-1-ol, 2-[2(2-butoxypropoxy)propoxy]propan-1-ol, 2-(2-isobutoxypropoxy)-propan-1-ol and 2[2-(2-isobutoxypropoxy)propoxy]propan-1-ol. Preferably, ethanol, isopropanol, 2-butoxyethanol or 1-amino-2-propanol methanol, ethanol, isopropanol, propanol, butanol, furfuryl alcohol, tetrahydrofurfuryl alcohol, 1-amino-2-propanol, ethylene glycol, propylene glycol, and 2-butoxyethanol, or combinations thereof are used.
A liquid bioactive coating material is optionally formed by combining a coating material with one or more proteases such that the protease is in solution or suspension. A protease containing coating material is optionally mixed such as by vortex mixing until a solution of protease is achieved. The amount of enzyme is illustratively 0.1 to 50 mg in ˜4 L coating material.
When a surface, which is optionally a substrate or a coated substrate, is contacted with biological material to produce a biological stain, the enzyme or combinations of enzymes in a coating material are placed in contact with the stain, or components thereof. The contacting allows the enzymatic activity of the enzyme to interact with and enzymatically alter the components of the stain improving its removal from the substrate or coating.
Enzyme containing substrates or coatings have a surface activity generally expressed in Units/cm2. Substrates and coatings optionally have functional surface activities of greater than 0.0075 Units/cm2. In some embodiments surface activity is between 0.0075 Units/cm2 and 0.05 Units/cm2 inclusive. Optionally, surface activity is between 0.0075 Units/cm2 and 0.1 Units/cm2 inclusive. Optionally, surface activity is between 0.01 Units/cm2 and 0.05 Units/cm2 inclusive.
It is appreciated that the inventive methods of facilitating stain removal will function at any temperature whereby the enzyme is active. Optionally, the inventive process is performed at 4° C. Optionally, an inventive process is performed at 25° C. Optionally, an inventive process is performed at ambient temperature. It is appreciated that the inventive process is optionally performed from 4° C. to 125° C., or any single temperature or range therein.
The presence of enzyme combined with the material of a substrate or a coating, optionally, with water or other fluidic rinsing agent, breaks down stains for facilitated removal.
Methods involving conventional biological techniques are described herein. Such techniques are generally known in the art and are described in detail in methodology treatises such as Molecular Cloning: A Laboratory Manual, 3rd ed., vol. 1-3, ed. Sambrook et al., Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., 2001; Current Protocols in Molecular Biology, ed. Ausubel et al., Greene Publishing and Wiley-Interscience, New York, 1992 (with periodic updates); and Short Protocols in Molecular Biology, ed. Ausubel et al., 52 ed., Wiley-Interscience, New York, 2002.
Various aspects of the present invention are illustrated by the following non-limiting examples. The examples are for illustrative purposes and are not a limitation on any practice of the present invention. It will be understood that variations and modifications can be made without departing from the spirit and scope of the invention.
EXAMPLE 1Production of a bacterial neutral protease from Bacillus stearothermophilus containing material operable for coating a substrate.
Materials: Freeze-dried crickets are purchased from PetSmart. Cricket bodies reportedly contain 58.3% protein. (D. Wang, et al., Entomologic Sinica, 2004; 11:275-283, incorporated herein by reference.) α-Amylase, Lipase PS, Protease N, Protease A, Protin SD AY-10, active extracellular fragment of G. stearothermophilus TLP (THERMOASE C160), and THERMOASE GL30 (low activity preparation of B. stearothermophilus TLP) are obtained from AMANO Enzyme Inc. (Nagoya, JAPAN). Polyacrylate resin Desmophen A870 BA, and the hexamethylene diisocyanate (HDI) based polyfunctional aliphatic polyisocyanate resin Desmodur N 3600 are obtained from Bayer Corp. (Pittsburgh, Pa.). The surfactant BYK-333 is obtained from BYK-Chemie (Wallingford, Conn.). 1-butanol and 1-butyl acetate are obtained from Sigma-Aldrich Co. (Missouri, USA). Aluminum paint testing panels are purchased from Q-Lab Co. (Cleveland, USA). All other reagents involved in the experiments are of analytical grade.
