FI115502B - Prevention of deposition caused by bacteria on surfaces of paper and cardboard machines - Google Patents

Description

115502

BACKGROUND OF THE INVENTION The invention relates to a method for preventing or preventing the formation of cartilage on surfaces of a thermophilic bacterium, Deinococcus geothermalis.

Field of the Invention and Prior Art

Special chemicals, microbicides, are used to prevent the growth of paper and board machines in their process waters 10 and to control the growth of harmful microbes on their surfaces. These must be pre-approved. Surface detachments that cause breakages and downtime include harmful bacteria as well as other bacteria, fibers, fibrils, resin, pigments and other papermaking materials. This bacterial build-up is also called biofilm. According to recent studies (M. Kolari, J. Nuutinen and MS Sal-kinoja-Salonen, Mechanism of Biofilm Formation in a Bacillus Species: The Role of Deinococcus Geothermalis, Journal of Industrial Microbiology & Biotechnology (2001) 27, p. 343- 351) One of the key factors in the accumulation is the so-called. primary infectious bacterium (Deinococcus geothermalis), which can: t ** 20 initiate accumulation. This bacterium is found quite commonly on paper machines. By preventing this bacterium from sticking to the steel surfaces, it is therefore intended to reduce the build-up of the machine, which is detrimental to the runnability of paper machines.

U.S. Patent No. 6,267,897 B discloses a method for preventing biofilm formation in commercial and industrial aqueous systems by adding essential oil therein. Examples of water systems include: cooling waters, food industry waters, pulp and paper mill systems, beer tanks - ;;; pasteurisers, freshwater systems, etc. This patent publication describes the experiment on glass surfaces of the mucus forming bacterium Sphaerotilus natans commonly found in paper mills. The results ....: 30 show that eucalyptus oil, cinnamon tree oil and tea tree oil more effectively inhibit the bacterial adhesion of the studied bacterium to the glass surfaces than the reference compound: a copolymer of ethylene oxide and propylene oxide. According to this patent, 1: Especially preferred essential oils are eucalyptus oil and cinnamon tree oil, which are commercial herbal preparations known to be produced by steam distillation. The other commercial essential oils mentioned in this patent specification are produced by steam distillation or compression.

S. natans is not present in modern, hot paper machines because it is unable to grow at temperatures of 50-60 ° C. Instead, the real problem bacterium 5 in today's papermaking machines is Deinococcus geo-Thermalis growing at high temperatures (max. 56-57 ° C). Studies have shown that essential oils are not at all capable of preventing the build-up of the problem bacterium Deinococcus geothermalis (see below). example 2).

From WO-A1-00 / 26466 preparations are known which can be used in closed or partially closed water systems, such as circulating waters of paper machines, for controlling mucus germs. The preparations are made from germinating or reproductive plant material.

It is known from WO-A1-00 / 59834 to prevent microbes from attaching to the surfaces of aqueous systems, such as those of papermaking aqueous systems. This is achieved by adding to the water systems a flavanol compound obtained from tea. The following microbes are mentioned in this publication: Pseudomonas, Klebsiella, Aerobacter, Acinetobacter, Enterobacter and Flavobacterium

WO-A2-01 / 68530 discloses a method for reducing the formation of mucus and deposits in closed or partially closed water systems such as '· 1' in circulating waters of a papermaking machine by the addition of sulfur-free lignin derived from pulp: or soda-anthraquinone method) from black liquor si- by acidification.

WO-A1-02 / 078450 discloses a method for controlling microbes in aqueous systems such as papermaking systems by adding hopic acid to the aqueous system.

EP-A1-778 244 discloses a method for preventing microbial mucus formation in industrial aqueous systems such as papermaking systems by adding tea extract or tannin or a copolymer of tannin and cationic monomer to the aqueous system. According to the publication, the microbe to be controlled is mainly Pseudonomas aeruginosa or Klebsiella pneumoniae.

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The present invention specifically seeks to prevent the build-up of a true problem bacterium D. geothermalis growing at high temperatures (about 50-60 ° C) in today's papermaking machinery.

It is therefore an object of the present invention to provide a process and a substance used therein which can effectively prevent the formation of a thermophilic Deinococcus geothermalis on the surfaces of paper or board machines.

