EP3543325A1

EP3543325A1 - Organic disinfecting agent

Info

Publication number: EP3543325A1
Application number: EP18162645.8A
Authority: EP
Inventors: Sanjeev SWAMY; Rene Dr. GÄlli
Original assignee: Green Impact Holding AG
Current assignee: Livinguard AG
Priority date: 2018-03-19
Filing date: 2018-03-19
Publication date: 2019-09-25
Also published as: WO2019180041A1

Abstract

A disinfecting agent comprising
- at least one amino acid and/or at least one iminosugar or a salt thereof, and
- polyglucosamine or a salt thereof,
wherein the mass ratio between the amino acid and polyglucosamine is 0.25:1-5:1 and wherein at most 1% of the amine groups of polyglucosamine are functionalized with the amino acid.

A cleaning agent, detergent, dish-washing detergent, or rinsing agent, comprising the disinfecting agent.
A method for the preparation of a disinfecting agent, comprising mixing the amino acid and/or the iminosugar in powder or liquid form and polyglucosamine in powder or liquid form, wherein at most 3% of the amino acid and/or polyglucosamine are activated with a cross-linking reagent.
A method for the reduction of microbial contamination in a liquid.
A method of sanitizing a surface.

Description

Field of the invention

The present invention relates to an organic disinfecting agent comprising at least one amino acid, at least one amino acid derivative and/or at least one iminosugar, and polyglucosamine. The disinfecting agent can be used for sanitizing surfaces or can be applied in combination with cleaning agents, such as detergents.

Background of the invention

Disinfectants are extensively used in everyday life to prevent microbial spread and microbial infections, such as in the health care sector, the food industry, agriculture, or in common household products.
However, one major problem arising from the extensive use of disinfectants is the continuous contamination of the environment with these disinfectants. Usually, disinfectants are provided in solution and applied directly onto contaminated surfaces, such as in hospitals or of laboratory equipment, or skin wounds. In case these disinfectants are not neutralized, such as by autoclaving, or cannot be easily neutralized, they finally accumulate in the waste water. Such contamination may ultimately result in the emergence of microbial strains that are resistant to commonly used antimicrobial agents.
Therefore, there is a need for an antimicrobial agent, which comprises environmentally friendly chemical agents. The agents are preferably natural, organic compounds. Such compounds are usually biodegradable, thereby reducing the risk of accumulation and contamination of the environment. The agents should be well tolerated by living tissues and could be used, for example, for sensitive applications such as preservative for food, as wound sanitizing agent or in combination with cleaning agents, for example detergents used in laundry machines. Moreover, the production of such antimicrobial agents should be cost-efficient, in particular in terms of the costs for the chemical agents used.

Brief description of the invention

The present invention solves the shortcomings of the state of the art by providing in a 1^st embodiment of the invention a disinfecting agent comprising

at least one amino acid, at least one amino acid derivative, and/or at least one iminosugar, and
polyglucosamine.

