WO2011023659A1

WO2011023659A1 - Kit and agent for preventing and/or controlling biological foaming

Info

Publication number: WO2011023659A1
Application number: PCT/EP2010/062257
Authority: WO
Inventors: Anne-Sophie Lepeuple; Gilberte Gaval; Cécile Persillon
Original assignee: Veolia Water Solutions & Technologies Support
Priority date: 2009-08-28
Filing date: 2010-08-23
Publication date: 2011-03-03
Also published as: FR2949460A1; FR2949459A1; WO2011023660A1; FR2949459B1

Abstract

The invention relates to a lysis agent of at least one strain of weblike bacteria, characterised in that it comprises at least one polypeptide selected from the following polypeptides: e) polypetide having an amino acid sequence that is one of the sequences SEQ ID N°9 or SEQ ID N°11; f) polypeptide having a lytic activity and an amino acid sequence that is at least 80% identical to one of the sequences SEQ ID N°9 ou SEQ ID N°11; g) polypeptide having a lytic activity and an amino acid sequence that is that of a fragment of one of the sequences SEQ ID N°9 ou SEQ ID N°11; and h) polypeptide comprising at least one polypeptide as defined in e), f) or g).

Description

KIT AND AGENT FOR PREVENTING AND / OR FIGHTING

AGAINST BIOLOGICAL FOAMING

The present invention relates to the field of water treatment. In particular, the present invention relates to agents for preventing and / or combating filamentous bacteria and to their use, in particular for the prevention and / or the fight against biological foaming involving filamentous bacteria.

The filamentous bacteria are likely to develop in water treatment plants implementing different types of processes including in particular biofilters, submerged membranes and especially activated sludge. These bacteria are associated with certain malfunctions of these water treatment plants, which manifest themselves mainly in two forms: swelling and organic foaming.

The swelling induces a bad decantation of the activated sludge following an increase of the volume occupied by these.

Organic foaming is characterized by the formation of a thick layer of organic foam on the surface of the structures. The main bacteria present in organic foams belong to the genera Microthrix, Nocardia and Gordonia. In particular, Nocardia amarae has been identified as the major bacterial species responsible for biological foaming (Pagilla et al., 2002, Water Science and Technology, Vol 46, p519-524, Iwahori et al., 2001, J. Bioscience Bioengineering, pp 77-79).

In addition, these phenomena of expansion and biological foaming are most often accompanied by start-ups of suspended solids in the treated water which, in addition to the operational problems on the water treatment plants, may lead to a deterioration of the quality. treated water and thus to greater or lesser exceedances of discharge standards.

The development of technical solutions to control the development of filamentous bacteria is therefore a major challenge to ensure the proper functioning of water treatment facilities and in particular water purification facilities. The means of fight against the filamentous bacteria currently available to the operators of water treatment plants essentially involve the use of chemical oxidants (such as chlorine and its derivatives, hydrogen peroxide, peracetic acid), the use of flocculating compounds (such as metal salts, iron chloride, talc, calcium carbonates) or the use of mechanical means (such as cavitation).

However, these different means are not specific to filamentous bacteria and have very variable efficiencies depending on the type of dysfunction encountered. In addition, these means are not always without consequences on the quality of the treated water and in particular on the activity of the purifying biomass during biological treatments. In addition, some of these means have the disadvantage of using products that do not respect the environment and / or whose implementation can be expensive in energy. The use of these agents, especially chemical agents, can also be restrictive. Indeed, some of these agents having particularly undesirable side effects (for example being toxic towards beneficial microorganisms), their use (dose, injection point, duration) requires a rigorous and constant control. Finally, the development of processes using these agents can be long, expensive and difficult to adapt to different situations of malfunctions encountered in water treatment plants.

There is therefore a need for agents that make it possible to fight effectively and specifically against the filamentous bacteria present in the waters to be treated, in particular wastewater and activated sludge, while preserving the quality of water treatment, in particular the treatment of water. sanitation of wastewater, as well as beneficial microorganisms, possibly ensuring the treatment of said water, and while being easy to use.

The inventors have now discovered the effectiveness of biological agents to solve all or part of the problems mentioned above. These agents are enzymes having the capacity to lyse at least one strain of filamentous bacteria present both in bacterial cultures and in water to be treated, in particular wastewater, than in activated sludge or in organic foams. Indeed, the inventors have surprisingly shown that these enzymes retain their enzymatic activity in such destabilizing environments as biological foams, activated sludge and water to be treated. In addition, the inventors have shown that, unexpectedly, these enzymes have the capacity to lyse not only the strain of filamentous bacteria from which they originate (either from the bacterial genome of said strain, or from the genome of a bacteriophage infecting said strain), but also from other strains involved in the biological foaming, in particular strains belonging to the species Gordonia amarae. However, it has been shown that Gordonia amarae is the major bacterial species responsible for biological foaming (Pagilla et al., 2002, Water Science and Technology, Vol 46, p519-524, Iwahori et al., 2001, J. Bioscience Bioengineering, pp 77-79).

Thus according to a first aspect, the subject of the invention is a first type of lysing agent for at least one strain of filamentous bacteria comprising:

at least one first type of polypeptide according to the invention chosen from the following polypeptides:

a) a polypeptide whose amino acid sequence is one of the sequences SEQ ID No. 5 or SEQ ID No. 7;

b) a polypeptide having a lytic activity and whose amino acid sequence has at least 80% identity with one of the sequences SEQ ID NO: 5, or SEQ ID NO: 7; c) a polypeptide having a lytic activity and whose amino acid sequence is that of a fragment of one of the sequences SEQ ID NO: 5, or SEQ ID NO: 7;

d) a polypeptide comprising at least one polypeptide as defined in a), b) or c);

and / or at least one first type of polynucleotide according to the invention, the nucleic acid sequence of which is one of the sequences SEQ ID No. 6 or SEQ ID No. 8.