DESCRIPTION OF THE INVENTION

It has now been found that certain organic plant extracts and certain herbal substances (betulin and flavonols) can prevent the formation of harmful deposits on paper and board machines by interfering with the adhesion of the actual problem bacteria to the surfaces of piping and wet sections. The use of these agents can reduce breaks and downtime caused by build-up and release on paper and board machine surfaces, provided they are not prevented. Laboratory studies have shown that plant extracts effectively (91-99.7%) inhibit the adhesion of an important factor, Deinococcus geothermalis, to paper machine steel surfaces (A1SI 316). The herbal substances studied (betulin and flavonols) inhibit the adherence of said deinococcus to steel to varying degrees (84-99.95%), depending on the substance.

Thus, according to the invention, there is provided a method of preventing or removing the build-up of thermophilic adhesive-20 by Deinococcus geothermalis on paper or board machine surfaces, characterized in that paper or board machine adding to the thermophilic contagious bacterium Deinococcus geothermalis effective '. * ·· content of at least one plant extract derived from one of the following plants; 25 or parts of plants: hardwood, coniferous bark, decayed coniferous or quince plant, or at least one herbal substance that is betulin or flavonol, such as pentahyde:. roxiflavone or trihydroxiflavone, or said plant extract and said plant extract. · · ·. grease mixture.

Examples of suitable hardwoods are rowan, birch, maple and willow. Examples of ·: ··· 30 suitable toad plants are lingonberry and blueberry. Said softwood bark is .. preferably pine bark and said decayed softwood is preferably deciduous branches.

Said plant extract is obtained by extraction of the plant or plant part with a suitable solvent or mixture of solvents. A preferred solvent is ethanol or acetone or a mixture thereof. When using a mixture of ethanol and acetone, the volume ratio of ethanol to acetone may be between 99: 1 and 1:99, preferably between 95: 5 and 5: 95. Other solvents suitable for extraction are methanol, hexane and chloroform. Mixtures of the solvents disclosed herein may also be used.

Said herbal agent, as well as said plant extract, must have the ability to inhibit the formation of the thermophilic bacterium Deinococcus geothermalis on the surfaces and / or the ability to remove such deposits from the surfaces.

Said herbal agent is betulin or flavonol such as pentahydroxyflavone or trihydroxyflavone or a mixture thereof. Betulin is present in birch blossoms and 10 flavonols can be obtained from flowering plants. These agents can also be prepared synthetically.

The plant extract or herbal substance or mixture thereof is added to the circulation water of paper or board machines at a product concentration of 1-1000 ppm, preferably 10-500 ppm and particularly preferably 20-250 ppm based on the dry weight of the plant extract or herbal substance.

The plant extract or herbal substance or mixture thereof may be dosed into the circulating water of paper or board machines either periodically 2 to 8 times daily or in a single dose daily.

The plant extract or herbal substance or mixture thereof may also be administered in high doses of 500-5000 ppm based on the dry weight of the plant extract or herbal substance in a container for removing so called "sticky" bacteria from its surfaces. shock dosing: lun.

According to the invention, crude extracts or * * · from said plants can be used. * more powerful components separated from these crude extracts.

,:. The invention also relates to said plant extract or said herbal substance, yeast, · · *. kaulin or flavonol, or a mixture thereof, to prevent or remove the build-up of the thermophilic adhesive bacterium Deinococcus geothermalis on paper or board machines, or to remove such deposits on said surfaces.

The invention will now be described in more detail by means of laboratory studies and examples. The percentages of dry solids shown in this specification are by weight and and are by volume of solvents.

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Studies carried out

Raw extracts of rowan, birch, willow, maple and spruce were made from chopped twigs (size 0.5-2 cm). The pine bark was minced before extraction to a similar size. Lingonberry and blueberry were extracted from the terrestrial part of the coats. The extractions were performed with a mixture of about 90% ethanol and about 3% acetone (solvent Etax B7) at room temperature for about 2 weeks. The extracts were concentrated to a dry solids content of 11-30%. The growth concentrations mentioned in the examples refer to the dry extract content of the crude extract.