The inventors have found that common amino acids, peptides and quaternary ammonium comprising amino acid derivatives, or iminosugars can be combined with polyglucosamine (chitosan) to achieve a high antimicrobial activity. The at least one amino acid, amino acid derivative, iminosugar and/or polyglucosamine each carries at least one positive charge. Such positive charges are believed to adhere to the negatively charged membranes of microorganisms and to disrupt the membrane integrity, thereby acting biocidal.
According to a 2^nd embodiment, in the 1^st embodiment, at most 1%, preferably at most 0.8%, more preferably at most 0.1% of the amine groups of polyglucosamine are functionalized with the at least one amino acid, and/or amino acid derivative.
It was found that a complicated coupling of the amino acids or amino acid derivatives to polyglucosamine in terms of a peptide bond between the carboxy groups of the amino acids or amino acid derivatives and the amine groups of polyglucosamine is not required to achieve a high antimicrobial activity. Rather, the compounds may be simply combined in the antimicrobial agent without performing a crosslinking or condensation reaction. Further, it was found that an ester bond between the hydroxy groups of chitosan and carboxy groups of the amino acids and or amino acid derivates can be formed in an acidic solution, which allows that the amine groups of polyglucosamine, the amine groups of the amino acids and/or amino acid and potential further functional groups are non-functionalized and can carry positive charges, e.g. in a solution of neutral pH.
According to a 3^rd embodiment, in any one of the preceding embodiments, the polyglucosamine is non-animal derived.
For example, non-animal derived polyglucosamine can be isolated from fungi, such as mucorales.
According to a 4^th embodiment, in any one of the 1^st to 3^rd embodiment, the at least one amino acid is selected from the group consisting of natural amino acid, unnatural amino acid, non-proteinogenic amino acid, and/or wherein the at least one amino acid derivative is selected from the group consisting of peptide and quaternary ammonium comprising amino acid derivative.
According to a 5^th embodiment, in any one of the 1^st to 4^th embodiment, the amino acid and/or amino acid derivative has an isoelectric point equal to or above 7, preferably equal to or above 8, more preferably equal to or above 8.5, and/or has a pH-independent positive charge.
The use of amino acids and/or amino acid derivatives with an isoelectric point above 7 allows that the acids and/or amino acid derivatives carry a positive net charge at any pH value below the isoelectric point. Thus, the higher the isoelectric point, the larger is the range of pH values suitable for providing a positive net charge. Alternatively or in addition, amino acids or amino acid derivatives, such as quaternary ammonium comprising amino acid derivatives, may have a constant positive charge, which is pH independent. It has been found that a positive charge of the amino acid and/or amino acid derivative applied to the textile enhances the overall antimicrobial activity, in particular against gram-positive and gram-negative bacteria. Positive charges are believed to adhere to the negatively charged membranes of microorganisms and to disrupt the membrane integrity, thereby acting biocidal.
According to a 6^th embodiment, in any one of preceding embodiments, the natural, unnatural or non-proteinogenic amino acid is in L configuration, and/or wherein the peptide is an L-peptide.
The L-enantiomers of amino acids and peptides can be easily obtained from cultures, e.g. of E. coli, L. lactis or S. cerevisiae, rendering a complicated, cost-inefficient chemical synthesis unnecessary.
According to a 7^th embodiment, in any one of preceding embodiments, the amino acid is lysine, arginine, or histidine, preferably arginine.
The naturally occurring amino acids lysine, arginine, or histidine, in particular the L-enantiomers thereof, are environmentally friendly, as they can be obtained from common biological cultures. Moreover, these amino acids can be used as food additives or preservatives in the food industry, as they are non-toxic to living tissues. Arginine is one of the preferred amino acids because it is available at comparatively low costs.
According to an 8^th embodiment, in any one of preceding embodiments, the peptide is a dipeptide or a polypeptide, preferably wherein the polypeptide contains 3 to 50 amino acids.
According to a 9^th embodiment, in any one of preceding embodiments, the amino acid derivative is a lantibiotic, preferably wherein the amino acid derivative is nisin.
Nisin is commonly used as a food preservative, and, thus, can be also used for sanitizing packages or other products in the food industry.
According to a 10^th embodiment, in any one of preceding embodiments, the iminosugar is D-fagomine.
According to a 11^th embodiment, in any one of preceding embodiments, the amino acid derivative is carnitine or betaine.
Carnitine (in particular L-carnitine) and betaine are naturally occurring amino acid derivatives, which comprise quaternary ammonium groups that are positively charged in a pH-independent manner. In particular carnitine has proven to have an adequate antimicrobial activity in combination with polyglucosamine.
According to a 12^th embodiment, in any one of preceding embodiments, the disinfecting agent comprises arginine and carnitine.
The combination of arginine and carnitine, in particular L-arginine and L-carnitine, confers a particularly high antimicrobial activity, e.g. against both gram-negative and gram-positive bacteria.
According to a 13^th embodiment, in any one of preceding embodiments, polyglucosamine is essentially free of thiol groups.
"Essentially free" of certain groups or compounds in the context of the present invention means that the respective groups or compounds are comprised only as usual impurities, i.e. they are not added to the formulations of the present invention and/or the formulations of the present invention are not derivatized with the groups.
According to a 14^th embodiment, in any one of preceding embodiments, the disinfecting agent comprises at most 1.8%, preferably at most 1%, more preferably at most 0.5% of trehalose, most preferably at most 0.1% trehalose. In a most preferred embodiment, the disinfecting agent is essentially free of trehalose.
According to a 15^th embodiment, in any one of preceding embodiments, the disinfecting agent is a solution or suspension.