The sequence SEQ ID No. 5 corresponds to a sequence identified hitherto as that of a putative lytic enzyme of the GTE5 phage of Gordonia terrae, hereinafter designated Gter.

The sequence SEQ ID No. 7 corresponds to the sequence SEQ ID No. 5 in which was inserted after the first methionine residue, the following amino acid sequence "HHHHHHIEGR" corresponding to a polyhistidine label ("6x-HisTAG") followed of a proteolytic cleavage site for factor Xa, to facilitate the purification of the protein.

Advantageously, said first type of polypeptide according to the invention consists of the sequence SEQ ID No. 5 or the sequence SEQ ID No. 7, in particular of the sequence SEQ ID

# 5. The sequence SEQ ID No. 6 corresponds to a nucleic acid sequence encoding the enzyme of sequence SEQ ID No. 5.

The sequence SEQ ID No. 8 corresponds to a nucleic acid sequence encoding the enzyme of sequence SEQ ID No. 7.

The subject of the invention is also a second type of lysing agent of at least one strain of filamentous bacteria comprising:

at least one second type of polypeptide according to the invention chosen from the following polypeptides:

e) a polypeptide whose amino acid sequence is one of SEQ ID NO: 9 or SEQ ID NO ^: 1;

f) a polypeptide having a lytic activity and whose amino acid sequence has at least 80% identity with one of the sequences SEQ ID No. 9 or SEQ ID No. 11; g) a polypeptide having a lytic activity and whose amino acid sequence is that of a fragment of one of the sequences SEQ ID No. 9 or SEQ ID No. 11;

h) a polypeptide comprising at least one polypeptide as defined in e), f) or g);

and / or at least one second type of polynucleotide according to the invention, the nucleic acid sequence of which is one of the sequences SEQ ID NO ^: 10 or SEQ ID No. 12.

The sequence SEQ ID No. 9 corresponds to a sequence identified hitherto as that of a putative N-acetyl muramoyl-L-alanine amidase of Nocardia farcinica, hereinafter referred to as NFar.

The sequence SEQ ID NO ^: 1 corresponds to the sequence SEQ ID No. 9 in which was inserted after the first methionine residue, the following amino acid sequence "HHHHHHIEGR" corresponding to a polyhistidine label ("6x-HisTAG") followed by a proteolytic cleavage site for factor Xa, to facilitate purification of the protein.

Advantageously, said second type of polypeptide according to the invention consists of the sequence SEQ ID No. 9 or the sequence SEQ ID No. 11, in particular of the sequence SEQ ID No. 9.

The sequence SEQ ID N ⁰ IO corresponds to a nucleic acid sequence encoding the enzyme of SEQ ID NO: 9. The sequence SEQ ID No. 12 corresponds to a nucleic acid sequence encoding the enzyme of sequence SEQ ID No. 11.

The first type of lysing agent according to the invention may further comprise at least one second type of polypeptide according to the invention and / or at least one second type of polynucleotide according to the invention.

Advantageously, in the first and second types of lysing agents according to the invention, the first and second types of polynucleotides according to the invention are included in an expression vector. The expression vectors that can be used can be in any form that is appropriate for the intended application.

The inventors have now shown that the Gter and Nfar enzymes in which a label has been inserted or not ("HHHHHHIEGR") have a lytic activity and in particular have the capacity to lyse at least one strain of filamentous bacteria, in particular involved in foaming. organic.

Such enzymes are therefore particularly advantageous for lysing at least one strain of filamentous bacteria, in particular involved in the biological foaming.

Thus, the subject of the invention is also the non-therapeutic use of at least a first or second type of polypeptide according to the invention and / or of at least a first or second type of polynucleotide according to the invention, for lysing at least one strain of filamentous bacteria, in particular a strain of filamentous bacteria involved in the biological foaming.

These lytic enzymes (lysines) Gter and Nfar, in which has been inserted or not a label ("HHHHHHIEGR"), can also be used in compositions for the prophylactic and therapeutic treatment of infections caused by filamentous bacteria and in particular bacteria of the genus Nocardia or Gordonia. In fact, the bacteria of the Nocardia and Gordonia families are opportunistic pathogens responsible for pulmonary infections and can lead to systemic infections or secondary localizations. They are also responsible for subcutaneous nocardiosis that can occur immediately in healthy subjects and succeeds to bites or injuries. Thus, these lytic enzymes may be alternatives to conventional antibiotics. They may have applications for cleaning wounds or be used in prevention when applied to dressings. These lytic enzymes can also be used for cleaning medical equipment and especially catheters to avoid infections. Finally, these lytic enzymes Gter and Nfar may have applications in dental hygiene for the treatment and prevention of peritoneal diseases, caries and dental plaque due to certain bacteria including Actinomyces and Nocardia.

According to another aspect, the subject of the invention is also an agent for preventing and / or combating biological foaming involving at least one strain of filamentous bacteria comprising:

at least one enzyme capable of lysing at least one strain of filamentous bacteria involved in the biological foaming; and or

at least one organism expressing said enzyme; and or

at least one bacterial lysate comprising said enzyme.

The said agents for preventing and / or combating biological foaming according to the invention have the following advantages in particular:

- They are effective and specific to at least one strain of filamentous bacteria and thus preserve other microorganisms that may provide water treatment;

- They have no negative impact on the quality of treated water;

- They are respectful of the environment;

- Their implementation is simple, fast and inexpensive in energy.