The adhesive bacterium D. geothermalis isolated from a paper machine was stored frozen at -70 ° C. For anti-accumulation studies, it was rejuvenated in TH nutrient broth at 45 ° C with shaking. The composition of TH broth was as follows:

Tryptoni 5 g / l

Yeast extract 2.5 g / l

Water 1000 mL 15 pH 6.8-7.0

A total of 3 inocula (a "40 ml / day) of deoxygenated deinococcus were added to steel biofilm devices having a liquid volume of about 4 liters. Such biofilm devices are described in patent publication FI 95597. 20 0.1% papermaking machine tap water (peanutric broth for pentahydroxyflavone testing) circulated in steel (AISI 316) biofilm devices past sample plates (7.5 x 1, 5 cm) with pumps at approximately 60 cm / s. about 45 ° C. The acidity value was maintained at pH 6-7.5, 8 identical biofilm devices were used, one of which was used as a control (deinococcus alone) and the other 7 was used to test the efficacy of plant extracts and herbal substances (deinococcus + test substance). A total of 3 doses of test substances (30-500 ppm / day as dry substance) were added for a test period of 3 days. the inoculum content was determined from steel plates. · · ·. cultivation method. Loose deposits of steel sheets taken from biofilm devices were first removed for 2-3 s using sterile spray water (3 bar). Thereafter, the actual * * * ... · 30 deposits were removed with sterile toothbrushes in sterile water. From the suspensions thus obtained, deinococci were determined by culturing a filter membrane method; (0.2 µm, Sartorius) on PCA agar, incubation for 3 days at 45 ° C. PCA agar ',; the composition was as follows: 6 115502

Tryptoni 5 g / l

Yeast extract 2.5 g / l

Glucose 1 g / l

Agar 15 g / L Water 1000 ml pH 7.0

The steel plate of the control device had a deinococcal content of 105-107 pcs / cm2. The efficacy of the plant extract and herbal substances was obtained by comparing the deinococcal content (pc / cm2) of the control steel sheet with the deinococcal content (pc / cm) of the 10 steel sheets of the biofilm device containing the plant extract or herbal substance. This difference is expressed in percentages in the following examples.

eXAMPLES

Example 1

The efficacy of a plant extract (13% dry matter) of rowan to prevent deinococcal infestation was investigated in the laboratory with steel biofilm devices according to the method described above. The results were as follows:

Plant extract and dose Deinococcal content Deinococcus on steel sheet pc / cm_Inhibition% | Check 1.4x106 20 Pihlava New 100 ppm l.9x105 86: Pihlava New 250 ppm_4.4x103_99.7

From the results it can be seen that rowan extract at 100-250 ppm was quite effective in preventing the adhesion of deinococcus to steel, especially considering the high concentration of deinococci to be controlled in biofilm circulating water 25 (1x108-5x108 pcs / ml) dosing frequency (1 dose / day).

'· ·. Example 2: "1: The efficacy of other plant extracts was investigated in a manner similar to that of rowan extract, ..: in the previous Example 1. The results were as follows:» · · 7 115502

Plant Extract Plant Extract Plant Extract Deinococcal Solids Increase Inhibition% ppm%

Birch1 30 50 97.3 5 ”100 96.7 150 99.1

Spruce branches2 22 100 98.7

Lingonberry 26,250 94.8

Maple 13 100 92 10 ”250 97.2 Pine bark 25 50 97.6

Willow 11 100 91.1 ”250 98.2” 500 98.1 15 Blueberry 14_500_95 l = from dried birch twigs 2 = about 10 years from deciduous spruce branches

From the results, it can be seen that all plant extracts of Example 2, at sufficient concentrations, prevented the adherence of the deinococcus to the steel. The most effective were extracts of birch 20 and pine bark, which prevented the adhesion of deinococcus at about 97% at 50 ppm (as dry matter). Blueberry extract was required to obtain 500 ppm of the corresponding result.

Example 3 'The ability of herbal substances (betulin, pentahydroxyflavone and trihydroxyflavone) to inhibit the adhesion of deinococcus to paper machine blades was investigated in the same way as the ability of plant extracts in Examples 1-2. The results were as follows:. . Herbal substance Addition Deinococcal infestation. · ·, Ppm% ’Γ Betulin1 50 93 30 Pentahydroxyflavone 30 99.95

Trihydroxyflavone_100_84 '' dissolved in acetic acid

Of the herbal substances studied, pentahydroxyflavone was thus particularly effective in preventing the adhesion of deinococcal to steel.