Enzyme based 2K SB PU coatings are prepared by either a draw-down method or by spray application and used for subsequent biological stain removal experiments. Each enzyme is dissolved in DI water to a final enzyme solution concentration of 200 mg/mL for all water borne (WB) coatings. For solvent borne (SB) enzyme prepared coatings 50 mg/mL enzyme is used. A solution of 150 ml of deionized water containing 1.5 g of the active extracellular fragment of enzyme G. stearothermophilus TLP is first purified by ultrafiltration (molecular weight cut-off of 30 kDa, all liquids were kept on ice).
For the draw-down method or coating preparation, the surfactant BYK 333 is diluted with 1-butanol to the concentration of 17% by weight. The resin part of the 2K SB PU coating is prepared by mixing 2.1 g of Desmophen A 870 with 0.5 mL of 1-butyl acetate and 0.1 mL surfactant in a 20 mL glass vial. The solution is mixed using a microspatula for 1 min followed by addition of 0.6 mL of enzyme solution (or DI water for control coating without enzyme) followed by mixing for another 1 min. This solution is then poured out into a 20-mL glass vial with 0.8 g of NA 3600 and stirred for 1 min. This formulation produces an enzyme concentration of 6% by weight. Pre-cleaned aluminum testing panels are coated with the enzyme containing coating material using a draw-down applicator with a wet film thickness of 2 mils. The coating panels are baked at 80° C. for 30 minutes and then cured at ambient temperature for 7 days.
For the spray application method, coating are prepared essentially as described in
A cleaning fluid as a coating material including the active extracellular fragment of enzyme G. stearothermophilus TLP is produced by intermixing the TLP at 0.1 mg to 20 mg/liter of the cleaning fluid in a mixing vessel at room temperature at least one hour prior to use. The cleaning fluid is formed from 1-amino-2-propanol (0.2% w/w), 4-(1,1,3,3-Tetramethylbutyl)phenyl-polyethylene glycol t-Octylphenoxypolyethoxyethanol Polyethylene glycol tert-octylphenyl ether (TRITON X-100) (0.04% w/w), ammonia (0.084% w/w; from 28% NH3 in water); with the balance water. All of the components of the cleaning fluid are obtained commercially as follows: TRITON X-100 from Union Carbide/Dow Chemical; ammonia and 1-amino-2propanol from Sigma-Aldrich Chemical Company Inc.; and active extracellular fragment of Geobacillus stearothermophilus TLP (THERMOASE C160) from Amano Enzyme, Inc. A cleaning fluid is mixed with the active extracellular fragment G. stearothermophilus TLP by agitation or by vortex mixing. The resulting G. stearothermophilus TLP containing cleaning fluid is stored at ambient temperature.
EXAMPLE 2Preparation of biological stains and application to a coated substrate. An exemplary schematic of an experimental procedure is provided in
Drying time affects stain removal time. Stained coated substrate panels prepared with coatings as in Example 1 and insect stains as in Example 2 are subjected to drying at 40° C. for various times. The rinsing time of stain drops strongly depends on the drying time. The control protease free coating, after being dried for 5 min, produces firmly adhered stain drops that are not removed by rinsing for 3 hr (Table 1).
For the active extracellular fragment of enzyme G. stearothermophilus TLP containing coated panes, the rinsing time increases with longer drying time yet at equivalent drying times relative to control the protease containing coating promotes dramatically improved stain removal. (Table 2).
Increased rinsing intensity reduces stain removal time. The panels prepared as in Examples 1 and 2 are subjected to various rinsing intensities. Reduced rinsing time is achieved by increasing rinsing intensity for the active extracellular fragment of enzyme G. stearothermophilus TLP containing coatings on substrates (Table 3).