According to a 16^th embodiment, the disinfecting agent of any one of the preceding embodiments comprises at most 10%, preferably at most 5%, more preferably at most 2%, more preferably at most 1%, most preferably at most 0.5% of an organic solvent, based on the total amount of solvent.
For example, the organic solvents ethanol or isopropanol can be comprised in very low amounts, or the disinfecting solution can be essentially free of organic solvents, such as ethanol or isopropanol. Thereby, the disinfecting solution can be well tolerated during use, e.g. for cleaning the human skin.
According to a 17^th embodiment, in any one of preceding embodiments, the disinfecting agent comprises water as a solvent.
According to a 18^th embodiment, in any one of preceding embodiments, the water is the main solvent of the disinfecting agent.
It was found that the disinfecting agent can be prepared using mainly water as solvent, i.e. more than 50% of the solvent can be water. Preferably water is the only solvent in the disinfecting agent.
According to a 19^th embodiment, in any one of preceding embodiments, the disinfecting agent has a pH between pH 4 and pH 12, more preferably to between pH 6 and pH 11.5, even further preferably between pH 8 and pH 11, most preferably between pH 9 and pH 10.5.
It has been found that in particular in combination with anionic tensides, e.g. in a cleaning agent, a basic pH of the disinfecting agent improves the overall antimicrobial activity.
The inventors found that the disinfecting agent is in particular effective in its antimicrobial activity when the pH is adjusted to the indicated pH range and in particular to the indicated basic pH range.
According to a 20^th embodiment, in any one of preceding embodiments 1 to 14, the disinfecting agent is a powder.
According to a 21^st embodiment, in any one of preceding embodiments, the disinfecting agent comprises at most 10%, preferably at most 5%, more preferably at most 2%, further preferably at most 1%, most preferably at most 0.5% of a lyophilisate of polyglucosamine, based on the total weight of chitosan comprised in the disinfection agent. In a most preferred embodiment, the disinfecting agent is essentially free of a lyophilisate of polyglucosamine.
According to a 22^nd embodiment, in any one of the preceding embodiments, the polyglucosamine is provided in water-soluble form.
A water-soluble form of polyglucosamine can be provided by dissolving a powder or flakes comprising polyglucosamine in an acidic medium. By using a water-soluble form in the liquor, polyglucosamine can be well dispersed.
According to a 23^rd embodiment, in any one of the preceding embodiments, the mass ratio between the amino acid or the amino acid derivative and polyglucosamine is between 0.25:1 and 5:1, preferably between 0.5:1 and 3:1, more preferably between 1:1 and 2:1.
According to a 24^th embodiment, in any one of the preceding embodiments, the mass ratio between the amino acid and of the amino acid derivative together and polyglucosamine is between 2:1 and 5:1, preferably between 3:1 and 4:1.
According to a 25^th embodiment, in any one of the preceding embodiments, the disinfecting agent further comprises one, two, three, or all four antimicrobial agents selected from the group consisting of propiconazole, silver ions, polyhexamethylene biguanide, quaternary ammonium organosilane.
These antimicrobial agents are not biodegradable. In certain applications it may nevertheless be desirable to add them because they increase the overall antimicrobial activity of the disinfecting agent. The inventors found that these antimicrobial agents can be well combined with amino acids and/or amino acid derivatives, and polyglucosamine.
According to a 26^th embodiment, in any one of the preceding embodiments, quaternary ammonium organosilane is a hydrophilic quaternary ammonium organosilane, preferably an organomethoxysilane compound, more preferably N-trimethoxysilylpropyl-n,n,n-trimethylammonium chloride.
According to a 27^th embodiment, in any one of the preceding embodiments, the disinfecting agent comprises at least one organic acid, preferably selected from the group consisting of acetic acid, citric acid, lactic acid, formic acid and p-toluenesulfonic acid.
These acids can improve the solubility of polyglucosamine in the disinfecting agent.
According to a 28^th embodiment, in any one of the preceding embodiments, at least 90%, preferably at least 95%, more preferably at least 98%, even more preferably at least 99%, further preferably at most 99.9%, and most preferably about 100% of the disinfecting agent is made from a renewable raw material, and/or is biodegradable and/or natural and organic.
In a 29^th embodiment, the present invention is directed to a cleaning agent, such as a detergent, dish-washing detergent, or rinsing agent, comprising the agent of any one of the 1^st to 28^th embodiment.
According to a 30^th embodiment, in the 29^th embodiment, the cleaning agent comprises linear alkyl benzene sulphonate, linear alkyl benzene, a non-ionic tenside and/or an anionic tenside.
According to a 31^st embodiment, in the 29^th or 30^th embodiment, the cleaning agent comprises soap, glycerine, fats, and other components generally added to soaps.
In a 32^nd embodiment, the present invention is directed to a method for the preparation of a disinfecting agent according to any one of embodiments 1 to 28, comprising mixing the at least one amino acid, the at least one amino acid derivative and/or the at least one iminosugar in powder or liquid form and polyglucosamine in powder or liquid form.
According to a 33^rd embodiment, in the 32^nd embodiment, at most 3%, preferably at most 2%, more preferably at most 1%, most preferably at most 0.5% of the at least one amino acid, amino acid derivative and/or polyglucosamine are activated with a cross-linking reagent, in particular with a carbodiimide and/or a N-hydroxysuccinimide. In a most preferred embodiment, the amino acid, amino acid derivative and/or polyglucosamine are essentially free of a crosslinking reagent, in particular with a carbodiimide and/or a N-hydroxysuccinimide.
According to a 34^th embodiment, in the 32^nd or 33^rd embodiment, the at least one amino acid, amino acid derivative and/or imino sugar and polyglucosamine are mixed in a solvent, preferably water, to form a solution or suspension, preferably wherein the pH of the solution of suspension is adjusted to between pH 4 and pH 12, more preferably to between pH 6 and pH 11.5, even further preferably between pH 8 and pH 11, most preferably between pH 9 and pH 10.5.