The term "biological foaming" in the sense of the present invention, the formation of biological foam associated with the proliferation of at least one strain of filamentous bacteria.

For the purposes of the present invention, the term "biological foam" means the foam formed, bound to the proliferation of at least one strain of filamentous bacteria.

For the purposes of the present invention, the term "bacterial lysate" is intended to mean the product of bacterial cell lysis. It is possible to obtain a bacterial lysate according to any technique well known to those skilled in the art, such as, for example, by sonication, French press, or else by using lysis buffers (such as: 10 μm KCl, 25 μm Hepes pH 7.6, 0.1mM EDTA, 12.5mM MgCl2, 10% glycerol, 0.1% Nonidet P40, 0.5mg / mL lysozyme).

Said enzymes capable of lysing at least one strain of filamentous bacteria may be lytic enzymes, in particular autolytic enzymes, also called lysines and autolysins respectively. The genes encoding said enzymes may be derived from genomes of bacteriophages or microorganisms, in particular from bacterial genomes. In particular, said enzymes have the capacity to lyse not only the strain of filamentous bacteria from which they originate (either from the bacterial genome of said strain or from the genome of a bacteriophage infecting said strain), but also from other strains involved in organic foaming, including strains belonging to the same bacterial order and in particular strains belonging to the species Nocardia amarae.

Said enzymes according to the invention, capable of lysing at least one strain of filamentous bacteria can be identified by methods comprising:

the selection of putative or already described enzymes capable of lysing at least one strain of filamentous bacteria, by in silico and / or bibliographical studies followed by tests of the desired enzymatic activity, from the putative or described enzymes thus selected.

Said enzymes according to the invention capable of lysing at least one strain of filamentous bacteria can also be identified on the basis of genomic libraries constructed from samples of bacterial cultures or samples of water to be treated, in particular water or activated sludge, or organic foams, having at least one strain of filamentous bacteria. According to this second approach, it is possible from samples of bacterial cultures or samples of water to be treated, in particular wastewater or activated sludge, or even biological foams, after induction or not of a lyrical cycle. bacteriophage (for example by mitomycin):

on the one hand, to construct a metagenomic library and to screen it for the desired enzymatic activity; and

on the other hand to isolate bacteriophages from lysis plaques, to construct genomic libraries of the phages thus isolated and to screen them for the desired enzymatic activity.

The desired enzymatic activity, namely the ability to lyse at least one strain of filamentous bacteria can be determined by tests well known to those skilled in the art. By way of example, mention may be made of the use of a spectrophotometer by measuring the optical density (at 600 nm with a dilution of a bacterial suspension), or the microscopic observation associated with colorations of the structure, morphology of the filaments or the use of bacterial viability kits such as the kit "LIVE / DEAD® Bacterial Viability Kit" (BacLight ™) from Molecular Probes.

Enzymatic tests can be carried out on samples of bacterial cultures or on samples of water to be treated, in particular waste water or sludge activated, or biological foams capable of comprising at least one strain of target filamentous bacteria.

The present invention encompasses the enzymes according to the invention which are native, synthetic, semisynthetic, recombinant and their analogues.

In particular, said enzyme according to the invention may be in the form of a fusion protein (chimeric protein) comprising at least one enzymatic domain having the capacity to lyse at least one strain of filamentous bacteria, said domain being linked in a manner operable to at least one other polypeptide.

Said other polypeptide may for example be a "tag" allowing the labeling of the fusion protein. This tag may allow detection, purification of the fusion protein and / or immobilization of the fusion protein on a support. Examples of such labels include those well known to those skilled in the art such as GST, His-Tag, Tag-V5. The fusion protein comprising a His-Tag tag can thus be advantageously immobilized and / or purified on a support comprising divalent cations (nickel, cobalt, copper).

Said other polypeptide may also comprise a substrate binding domain, thus promoting the immobilization of the fusion protein on a support comprising said substrate. Thus said second polypeptide may comprise a maltose binding domain (Maltose Binding Protein) which will allow the fusion protein to be advantageously immobilized on a support having maltose molecules.

Moreover, said other polypeptide may comprise, for example, at least one enzymatic domain having the capacity to lyse at least one strain of filamentous bacteria. Thus, advantageously, said enzyme according to the invention can be in the form of a fusion protein (chimeric protein) comprising several active sites, several enzyme domains having the ability to lyse different strains of filamentous bacteria.

In particular, said at least one enzyme according to the invention may comprise a polypeptide chosen from the following polypeptides:

said first type of polypeptide according to the invention as defined above;

said second type of polypeptide according to the invention as defined above;

a third type of polypeptide according to the invention, said third type of polypeptide being chosen from the following polypeptides: i) a polypeptide whose amino acid sequence is one of the SEQ ID sequences

No. 1 or SEQ ID No. 3;

j) a polypeptide having a lytic activity and whose amino acid sequence has at least 80%, preferably at least 85%, even more preferably at least 90% and most preferably at least 95% identity with one of the sequences SEQ ID No. 1 or SEQ ID No. 3;

k) a polypeptide having a lytic activity and whose amino acid sequence is that of a fragment of one of the sequences SEQ ID No. 1 or SEQ ID No. 3;

1) a polypeptide comprising at least one polypeptide as defined in i), j) or k).

Advantageously, said third type of polypeptide according to the invention consists of the sequence SEQ ID No. 1 or of the sequence SEQ ID No. 3, in particular of the sequence SEQ ID No. ¹ .