Coatings containing various enzymes are prepared as in Example 1. Each coating is analyzed for performance by measurement of average rinsing time using a standard protocol of applying a cricket stain to a coated substrate, drying for 5 min at 40° C. and rinsing in water or in protease containing cleaning fluid at an intensity of 300 RPM. For removal of insect stains by a TLP containing cleaning fluid, the fluid is prepared as described in Example 1. Insect material is applied onto a glass substrate dried on a heating plate at 60° C. for a period. After drying, drops of 50 μ1 enzyme containing cleaning fluids of Example 1 are added onto dry stain spots via a multi-channel pipette, followed by an incubation for 10 minutes at ambient temperature. The identical volume of control (protease free) washer fluids are added onto the control spots on the same substrate. The substrate is then immersed face-up into a deionized water bath while horizontally shaking at 100 rpm. The stain spots retained on the coatings after a desired shaking time are counted during the washing for quantitative analysis. The control and various protease containing coatings are also evaluated for roughness, contact angle, and gloss. The results are depicted in Table 4.
The active extracellular fragment of enzyme G. stearothermophilus TLP based coatings as well as other TLP containing cleaning fluids have an improved self-cleaning function against insect body stains compared with other coating materials containing either no enzyme or alternative enzymes (no enzyme, Lipase PS, and α-Amylase). In addition, the coating surface properties are insignificant different between the active extracellular fragment of enzyme G. stearothermophilus TLP based coating and the control, Lipase PS, or α-Amylase based coatings. These results indicate that physical characteristics of the coatings are not differentially affecting the coating performance.
The rinsing times of each enzyme containing coating is compared.
Similar results are observed comparing an active extracellular fragment of enzyme G. stearothermophilus TLP based coating with a lipase and α-Amylase based coating. In
Similarly excellent results are observed for cleaning fluids containing active extracellular fragment of enzyme G. stearothermophilus TLP.
Affect of surface heating on protease function. Panels coated with the active extracellular fragment of enzyme G. stearothermophilus TLP based coatings as in Example 1 are subjected to baking temperatures of 100° C. for 10 days followed by determination of change in surface enzyme activity. Proteolytic surface activity of protease containing coatings is determined following the method of Folin and Ciocalteau, J. Biol. Chem., 1927; 73: 627-50, incorporated herein by reference. Briefly, 1 mL of 2% (w/v) casein in sodium phosphate (0.05 M; pH 7.5) buffer solution is used as substrate together with 200 μl of sodium acetate, 5 mM calcium acetate (10 mM; pH 7.5). The substrate solution is pre-incubated in a water bath for 3 min to reach 37° C. The reaction is started by adding one piece of sample plate coated with the active extracellular fragment of enzyme G. stearothermophilus TLP based coating (1.2×1.9 cm2) followed by shaking for 10 min at 200 rpm at which time the reaction is stopped by adding 1 ml of 110 mM tricholoroacetic acid (TCA) solution. The mixture is incubated for 30 min at 37° C. prior to centrifugation. The equivalent of tyrosine in 400 μL of the TCA-soluble fraction is determined at 660 nm using 200 μL of 25% (v/v) Folin-Ciocalteau reagent and 1 mL 0.5 M sodium carbonate. One unit of activity is defined as the amount of enzyme hydrolyzing casein to produce absorbance equivalent to 1.0 μmol of tyrosine per minute at 37° C. This result is converted to Units/cm2.