According to a 35^th embodiment, in the preceding embodiment, the solution or suspension is stirred for at least 10 minutes, preferably at least 20 minutes, more preferably at least 30 minutes, at a temperature of at least 30 °C, preferably at least 40 °C, more preferably at least 50°C, and/or at a temperature of at most 70 °C, preferably at most 60 °C, more preferably at most 55°C.
The stirring/incubation step allows for a further increase in antimicrobial activity. The inventors believe that during incubation, polyglucosamine molecules react with the amino acid and/or amino acid derivate, such that an ester bond is formed. A temperature of the reaction mixture of at least 30 °C, more preferably at least 40 °C, even more preferably at least 50 °C, was found to foster the reaction in the incubation step.
In a 36^th embodiment, the present invention is directed to a method for the reduction of microbial contamination in a liquid, comprising applying to the liquid the disinfecting agent according to any one of embodiments 1 to 28 or the cleaning agent according to any one of embodiments 29 to 31.
According to a 37^th embodiment, in the preceding embodiment, the disinfecting agent or the cleaning agent is added into a washing machine in the course of a laundry cycle for washing one or more textile products.
According to a 38^th embodiment, in the preceding embodiment, the disinfecting agent or the cleaning agent is added together with a washing detergent into the washing machine, preferably wherein the disinfecting solution is comprised in the washing detergent.
According to a 39^th embodiment, in the preceding 37^th embodiment, the disinfecting agent or the cleaning agent is added into the washing machine at a rinsing step, such that the disinfecting solution remains partially adhered to the one or more textile products at the end of the laundry cycle.
According to a 40^th embodiment, in any one of the 36^th to 39^th embodiment, the disinfecting agent or the cleaning agent is applied to the liquid, such that the liquid comprises 0.001 to 1% by weight, preferably 0.002 to 0.5% by weight polyglucosamine, 0.001 to 1% by weight, preferably 0.01 to 0.5% by weight the amino acid, 0.001 to 1% by weight, preferably 0.01 to 0.5% by weight the amino acid derivative, and/or 0.001 to 1% by weight, preferably 0.002 to 0.5% by weight the iminosugar.
According to a 41^st embodiment, in any one of the 36^th to 40^th embodiment, after 1 hour of incubation, preferably after 30 minutes of incubation, more preferably after 10 minutes of incubation, the reduction of antimicrobial contamination in the liquid is at least 90%, preferably at least 99%, more preferably at least 99.9%, most preferably at least 99.99%, when measured in accordance with the ASTME-2149 test method against P. aeruginosa, Staphylococcus aureus and/or E. coli.
In a 42^nd embodiment, the present invention is directed to a method of sanitizing a surface, in particular a surface contaminated with microbes, comprising applying to the surface a disinfecting agent according to any one of embodiments 1 to 28 or a cleaning agent according to any one of embodiments 29 to 31.
According to a 43^rd embodiment, in the preceding embodiment, the disinfecting agent or cleaning agent is applied to the surface in the course of cleaning the surface, in particular by wiping, rinsing, or mopping and/or with the help of a wipe, towel, or mop.
According to a 44^th embodiment, in the preceding embodiment, the surface is living human or animal skin, preferably skin of the human hand or face, or the surface is a floor, a kitchen top, a table, a medical device, furniture, in particular in an operating theater or emergency room, a door handle, a dish, cutlery, a steering wheel, a keyboard, bathroom surface, vehicle surface, a surface in a restaurant or hotel, a wall, or an electrical consumer product.
According to a 45^th embodiment, in any one of the 42^nd to 44^th embodiments, the disinfecting agent is applied such that 0.001 to 1% by weight, preferably 0.01 to 0.5% by weight polyglucosamine, 0.0002 to 1% by weight, preferably 0.01 to 0.5% by weight the amino acid, 0.001 to 1% by weight, preferably 0.01 to 0.5% by weight the amino acid derivative, and/or 0.001 to 1% by weight, preferably 0.002 to 0.5% by weight the iminosugar are applied to the surface.
According to a 46^th embodiment, in any one of the 42^nd to 45^th embodiments, after 1 hour of incubation, preferably after 30 minutes of incubation, more preferably after 10 minutes of incubation, the reduction of antimicrobial contamination on the surface is at least 90%, preferably at least 99%, more preferably at least 99.9%, when measured in accordance with the ASTME-2149 test method against P. aeruginosa, Staphylococcus aureus and/or E. coli.
All percentages hereinafter refer to weight unless otherwise indicated. "gpl" or "GPL" stands for "grams per liter". "R.t." or "RT" stands for "room temperature", which is a temperature in the range of 15 to 35 °C.
The term "antimicrobial" as used in the context of the present invention relates to the ability to kill at least some types of microorganisms, or to inhibit the growth or reproduction of at least some types of microorganisms. Said term relates to any compound, agent, product or process that is harmful to one or more "microorganism" as used in the context of the present invention. Preferably, the one or more "microorganism" gets killed by the "antimicrobial" product or process.
The term "antimicrobial agent" as used herein means any chemical compound that acts antimicrobial against at least some types of microorganisms. Exemplary antimicrobial agents are chitosan, quaternary ammonium organosilane, silver cations, polyhexamethylene biguanide (PHMB), propiconazole, amino acids, amino acid derivatives, and iminosugars.
The terms "microorganism" and "microbe", which are used interchangeably in the context of the present invention, are defined to comprise any organism too small to be seen by the unaided eye, such as, especially, single-celled organisms. In particular, the terms "microorganism" and "microbe" cover prokaryotes including bacteria and archaea, eukaryotes including protists, animals like dust mites or spider mites, fungi, and plants like green algae, as well as viruses.
The term "biodegradable" as used herein refers to any form of textile, amino acid, amino acid derivative, chitosan, antimicrobial agent or other chemical compounds, which can be decomposed by living cells, such as bacteria.
The term "natural and organic" as used herein refers to organic compounds that may by produced by living organisms. For example, all amino acids that are synthesized by biological cells or chitosan are natural and organic compounds.