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Comparative Example 1

For comparison, the ability of the antimicrobial agent Fennosa M9 (active ingredient methylene bistocyanate) to inhibit the adhesion of deinococcal to the steel surface was investigated. The study was carried out in the same manner as in Examples 1-2 above. The results were as follows:

Fennosan M9 Deinococcal adhesion inhibition ppm% 20 70 60 99 10 100 99 According to these results, Fennosan M9 was required at 60-100 ppm to effectively prevent deinococcal adhesion to steel surfaces. From the results, it can be concluded that the best plant extracts can achieve at least as good inhibition of the adhesion of deinococcal 15 to steel as the one commonly used by papermaking machines, methylene bistocyanate.

Comparative Example 2

The effect of eucalyptus oil disclosed in U.S. Patent No. 6,267,897 B on the adhesion of a deinococcal bacterium to a paper machine blade was also studied. The study was conducted in the same manner as in Examples 1-2 above. The results were as follows: •, ': Eucalyptus oil content Deinococcal anti-infectivity; ppm% 100 0 250 37 * * 25 Based on these results, virtually no inhibitory effect was found on eucalyptus oil at 100 ppm or 250 ppm.

In practice, only about 90% power should be considered significant. From this it can be concluded that eucalyptus oil does not work against the actual adhesive bacteria of hot paper machines.

! With the use of the plant extracts and herbal substances of the invention, pape • »,; whereas it is possible for the craft industry to obtain clear advantages over existing antimicrobial agents; they may be non-toxic or less toxic to paper machine bacteria than the biocides containing the synthetic active ingredients at operating concentrations. It is believed that naturally occurring biochemically produced plant compounds are more easily and perhaps more rapidly degraded to non-naturally occurring compounds than chemical synthesized compounds which are generally foreign to nature. Raw materials for plant extracts are readily available during the growing season. In a way, plant extracts are the "proprietary" substances of paper machines, as some of them can be made from the same types of wood as paper and board itself, albeit with different wood parts and different methods.

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Claims (8)

115502 ίο A method for preventing or removing the accumulation of Deinococcus geothermalis on the surfaces of paper or board machines by the thermophilic adhesive bacterium, characterized in that at least one of the following, plant parts: hardwood, coniferous bark, decayed coniferous or sparrow plant, or at least one herbal substance which is betulin or flavonol such as pentahydroxiflavone or trihydroxyflavone, or a mixture of said plant extract and said herbal substance. Method according to Claim 1, characterized in that the plant extract is derived from one of the following plants or parts of plants: rowan, birch, maple, willow, lingonberry, blueberry, pine bark or deciduous spruce branches. Process according to claim 1 or 2, characterized in that said plant extract is obtained by extraction of the plant or plant part with ethanol or acetone or a mixture thereof. A process according to any one of the preceding claims, characterized in that the plant extract or herbal substance or mixture thereof is added to the circulation water of paper or board machines at a product concentration of 1-1000 ppm, preferably 10-500 ppm, based on dry weight of plant extract or herbal substance. A method according to any one of the preceding claims, characterized in that the plant extract or herbal substance or mixture thereof is dosed into the circulation water of paper or board machines either periodically 2-8 times a day or in a single dose daily. Method according to one of the preceding claims, characterized in that the plant extract or herbal substance or mixture thereof is administered in a single dose; in doses of 500-5000 ppm, calculated on the dry matter of the plant extract or herbal substance:. the weight of the container to remove the germs on its surfaces, so-called. with a dose of shock. '30 7. A plant extract derived from any of the following plants or parts of plants: "hardwood, coniferous bark, decayed conifer or sparrow plant, or a herbal substance consisting of petulin or flavonol, such as pentahydroxyflavon or trihydroxy flavon, or said plant extract and said plant extract. the use of a mixture of substance to prevent or remove the buildup of the thermophilic adhesive bacterium Deinococcus geothermalis on paper or board machines, or to remove such deposits from said surfaces. Use according to claim 7, characterized in that said plant extract or said herbal substance or mixture thereof is added to the circulation water of paper or board machines at a product concentration of 1-1000 ppm, preferably 10-500 ppm, based on the dry weight of the plant extract or herbal substance.