Enzyme loading is titered in coatings prepared and coated onto substrate panels as in Example 1 and with insect stains applied as in Example 2 at loading concentrations of enzyme of 0.2% (A), 2.0% (B), 4.0% (C), 6.0% (D), and 8.0% (E) active extracellular fragment of enzyme G. stearothermophilus TLP, and the thermolysin-like-proteins from Bacillis cereus, Lactobacillis sp., Bacillis megaterium, Alicyclobacillis acidocaldarious, Bacillis caldolyticus, Bacillis thermoproteolyticus, Bacillus stearothermophilus, Bacillus subtilis, Bacillus amyloliquefaciens), and Lysteria monocytogenes. The panels are baked for 5 min at 40° C. and washed at 300 RPM for three hours. Increased protease loading correlates with increased rinsing performance (
Comparison of various protease types on insect stain removal. Coatings are prepared as in Example 1 using protease N (bacillolysin) as a putative cysteine protease, Protin SD AY10 (subtilisin from Bacillus licheniformis) as a putative serine protease, protease A as an exemplary metalloprotease, and the active extracellular fragment of enzyme G. stearothermophilus TLP and thermolysin-like-proteins of Example 7, and coated onto substrates as in Example 1 with insect staining as in Example 2. The different enzyme containing coatings are compared after baking for 5 min at 40° C. and rinsing at 300 RPM for 3 hours. Surprisingly, only the active extracellular fragment of enzyme G. stearothermophilus TLP based coatings show the dramatically improved self-cleaning function which is not observed by coatings including, a serine protease, a cysteine protease, or another metalloprotease. (Table 5 and
Test panels are prepared as in Example 1 and are mounted onto the front bumpers of test vehicles. A schematic of a road-test protocol is illustrated in
Within three days of insect collection the panels are rinsed either in natural rain (driving condition) or in lab on a water bath at a rate of shaking rate of 200 rpm. Photos are taken prior to and after the rinsing procedure. Panels are visually checked and counted prior to, during, and after rinsing to identify differences in stain removal from test and control panels.
A clear increase in stain-removal effectiveness under mild rinsing is observed on enzyme-containing coatings relative to control coatings without enzyme as is illustrated in FIGS. 10 and 11. The road test is repeated three times and the average percent remaining insect stains in enzyme containing and control coatings after rinsing for various times are plotted in
Enzyme containing coatings are prepared as in Example 1 using buffers of pH 6.4 and pH 11. Coated aluminum plates are subjected to insect staining as in Example 9. Enzyme containing coatings prepared at both pH levels are superior to control (
Various cleaning fluids are analyzed for performance by measurement of average rinsing time using a standard protocol. For removal of insect stains by an active extracellular fragment of active extracellular fragment of enzyme G. stearothermophilus TLP containing cleaning fluid, the fluid is prepared as described in Example 1. Control cleaning fluids of Rain-X Bug Pre-wash Gel (Commercial Detergent 1), Rain-X Foaming Car Wash (Commercial Detergent 2), a sodium chloride solution, and water alone are compared. Insect material is applied onto a glass substrate dried on a heating plate at 60° C. for a period. After drying, drops of 50 μ1 enzyme containing cleaning fluids of Example 1 are added onto dry stain spots via a multi-channel pipette, followed by an incubation for 10 minutes at ambient temperature. The identical volume of control (protease free) washer fluids are added onto the control spots on the same substrate. The substrate is then immersed face-up into a deionized water bath while horizontally shaking at 100 rpm. The substrate is agitated for 1 hour and the time of each spot removal is recorded.
Similar experiments are performed using cleaning fluids prepared as in Example 1 with substitution of lipase (LIPASE PS), α-Amylase, or active extracellular fragment of G. stearothermophilus TLP (THERMOASE C160), or no enzyme. The experiments above are repeated with the exception that shaking in water is continued out to three hours. As illustrated in
A cleaning fluid containing the active extracellular fragment of enzyme G. stearothermophilus TLP with high pH demonstrates increased specific activity and excellent stability relative to the active extracellular fragment of enzyme G. stearothermophilus TLP containing fluids with lower pH. Various commercial enzyme free cleaning fluids (RAIN-X De Icer; PRESTONE BUG WASH; and EXTRME BLUE) and water are used as a base for the addition of the active extracellular fragment of enzyme G. stearothermophilus TLP using the procedure of Example 1. The protease containing cleaning fluids are stored at ambient temperature and assayed at various timepoints using the procedure of Example 11 for their ability to promote insect stain removal. As is illustrated in
Various modifications of the present invention, in addition to those shown and described herein, will be apparent to those skilled in the art of the above description. Such modifications are also intended to fall within the scope of the appended claims.