Detailed description of the invention

Preferred embodiments and examples of the invention will be described in the following detailed description. It is emphasized, however, that the present invention is not limited to these embodiments.
The present invention relates to a natural and organic disinfecting agent. Advantageously, the agent comprises naturally occurring functional agents, such as amino acids or peptides, in combination with chitosan.
The disinfecting agent is environmentally friendly, as the antimicrobial agents, such as natural amino acids, are biodegradable. Moreover, the use of amino acids and/or amino acid derivatives as antimicrobial agents lowers the production costs for the production of the antimicrobial agent, e.g. in comparison to antimicrobial agents comprising chitosan only.

Functional agents:

The antimicrobial agent comprises at least one amino acid, amino acid derivative and/or iminosugar, and chitosan.
Both the amino acid and the amino acid derivative contain at least two functional groups, one of them being a carboxy group, and the other one being an amine group or quaternary amine group. Unless otherwise indicated, the carboxy group and the amino group are not derivatized, e.g. with crosslinking agents. The amino acid may be an alpha-amino acid, as represented by the following structural formula:
In other embodiments, the amino acid may be a beta-, gamma- or delta-amino acid.
The exemplary proteinogenic amino acid L-arginine is represented by the following structural formula:
The exemplary non-proteinogenic amino acid derivative L-carnitine is represented by the following structural formula:
Chitosan has a structure as shown hereinafter, wherein n indicates the number of monomer units as known in the art:
Nisin is a lantibiotic with the following structure:
D-fagomine is a iminosugar with the following structure:
When the amino acids and/or amino acid derivatives are used in combination with chitosan, under the reaction conditions disclosed herein, R'-COOH groups of amino acids and/or amino acid derivatives may react with R"-OH groups of chitosan by forming an ester bond R'-COO-R'.

Examples

The invention will be further described by the following examples which illustrate the preparation of disinfection agents, without limiting the invention.

ASTME-2149 test method for antimicrobial performance:

Antimicrobial performance of disinfecting agents according to the invention were performed following the ASTME-2149 test method.
Briefly, the test bacteria (E. coli, S. aureus, P. aeruginosa) were cultured in liquid culture and adjusted to 10⁷ CFU/ml in PBS buffer in cell culture flasks, as specified in the examples (volume: 51 or 101 ml). In some examples, the buffer further comprised a detergent as indicated. To the flasks, 5 µl to 2.5 ml of the antimicrobial agent, as indicated in the examples, were added to obtain the total test volume, and the flasks were shaken for 1 hour. Optionally, 0.3% bovine serum albumin (BSA) was added to the flasks, as indicated in the examples. After incubation, the log reduction over the initial time point was determined.
The Log Reduction (R) of bacteria was calculated by:

B [log(number bacteria recovered from the inoculated flask immediately after inoculation, i.e. at 0 contact time)] - A [log(number of bacteria recovered from the inoculated flask incubated over the desired contact period (1 hour))].

Chemicals

The following chemicals were or can be used:

L-arginine is known in the art and commercially available, e.g. by Sciencelab. In the following examples, L-arginine is provided as a powder with 100% by weight.
L-carnitine was provided by Lonza Specialty Chemicals Switzerland as a powder with > 98% by weight.