The sequence SEQ ID No. 1 corresponds to the sequence of a lysine of the Actinomyces viscosus phage AV-I, hereinafter designated Av-I.

The sequence SEQ ID No. 3 corresponds to the sequence SEQ ID No. 1 in which was inserted after the first methionine residue, the following amino acid sequence "HHHHHHIEGR" corresponding to a polyhistidine label ("6x-HisTAG") followed of a proteolytic cleavage site for factor Xa, to facilitate purification of the protein.

Surprisingly, the inventors have demonstrated that the three enzymes Av-I, Gter and Nfar, in which a label ("HHHHHIEGR") has been inserted, have the capacity to lyse the strain of filamentous bacteria of which they are exfoliates (either from the bacterial genome of said strain or from the genome of the bacteriophage infecting said strain), but also from other strains involved in the biological foaming, in particular strains of filamentous bacteria belonging to the families Nocardiaceae, Gordoniaceae and the genus Microthrix and especially strains belonging to the species Nocardia amarae. In addition, the inventors have shown that, unexpectedly, these enzymes retain their activity in environments as destabilizing as water to be treated, in particular wastewater, activated sludge, or organic foams.

The fragments of the sequences SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, SEQ ID NO: 7, SEQ ID NO: 9, SEQ ID NO ^: 1 have minimum sizes allowing the activity to be retained. lytic and in particular to retain the ability to lyse at least one strain of filamentous bacteria, preferably involved in the biological foaming.

In particular, said enzyme according to the invention comprises one of the enzymatic domains of the sequences SEQ ID No. 1, SEQ ID No. 5 and SEQ ID No. 9 which have the capacity to lyse at least one strain of filamentous bacteria.

In particular, said enzyme according to the invention may be a fusion protein comprising at least one of the enzymatic domains of the sequences SEQ ID No. 1, SEQ ID No. 5 and SEQ ID No. 9 which have the capacity to lyse at least one strain of filamentous bacteria.

Advantageously, said agent for preventing and / or combating biological foaming according to the invention may comprise at least one enzyme capable of lysing at least one strain of filamentous bacteria involved in the biological foaming; said at least one enzyme comprising a polypeptide selected from the following polypeptides:

said first type of polypeptide according to the invention as defined above;

said second type of polypeptide according to the invention as defined above;

said third type of polypeptide according to the invention as defined above.

Advantageously, said agent for preventing and / or combating biological foaming according to the invention may comprise:

i) - at least one first enzyme capable of lysing at least one strain of filamentous bacteria involved in the biological foaming; and or

at least one organism expressing said first enzyme; and or

at least one bacterial lysate comprising said first enzyme;

said at least one first enzyme comprising a first type of polypeptide according to the invention as defined above; and

ii) - at least one second enzyme capable of lysing at least one strain of filamentous bacteria involved in the biological foaming; and or

at least one organism expressing said second enzyme; and or

at least one bacterial lysate comprising said second enzyme; said at least one second enzyme comprising a second type of polypeptide according to the invention as defined above; and

iii) - at least one third enzyme capable of lysing at least one strain of filamentous bacteria involved in the biological foaming; and or

at least one organism expressing said third enzyme; and or

at least one bacterial lysate comprising said third enzyme;

said at least one third enzyme comprising a third type of polypeptide according to the invention as defined above.

i) - at least one first enzyme capable of lysing at least one strain of filamentous bacteria involved in the biological foaming;

ii) - at least one second enzyme capable of lysing at least one strain of filamentous bacteria involved in the biological foaming;

said at least one second enzyme comprising a second type of polypeptide according to the invention as defined above; and

iii) - at least one third enzyme capable of lysing at least one strain of filamentous bacteria involved in the biological foaming;

The use of these first, second and third types of polypeptides according to the invention in the said agent for preventing and / or preventing biological foaming according to the invention has the advantage of obtaining a broad spectrum of activity. against strains of filamentous bacteria.

Said organism expressing the enzyme according to the invention may be a unicellular or multicellular microorganism.

In particular, said organism expressing the enzyme may be chosen from bacteria and fungi. In particular, said organism expressing the enzyme is a microorganism capable of degrading at least partially the organic substances present in the water to be treated; the use of such a microorganism optimizes water treatment. Said waters to be treated include, in particular:

- Wastewater ;

- wastewater at all stages of treatment and at the post-treatment stage;

- water intended to be treated for the purpose of purification, such as surface water, karstic waters, groundwater, seawater;

- water at all stages of potabilisation and the post-potabilisation stage.

For the purposes of the present invention, the term "filamentous bacterium" means any bacterium capable of forming a bacterial filament. A bacterial filament is a colony of cells that, after cell division, do not separate. This colony grows along a single or branched axis, forming a filament. The identification of filamentous bacteria is based on morphological criteria most often associated with staining (Eikelboom, 1975) and / or on phylogenetic sequence homologies (based, for example, on the homology of 16S DNA sequences).

In particular, said strain of filamentous bacteria may be included in the group comprising bacterial strains of the order Actinomycetales.

In particular, said strain of filamentous bacteria may be included in the group comprising:

- bacterial strains of the family Nocardiaceae;

- strains of bacteria of the family Gordoniaceae;

strains of bacteria of the family including genus Microthrix;

- strains of bacteria of the family including the type of Eikelboom 0675;

- strains of bacteria of the family including the type of Eikelboom 0581.

strains of bacteria of the genus Nocardia;

- strains of bacteria of the genus Gordonia,

strains of bacteria of the genus Microthrix;

strains of bacteria of the genus including the type of Eikelboom 0675;

strains of bacteria of the genus including the type of Eikelboom 0581. More particularly, said strain of filamentous bacteria may be included in the group comprising:

strains of bacteria of the species Nocardia farcinica, Nocardia forms;

- strains of bacteria of the species Gordonia terrae, Gordonia amarae;

strains of bacteria of the species Microthrix parvicella;

strains of bacteria of the type of Eikelboom 0675;

strains of bacteria of the type of Eikelboom 0581.