It is appreciated that all reagents are obtainable by sources known in the art unless otherwise specified or synthesized by one of ordinary skill in the art without undue experimentation. Methods of nucleotide amplification, cell transfection, and protein expression and purification are similarly within the level of skill in the art.
Patents and publications mentioned in the specification are indicative of the levels of those skilled in the art to which the invention pertains. These patents and publications are incorporated herein by reference to the same extent as if each individual application or publication was specifically and individually incorporated herein by reference.
The foregoing description is illustrative of particular embodiments of the invention, but is not meant to be a limitation upon the practice thereof. The following claims, including all equivalents thereof, are intended to define the scope of the invention.
Claims
1. A method of facilitating the removal of a biological stain on a substrate or a coating comprising:
- providing a liquid coating material;
- incorporating a polymer within the liquid coating material; and
- incorporating an enzyme into said liquid coating material to form a liquid bioactive coating material such that said enzyme is associable with the polymer and is capable of enzymatically degrading a component of a biological stain.
2. The method of claim 1 wherein the enzyme is a hydrolase.
3. The method of claim 1 wherein the enzyme is a lipase, a protease, or an amylase.
4. The method of claim 1 wherein the enzyme is a protease with a specific activity in excess of 20,000 U/g.
5. The method of claim 1 wherein the pH of the liquid coating material is greater than 8.0.
6. The method of claim 1 wherein said enzyme is in solution in said liquid coating material.
7. The method of claim 1 wherein said liquid coating material comprises an alcohol, said alcohol present at less than 0.8% by weight.
8. The method of claim 1 wherein said liquid coating material comprises ammonia, or a derivative of ammonia.
9. The method of claim 1 further comprising applying said bioactive coating material to a biological stain, thereby promoting removal of said stain.
10. The method of claim 9 wherein said biological stain is a food stain or an insect stain.
11. The method of claim 9 wherein said biological stain is present on a substrate.
12. The method of claim 1 wherein the polymer is one or more of aminoplasts, melamine formaldehydes, carbamates, polyurethanes, polyacrylates, epoxies, polycarbonates, alkyds, vinyls, polyamides, polyolefins, phenolic resins, polyesters, or polysiloxanes.
13. The method of claim 1 wherein the polymer includes a functional group of acetoacetate, acid, amine, carboxyl, epoxy, hydroxyl, isocyanate, silane, vinyl, or combinations thereof.
14. The method of claim 1 wherein the enzyme is non-covalently attached to the polymer.
15. A liquid composition for facilitating biological stain removal comprising:
- a liquid coating material;
- a polymer incorporated into the liquid coating material; and
- an enzyme incorporated into the liquid coating material and not covalently bound to the polymer.
16. The method of claim 15 wherein the enzyme is a lipase, a protease, or an amylase.
17. The method of claim 15 wherein the enzyme is a protease with a specific activity in excess of 20,000 U/g.
18. The composition of claim 15 wherein the pH of the sprayable composition material is greater than 5.0.
19. The composition of claim 15 wherein said enzyme is in solution in said liquid bioactive coating material.
20. The composition of claim 15 wherein said liquid bioactive coating material comprises an alcohol, said alcohol present at less than 0.8% by weight.
21. The composition of claim 15 wherein said liquid bioactive coating material is predominantly ammonia, or a derivative of ammonia.
22. The composition of claim 15 wherein the polymer is one or more of aminoplasts, melamine formaldehydes, carbamates, polyurethanes, polyacrylates, epoxies, polycarbonates, alkyds, vinyls, polyamides, polyolefins, phenolic resins, polyesters, or polysiloxanes.
23. The composition of claim 15 wherein the polymer includes a functional group of acetoacetate, acid, amine, carboxyl, epoxy, hydroxyl, isocyanate, silane, vinyl, or combinations thereof.
Type: Application
Filed: Jan 26, 2019
Publication Date: May 23, 2019
Inventors: Songtao Wu (Ann Arbor, MI), Hongfei Jia (Ann Arbor, MI), Masahiko Ishii (Okazaki City Aichi), Minjuan Zhang (Ann Arbor, MI)
Application Number: 16/258,561