Chitosan (8% solution) was provided by Goyen Chem, Taiwan.
Propiconazole is known in the art and commercially available, e.g. Utconazol (manufactured by Utpan Chempro). Propiconazole can be bound to the textile material using a crosslinking agent, in particular a preferably blocked isocyanate compound, which results in urethane bonds, or an acrylate based-product. When using propiconazole, it is preferred to use a crosslinking agent in the liquor, in particular the exhaust liquor. It is even more preferred that the formulation of propiconazole contains the cross linking agent or the cross-linking agent is part of the propiconazole formulation. In the following examples, propiconazol (Utpan Chempro) was provided as a 25% stock solution.
The quaternary ammonium organosilane can comprise an organomethoxysilane, preferably N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride, as provided by Gelest Inc. as a 50% stock solution.
Polyhexamethylene biguanide is known in the art and commercially available. In the following examples, polyhexamethylene biguanide (PHMB, Thor GmbH) was provided as a 20% stock solution.
An antimicrobial agent can comprise silver cations. In particular embodiments, the silver cations are trapped in an inorganic or organic matrix. Preferably, the inorganic matrix is an aluminosilicate. Preferably, the organic matrix is a polymeric matrix. Such silver-containing microbial agents are known in the art and available on the market. In the following examples, Silvadur 930 Flex (0.1% silver cations trapped in a polymeric matrix) was provided by Dow Chemical Company.
As a cross-linker, blocked polyisocyanate, e.g. oxime-blocked polyisocyanate, can be used. Oxime-blocked polyisocyanate is, for example, provided by Schoeller Technologies AG.

Example 1

A disinfecting agent according to the invention was prepared by mixing

100 gpl chitosan solution (8% stock solution; i.e. 8 gpl chitosan)
35 gpl L-arginine
35 gpl L-carnitine

The disinfecting agent was added to 51 ml cell culture in PBS and tested according to ASTME-2149, as described above, with test parameters as compiled in Table 1.

Table 1: Antimicrobial performance of different concentrations of the disinfecting agent

Sample ID	neg. control	0.01%	0.05%	0.10%	0.5%	1%	2%	3%	4%	5%
Volume of disinfecting agent	0	5 µL	25 µL	50 µL	250 µL	0.5 ml	1 ml	1.5 ml	2 ml	2.5 ml
Total test volume	51 ml	51.005 ml	51.025 ml	51.05 ml	51.25 ml	51.5 ml	52 ml	52.5 ml	53 ml	53.5 ml
Concentration of disinfecting agent in total test volume	0%	0.01%	0.05%	0.10%	0.5%	1%	2%	3%	4%	5%
Detergent	Triton X-100 (0.06%)	Triton X-100 (0.06%)	Triton X-100 (0.06%)	Triton X-100 (0.06%)	Triton X-100 (0.06%)	Triton X-100 (0.06%)	Triton X-100 (0.06%)	Triton X-100 (0.06%)	Triton X-100 (0.06%)	Triton X-100 (0.06%)

Log reduction (ASTME 2149)
P. aeruginosa	0.03	0.98	1.56	2.81	4.57	5.24	5.24	5.24	5.24	5.24
E. coli	0.02	0.93	1.44	2.94	4.67	5.38	5.38	5.38	5.38	5.38
S. aureus	nd	nd	nd	nd	nd	5.55	5.85	5.85	5.85	5.85

As can be derived from the above table 1, concentrations of the antimicrobial agent of at least 0.5% confer high antimicrobial activity of at least log 4, i.e. > 99.99% bacterial reduction. The use of the disinfecting agent in a concentration of between 0.5% and 1% is also of economic interest, as the costs for the production and application are reasonable.
Moreover, the results show that the disinfecting agent can be combined with a nonionic detergent, such as Triton X-100 (Octoxynol 9), e.g. in a cleaning agent.

Example 2

A disinfecting agent according to the invention was prepared by mixing

100 gpl chitosan solution (8% stock solution; i.e. 8 gpl chitosan)
35 gpl L-arginine and/or 35 gpl L-carnitine

table 2.

Table 2: Preparation of disinfecting agents with varying concentrations and pH values

Sample ID	1	2	3	4	5	6	7	8
Chitosan (gpl)	100	100	100	100	100	100	100	100
L-arginine (gpl)	0	35	35	35	0	0	0	35
L-carnitine (gpl)	35	35	35	35	35	35	35	35
pH	5.51	4.58	4.5	4.51	4.51	4.51	4.51	10.1
pH adjusting chemical	-	Acetic acid	Formic acid	Lactic acid	Acetic acid	Formic acid	Lactic acid	-
pH adjusting chemical (gpl)	-	22	18	24	2	1.8	2.5	-
Incubation temperature	R.T.	50°C	50°C	50°C	50°C	50°C	50°C	R.T.
Incubation time (stirring)	10 min	10 min	10 min	10 min	10 min	10 min	10 min	10 min

Each disinfecting agent was added to 101 ml cell culture in PBS and tested according to the ASTME 2149 test method as described above. The total test volume further comprised 0.3% BSA and 0.15% of the detergent "Surf Excel Quickwash powder". Surf Excel comprises anionic detergents. The test parameters and results are summarized in Table 3.