In said agent for preventing and / or combating biological foaming according to the invention, said at least one enzyme and / or said at least one organism expressing the enzyme according to the invention can be immobilized on a support.

The use of a support has the particular advantages of protecting the enzymes from biodegradation by proteases or microorganisms that may be present in the water. The use of a support is therefore particularly advantageous in the case of biological treatment of water such as activated sludge processes using microorganisms. In addition, immobilization on a support makes it possible to limit the denaturation and / or the inactivation of the enzyme, which may be due to pH variations, high temperatures, denaturants, heavy metals, fatty acids or salts of biles. The use of a support may also have the advantage of allowing the recovery of the enzyme, the expression system according to the invention after use.

The stability on the support of the enzyme and / or of the organism expressing said enzyme according to the invention can be further improved by modifying its microenvironment, which can be achieved:

by blocking the chemical groups remaining free on the support after immobilization of the enzyme or of the expression system;

by grafting hydrophilic macromolecules near the enzyme or the expression system;

by immobilizing the enzyme on the support via a spacer.

Thus, immobilization of the enzyme on the support can be direct or indirect via a spacer (linker). Examples of usable spacers include aldehyde dextran, PEG diamine, amino dextran, albumin and 6 amino-caproic acid. The immobilization of the enzyme or of the expression system of said enzyme on the support can be carried out according to any technique well known to those skilled in the art such as by covalent bonding, by adsorption, by grafting, by cross-linking Covalent with polyfunctional reagents or a ligand-receptor system.

Immobilization by adsorption has the advantage of being a simple and inexpensive process, but relies on weak bonds. However, desorption problems can be avoided by cross-linking, eg glutaraldehyde, after adsorption (Greenberg and Mahoney, 1981, Proc Biochem., Feb / March: 2-8).

Covalent immobilization has the advantage, when it involves functional groups located away from the active site of the enzyme, to obtain a better specific activity and a better yield than during immobilization by adsorption. In addition, there are methods for selecting the groups involved in the binding to the support (Cano et al., 2006, J. Membrane Sci., 280 (1-2): 383-388). In addition, this technique allows the use of spacers (linkers) to create a hydrophilic microenvironment and thus optimize stability and enzymatic activity.

Immobilization by a "ligand-receptor" system relies on the affinity of a receptor for a ligand placed on the support. This technique can also allow the purification of the enzyme. As examples, it is possible to use the "streptavidin-biotin" system, in which the enzyme is biotinylated in vitro and the streptavidin is grafted onto the support. Mention may also be made of the maltose and His-Tag systems described above. This "ligand-receptor" system makes it possible to improve the enzymatic activity and to increase the lifetime of the enzyme compared with adsorption or covalent immobilization techniques.

Said support according to the invention may have at least one of the following characteristics:

a density lower than that of said waters and, if appropriate, that of activated sludge, in particular a density of less than 1;

pores having a diameter at least equal to the diameter of the filamentous bacteria, in particular at least 10 μm, more particularly at least 20 μm and especially at least 50 μm;

- not biodegradable, in particular not degradable by the micro-organisms present in said waters; - insoluble in water;

a sufficient mechanical strength to allow easy handling;

- sufficient size to allow recovery after use;

geometric properties leading to an available surface greater than 1500 m ² / m ³ .

In particular, said support can be adapted to allow its use on the surface of the water treatment basins, where are located the biological foams involving at least one strain of filamentous bacteria.

In particular, said support may comprise at least one material chosen from the group comprising: sintered clay, in particular expanded sintered clay, polystyrene, in particular expanded polystyrene, polyurethane, alumina, glass, nylon, polyester, rock wool, silicate, cork, ceramic, polysulfone, copolymers of vinyl alcohol and vinyl-butyral, polyamine polymers, polyazetidine, polyphenylalanine-lysine, polyether-olefinic.

Some materials may be used for direct immobilization. In this case, said support may comprise at least one material chosen from the group comprising expanded sintered clay, expanded polystyrene, polyurethane, alumina, glass, nylon, polyester, rockwool, silicate , cork, ceramic, polysulfone, copolymers of vinyl alcohol and vinyl-butyral, preferably expanded sintered clay, expanded polystyrene, polyurethane, alumina, glass, nylon and cork.

Other materials may be used for indirect immobilization. In this case, said support may comprise a first material covered with a second material comprising polymers. Thus, the enzyme or the expression system according to the invention may be immobilized on at least one polymer chosen from the group comprising polyamine (especially polyethyleneimine), polyazetidine, polyphenylalanine-lysine, polyether-olefinic and polysulfone polymers. said at least one polymer being deposited on at least one material selected from the group consisting of polystyrene, alumina, glass, nylon, polyester.

Said support may be in any form adapted to the intended application. In particular, said support may be a solid support in spherical form such as a ball, a bale, a granule, preferably greater than 5 mm in size and with a density of less than 1, or in the form of a tarpaulin such as a membrane, a fiber, a fabric. According to a particular embodiment of said agent for preventing and / or combating biological foaming according to the invention, said at least one enzyme and / or said at least one organism expressing the enzyme and / or said at least one bacterial lysate according to the invention can be lyophilized.