Table 3: Antimicrobial performance of samples 1 to 7 in Surf Excel

Sample ID	1	2	3	4	5	6	7	Negative control
Volume of disinfecting agent	0.5 ml	0.5 ml	0.5 ml	0.5 ml	0.5 ml	0.5 ml	0.5 ml	0.5 ml distilled water
Total test volume	101.5 ml	101.5 ml	101.5 ml	101.5 ml	101.5 ml	101.5 ml	101.5 ml	101.5 ml
Concentration of disinfecting agent in total test volume	0.5%	0.5%	0.5%	0.5%	0.5%	0.5%	0.5%	0.5%
Detergent	Surf Excel 0.15%	Surf Excel 0.15%	Surf Excel 0.15%	Surf Excel 0.15%	Surf Excel 0.15%	Surf Excel 0.15%	Surf Excel 0.15%	Triton X-100 0.15%
BSA	0.3%	0.3%	0.3%	0.3%	0.3%	0.3%	0.3%	-

Log reduction (ASTME 2149)
E.coli	1.15	1.49	1.5	1.28	1.49	1.78	1.03	0.49
S.aureus	5.32	5.64	5.4	5.33	5.61	5.9	5.61	nd

As can be derived from the above table 3, the disinfecting agents 1 to 7, applied in a concentration of about 0.5%, have a particularly high antimicrobial activity of more than log 5 (>99.999 reduction) against the gram-positive bacterium S. aureus, even in combination with the anionic washing detergent Surf Excel.
Also, the antimicrobial activity of the disinfecting agent was tested with respect to the pH of the disinfecting agent. The ASTME 2149 test was conducted as described in the following table 4.

Table 4: Antimicrobial performance of samples 2 and 8 in Surf Excel

Sample ID	2	2	8
Volume of disinfecting agent	1 ml	2 ml	1 ml
Total test volume	102 ml	103 ml	102 ml
Concentration of disinfecting agent in total test volume	1%	2%	1%
Detergent	Surf Excel 0.15%	Surf Excel 0.15%	Surf Excel 0.15%
BSA	0.3%	0.3%	0.3%

Log reduction (ASTME 2149)
E.coli	1.23	1.24	4.8
S.aureus	4.29	4.42	5.9
P. aerogunosa	3.4	3.56	4.5

As can be derived from table 4, the antimicrobial performance was increased, in particular against E. coli, if the pH of the disinfecting agent was basic, cf. Sample ID 8. The improved activity of the disinfecting agent at basic pH values even outcompetes a increases concentration of the disinfecting agent at a lower pH value.

The antimicrobial agents were also tested according to the ASTME 2149 test method as described above, using no detergent in the test flasks, as summarized in Table 5.

Table 5: Antimicrobial performance of samples 1 to 7 without detergent

Sample ID	1	2	3	4	5	6	7	Negative control
Volume of antimicrobial agent	0.5 ml	0.5 ml	0.5 ml	0.5 ml	0.5 ml	0.5 ml	0.5 ml	0.5 ml distilled water
Total Liquid	101.5 ml	101.5 ml	101.5 ml	101.5 ml	101.5 ml	101.5 ml	101.5 ml	101.5 ml
Concentration of disinfecting agent in total test volume	0.5%	0.5%	0.5%	0.5%	0.5%	0.5%	0.5%	0.5%
Detergent	-	-	-	-	-	-	-	-
BSA	0.3%	0.3%	0.3%	0.3%	0.3%	0.3%	0.3%	-

Log reduction (ASTME 2149)
E.coli	3.61	4.37	4.37	3.76	3.64	3.84	3	0.13
S.aureus	2.04	2.6	2.67	2.3	2.37	2.38	1.86	-0.05

As can be derived from table 5, also in the absence of any detergent, the disinfecting agents 1 to 7 confer a high protection against gram-positive and gram-negative bacteria.

Example 3

A disinfecting agent according to the invention was prepared by mixing

100 gpl chitosan solution (8% stock solution; i.e. 8 gpl chitosan)
70 gpl L-arginine and 70 gpl L-carnitine

table 6.

Table 6: Preparation of disinfecting agents with varying pH values

Sample ID	9	10
Chitosan (gpl)	100	100
L-arginine (gpl)	70	70
L-carnitine (gpl)	70	70
pH	10.44	4.87
pH adjusting chemical	-	Acetic acid
pH adjusting chemical (gpl)	-	36
Incubation temperature	R.T.	R.T.
Incubation time (stirring)	10 min	10 min

The antimicrobial agents were also tested according to the ASTME 2149 test method as described above, using Triton X-100 in the test flasks, as summarized in Table 7.

Table 7: Antimicrobial performance of samples 9 and 10 in non-ionic detergent

Sample ID	9	10
Volume of antimicrobial agent	0.5 ml	0.5 ml
Total Liquid	101.5 ml	101.5 ml
Concentration of disinfecting agent in total test volume	0.5%	0.5%
Detergent	Triton X-100 (0.06%)	Triton X-100 (0.06%)

Log reduction (ASTME 2149)
E.coli	6.02	1.78
S.aureus	5.34	3.14

In view of the results shown in table 7, the improved activity of the disinfecting agent at basic pH values was confirmed also when used in combination with the nonionic detergent Triton X-100. Specifically, the disinfecting agent of Sample ID 9 of table 6 at a pH of 10.44 was compared to the same agent but at a pH of 4.87 (Sample ID 10). The activity of the disinfecting agent at a pH 10.44 increased for E. coli from log 1.78 to 6.02 and for S. aureus still from 3.14 to 5.34.

Claims

A disinfecting agent comprising
- at least one amino acid, at least one amino acid derivative, and/or at least one iminosugar or a salt thereof, and

- polyglucosamine or a salt thereof,
wherein the mass ratio between the amino acid or the amino acid derivative and polyglucosamine is between 0.25:1 and 5:1, preferably between 0.5:1 and 3:1, more preferably between 1:1 and 2:1,
and wherein at most 1%, preferably at most 0.8%, more preferably at most 0.1% of the amine groups of polyglucosamine are functionalized with the at least one amino acid and/or amino acid derivative.
The disinfecting agent of claim 1, wherein the at least one amino acid is selected from the group consisting of natural amino acid, unnatural amino acid, non-proteinogenic amino acid, and/or wherein the at least one amino acid derivative is selected from the group consisting of peptide and quaternary ammonium comprising amino acid derivative.
The disinfecting agent of claim 1 or 2, wherein the amino acid and/or amino acid derivative has an isoelectric point equal to or above 7, preferably equal to or above 8, more preferably equal to or above 8.5, and/or has a pH-independent positive charge.
The disinfecting agent of any one of the preceding claims 1 to 3, wherein the amino acid is lysine, arginine, or histidine, preferably arginine; and/or wherein the amino acid derivative is a lantibiotic, preferably wherein the amino acid derivative is nisin; and/or wherein the iminosugar is D-fagomine.
The disinfecting agent of any one of the preceding claims 1 to 4, wherein the amino acid derivative is carnitine or betaine.
The disinfecting agent of any one of the preceding claims 1 to 5, wherein the disinfecting agent has a pH between pH 4 and pH 12, more preferably to between pH 6 and pH 11.5, even further preferably between pH 8 and pH 11, most preferably between pH 9 and pH 10.5.
The disinfecting agent of any one of the preceding claims 1 to 6, wherein the disinfecting agent is a solution or suspension.
The disinfecting agent of claim 7, comprising water as a solvent.
The disinfecting agent of any one of the preceding claims 1 to 6, wherein the disinfecting agent is a powder.
The disinfecting agent of any one of the preceding claims 1 to 9, wherein the mass ratio between the amino acid and of the amino acid derivative together and polyglucosamine is between 2:1 and 5:1, preferably between 3:1 and 4:1.
The disinfecting agent of any one of the preceding claims 1 to 10, further comprising one, two, three, or all four antimicrobial agents selected from the group consisting of propiconazole, silver ions, polyhexamethylene biguanide, quaternary ammonium organosilane.
A cleaning agent, detergent, dish-washing detergent, or rinsing agent, comprising the disinfecting agent of any one of claims 1 to 11.
A method for the preparation of a disinfecting agent according to any one of claims 1 to 11, comprising mixing the at least one amino acid, the at least one amino acid derivative and/or the at least one iminosugar in powder or liquid form and polyglucosamine in powder or liquid form,
wherein at most 3%, preferably at most 2%, more preferably at most 1%, most preferably at most 0.5% of the at least one amino acid, amino acid derivative, and/or polyglucosamine are activated with a cross-linking reagent, in particular with a carbodiimide and/or a N-hydroxysuccinimide.
A method for the reduction of microbial contamination in a liquid, comprising applying to the liquid the disinfecting agent according to any one of claims 1 to 11 or the cleaning agent according to claim 12.
A method of sanitizing a surface, in particular a surface contaminated with microbes, comprising applying to the surface a disinfecting agent according to any one of claims 1 to 11 or a cleaning agent according to claim 12.