Indeed, the inventors have shown that the three enzymes Av-I, Gter and Nfar in which has been inserted or not a label ("HHHHHHIEGR"), retain their lytic activity even when they have been lyophilized.

The lyophilized form has the advantages of stabilizing the enzyme and reducing the volumes of enzyme and / or said organism expressing the enzyme and / or said bacterial lysate to be used.

According to another aspect, the subject of the invention is a kit for preventing and / or combating biological foaming involving at least one strain of filamentous bacteria comprising:

at least one agent for preventing and / or combating biological foaming involving at least one strain of filamentous bacteria according to the invention, said agent being defined above; and

at least one support capable of immobilizing said agent.

Said support can be any support as defined above.

The present invention also relates to the use of at least one enzyme according to the invention capable of lysing at least one strain of filamentous bacteria involved in the biological foaming; and or

at least one organism expressing said enzyme; and or

at least one bacterial lysate comprising said enzyme;

as an agent for preventing and / or combating biological foaming involving at least one strain of filamentous bacteria.

Said at least one enzyme according to the invention is as defined above. In particular, said at least one enzyme may comprise a polypeptide chosen from the following polypeptides:

said first type of polypeptide according to the invention as defined above;

said second type of polypeptide according to the invention as defined above; said third type of polypeptide according to the invention as defined above.

The invention also relates to a water treatment method including a step of preventing and / or fighting against the biological foaming of said water, said biological foaming involving at least one strain of filamentous bacteria, said step comprising contacting said waters with at least one agent for preventing and / or controlling at least one strain of filamentous bacteria according to the invention; said agent according to the invention being as defined above.

Said waters in the water treatment processes according to the invention include in particular:

- Wastewater ;

- wastewater at all stages of treatment and at the post-treatment stage;

- water at all stages of potabilisation and the post-potabilisation stage.

Thus, in the water treatment methods according to the invention, said agent for preventing and / or controlling at least one strain of filamentous bacteria may be brought into contact with the waters to be treated, in particular the wastewater, the activated sludge or organic foams.

Said water treatment methods according to the invention may be varied and include, without limitation, bio filters, bacterial beds, sequenced feed tanks, submerged membranes, natural lagooning or activated sludge.

In particular, said water treatment methods according to the invention implement activated sludge.

In particular, in the water treatment methods according to the invention, said enzyme, said organism expressing said enzyme, said bacterial lysate are as defined above and may be in any form suitable for the intended application. Advantageously, said enzyme, said organism expressing said enzyme or said bacterial lysate comprising said enzyme are in freeze-dried form; putting them in contact with said waters for hydration. Lyophilization has the advantages of stabilizing the enzyme and reducing the volumes of enzymes, said body expressing said enzyme and said bacterial lysate according to the invention for use in the water treatment methods according to the invention. Advantageously, the processes according to the invention can implement at least one of the domains, preferably all of the enzymatic domains of the sequences SEQ ID No. 1, SEQ ID No. 5 and SEQ ID No. 9, which have the ability to lyse at least one strain of filamentous bacteria.

The implementation of all of said enzymatic domains of the sequences SEQ ID No. 1, SEQ ID No. 5 and SEQ ID No. 9 has the advantage of obtaining a broad spectrum of activity vis-à-vis strains of filamentous bacteria.

According to a particular embodiment of the water treatment methods according to the invention, said agent is immobilized on a support. Said support can be defined as above. The immobilization methods that can be used can be those defined above. The advantages of using a carrier in the water treatment processes according to the invention are as described above.

Said water treatment methods according to the invention may further comprise the following step:

separating said enzyme from said organism expressing the enzyme and / or said bacterial lysate and said waters.

Such separation can be performed by any technique well known to those skilled in the art such as for example by immunoprecipitation.

When said enzyme and / or said organism expressing the enzyme is immobilized on a support, said water treatment methods according to the invention may further comprise the following step:

the separation of said support and said waters.

In another aspect, the enzyme, said organism expressing said enzyme and said bacterial lysate comprising said enzyme according to the invention may be useful for detecting at least one strain of filamentous bacteria in water samples.

Thus, according to a particular embodiment, the water treatment methods according to the invention may comprise a step of detecting at least one strain of filamentous bacteria, said step comprising the following phases:

contacting a sample of said waters capable of comprising at least one strain of filamentous bacteria with said at least one agent for preventing and / or controlling at least one strain of filamentous bacteria according to the invention; and detection of the lysed bacteria and / or detection of the lysis of the bacteria with at least one appropriate detection system.

This step of detecting at least one strain of filamentous bacteria can be advantageously implemented before the step of controlling the biological foaming in the water treatment methods according to the invention. Thus, the anti-foaming agents according to the invention may be chosen to specifically target at least said strain of filamentous bacteria thus detected. This step then makes it possible to optimize the fight against organic foaming.

As an example of a detection system suitable for the detection of lysed bacteria, mention may be made of fluorescent DNA markers such as Syto 9 (marker of intact and lysed bacteria) and propidium iodide (lysed bacteria marker). ) or the EMA-PCR technique as described in the article by Rudi K et al. (2005) (Rudi K, Moen B, Dromtorp SM, Holck AL.) Use of Ethidium Monoazide and PCR in Combination for Quantification of Viable andDeduced Cells in Applied Appl. Environ Microbiol. 2005 Feb; 71 (2): 1018-24) .

As an example of a detection system suitable for detecting the lysis of bacteria, mention may be made of ATPmetry as described in the article by Schuch et al. (Schuch R, Nelson D, Fischetti VA.A bacteriolytic agent that detects and kills Bacillus anthracis, Nature, Aug. 2002; 418 (6900): 884-9).

The present invention also relates to a kit for detecting at least one strain of filamentous bacteria comprising:

an enzyme capable of lysing at least one strain of filamentous bacteria; and or

a system for expressing said enzyme; and or

a bacterial lysate comprising said enzyme; and

a system for detecting lysed bacteria and / or lysing bacteria.

In particular, in the detection kit according to the invention, said enzyme, said system for expressing said enzyme, said bacterial lysate are as defined above and may be in any form appropriate to the intended application. In particular, said enzyme, said expression system or said bacterial lysate comprising said enzyme are in freeze-dried form. According to a particular embodiment of said detection kit according to the invention, said agent is immobilized on a support. Said support and said immobilization methods that may be used may be as defined above. The present invention also relates to an in vitro diagnostic method, the presence of at least one strain of filamentous bacteria in a sample, comprising the following steps:

contacting a sample that may comprise at least one strain of filamentous bacteria with:

an enzyme capable of lysing at least one strain of filamentous bacteria according to the invention; and or

a system for expressing said enzyme; and or

a bacterial lysate comprising said enzyme;

detection of the lysed bacteria and / or lysis of the bacteria with at least one appropriate detection system.

Other advantages and features of the invention will become apparent from the following examples.

These examples are given for illustrative and not limiting.

FIG. 1 illustrates the lytic activity of the Gter, Av-I and Nfar enzymes and of the mixture of these three enzymes ("lysine mix") on the strain Gordonia amarae ATCC 27809 isolated from biological foams collected in the treatment station of water, before lyophilization of said enzymes.

FIG. 2 illustrates the lytic activity of the mixture of the three enzymes ("lysine mix") on the strain Gordonia amarae ATCC 27809 isolated from biological foams collected in a water treatment station, after lyophilization of the enzymes.

FIG. 3 represents the effect of the dose (100 μl, 200 μl and 300 μl) of the mixture of the three enzymes Gter, Av-I and Nfar ("mix lysines") on the inhibition of the growth of the pure Gordonia strain. ATCC 27809 mite isolated from biological moss collected in a water treatment plant.

FIG. 4 illustrates the absence of inhibition activity of the growth of the mixture ("lysine mix") of the three enzymes Gter, Av-I and Nfar, on the bacterium Escherichia coli.

FIG. 5 illustrates the absence of growth inhibition activity of the mixture ("lysine mix") of the three enzymes Gter, Av-I and Nfar on the bacterium Bacillus subtilis. FIG. 6 illustrates the growth inhibition activity of the mixture ("lysine mix") of the three Gter, Av-I and Nfar enzymes on the strain Gordonia amarae ATCC 27809 isolated from biological foams collected in a treatment plant. 'waters.

FIG. 7 represents the state of the membranes of the bacteria belonging to the strain Gordonia amarae ATCC 27809 in the absence of the mixture of the three enzymes Gter, Av-I and Nfar, "lysine mix".

FIG. 8 represents the state of the membranes of the bacteria belonging to the strain Gordonia amarae ATCC 27809 in the presence of the mixture of the three enzymes Gter, Av-I and Nfar, "lysine mix", for 30 minutes, 95 minutes or 1595 minutes.

FIG. 9 illustrates the lytic activity of the non-lyophilized Av-I enzyme on various diluted biological foams collected in a water treatment station and on the strain Gordonia amarae ATCC 27809 (control).

FIG. 10 illustrates the lytic activity of the non-lyophilized Gter enzyme on various diluted biological foams collected in a water treatment station and on the strain Gordonia amarae ATCC 27809 (control).

FIG. 11 illustrates the lytic activity of the non-lyophilized Nfar enzyme on various diluted biological foams collected in a water treatment station and on the strain Gordonia amarae ATCC 27809 (control).

FIG. 12 illustrates the lytic activity of the mixture of the three non-lyophilized Gter, Av-I and Nfar "lysine mix" enzymes on different diluted biological foams collected in a water treatment plant and on the strain Gordonia amarae ATCC 27809 (control) .

Figure 13 (A and B) shows the effect of mixing the three freeze-dried lyophilized Gter, Av-I and Nfar "mix lysine" enzymes on a sample of undiluted organic foams taken from a water treatment plant; FIG. 13A represents a sample of undiluted biological foams collected in a water treatment station in the absence of the "lysine mix", said sample being observed under a microscope after "Baclight"labeling; FIG. 13B represents a sample of undiluted biological foams collected in a water treatment station after 180 minutes of incubation with the "lysine mix", said sample being observed under a microscope after "Baclight" labeling. Examples

I. Example 1 Evaluation of the lytic activity of the enzymes Gter, Av-I, Nfar on pure strains of filamentous bacteria

The sequences of the Gter, Av-I and Nfar enzymes, namely the sequences SEQ ID No. 4, SEQ ID No. 8 and SEQ ID No. 12 (optimized for expression in Escherichia coli) were cloned and expressed in Escherichia coli to allow synthesis of the corresponding proteins.

The lytic activity of these three enzymes thus produced was tested on the following two types of target strains:

pure strains of filamentous bacteria whose three enzymes Gter, Nfar and Av-1 are normally specific, namely the species Gordonia terrae, Nocardia farcinica and Actinomyces viscosus. Indeed, the Gter enzyme has been identified in the genome of the GTE5 phage targeting Gordonia terrae, the Av-I enzyme has been identified in the genome of a specific phage of Actinomyces viscosus and the Nfar enzyme has been identified. identified in Nocardia farcinica; and

- pure strains of filamentous bacteria isolated from biological moss collected in a water treatment plant, namely the strains Gordonia amarae DSM 43392 and Gordonia amarae ATCC 27809. Indeed, Gordonia amarae has been identified as the predominant bacterial species in organic foams. In addition, it has been demonstrated that Gordonia amarae is the major bacterial species responsible for biological foaming (Pagilla et al., 2002, Water Science and Technology, Vol 46, p519-524, Iwahori et al., 2001, J. Bioscience Bioengineering, pp 77-79).

The lytic activity of these three enzymes was evaluated by determining the kinetics of lysis of the pure strains of filamentous bacteria by measuring the optical density at 600 nm (OD 600). A regular decrease over time of the optical density at 600 nm (ODβoo) reflects the efficiency of the enzymes to lyse target strains of filamentous bacteria.

This measurement is carried out with a UV-Visible spectrophotometer in 96-well microplates (200 μL wells). The conditions for carrying out the measurements are set out in Table 1.

TABLE 1 Composition of the reaction media for the evaluation of lysine activity

Optical density measurements at 600 nm are made in kinetics every minute on the control and test wells.

The results are expressed in Delta DO 600 = f (t), knowing that:

Delta DO at 600nm = OD test (with lysines) - control OD (without lysines, with BSA)

By removing the 600 nm (OD 600) optical density value of the negative control from that of the lysine assay, any interferences related to the sample are eliminated. In the case of a proven efficiency of lysines, the delta DO is supposed to be negative.

The lytic activity of the enzymes is thus determined by calculating in the presence of an enzyme ("enzyme") and in the absence of an enzyme ("control"), the difference of the optical density at 600 nm (ODβ00) at a time. given t (Do _t ) with respect to to (DO _to ), as follows:

(D 0 _r DO _to ) enzyme- (DO-DO _to ) control

The results of these tests are shown in Table 2 below:

Table 2: Lytic activity of the three enzymes on different pure strains of filamentous bacteria. (+) represents an important lytic activity; (+/-) represents a weak lytic activity; (-) represents the absence of lytic activity.

As shown in Table 2 above, the three enzymes Gter, Av-I and Nfar produced in E. coli exhibit lytic activity not only with respect to the filamentous bacteria of which they are normally specific, namely respectively Gordonia terrae , Actinomyces viscosus and Nocardia farcinica, but also with respect to pure filamentous bacteria isolated from biological moss collected in a water treatment plant, such as the strain Gordonia amarae ATCC 27809.

This experiment shows the effectiveness of each of the three enzymes Gter, Av-I and Nfar to inhibit the growth of filamentous bacteria involved in the biological foaming, including the strain Gordonia amarae ATCC 27809.

II. Example 2 Evaluation of the Effect of Lyophilization on the Activity of Lysines

The effect of lyophilization on the lytic activity of the three enzymes Gter, Av-I and Nfar was tested.

The lytic activity of the various enzymes Gter, Av-I and Nfar as well as a mixture of these three enzymes (called "lysine mix") was thus tested on the pure strain Gordonia amarae ATCC 27809 isolated from organic moss taken in water treatment station, before (Figure 1) and after (Figure 2) lyophilization of said enzymes.

The lytic activity of the enzymes was determined as indicated above in Example 1. The results are shown in Figures 1 and 2.

As shown in FIGS. 1 and 2, lyophilization of the lysines has no impact on the lytic activity of the various enzymes.

This experiment demonstrates that the lytic activity of the Gter, Av-I and Nfar enzymes has been preserved after lyophilization of these enzymes.

III. Example 3: Effect of the dose of the mixture of the three enzymes Gter, Av-I and Nfar ("mix lysines") on the strain Gordonia amarae ATCC 27809

Various doses (100, 200 and 300 μl) of the mixture ("lysine mix") of the three enzymes Gter, Av-I and Nfar were tested on the pure strain Gordonia amarae ATCC 27809 isolated from biological moss collected at the breeding station. water treatment. The growth inhibition efficiency was measured.

In the corresponding negative controls, the enzymes were replaced by BSA (Bovine Albumin Serum). The growth kinetics of the pure strain Gordonia amarae ATCC 27809 was determined by spectrophotometer measurement of the optical density at 600 nm (ODβO0) over 8 days.

The results are shown in Figure 3.

As shown in Figure 3, upon application of a 200 μl dose of the mixture ("lysine mix") of the three enzymes Gter, Av-I and Nfar, the growth of the filamentous bacterium Gordonia amarae ATCC 27809 is completely inhibited .

This experiment confirms the effectiveness of the enzymes Gter, Av-I and Nfar in inhibiting the growth of filamentous bacteria involved in the biological foaming.

IV. Example 4 Evaluation of the Specificity of the Mixtures ("Lysine Mix") of the Three Gter, Av-I and Nfar Enzymes

The lytic activity of the mixture ("lysine mix") of the three enzymes Gter, Av-I and Nfar was studied on microorganisms useful for purification, including two model microorganisms: Escherichia coli (gram negative bacterium) and Bacillus subtilis (Gram positive bacterium). The control experiment was carried out on the strain Gordonia amarae ATCC 27809.

Bacteria were incubated with lysine mix for 7 or 13 days.

In the corresponding negative controls, the enzymes were replaced by BSA (Bovine Albumin Serum).

The kinetics of growth of the different bacteria was determined by spectrophotometric measurement of the optical density at 600 nm (OD β 0) over 7 or 13 days.

The results are shown in Figures 4 to 6.

As shown in FIGS. 4 to 6, the addition of the "lysine mix" at the time of inoculation of the cultures of the different pure bacterial strains shows that if the "lysine mix" effectively inhibits the growth of the strain G. amarae 27809 itself after 7 days of incubation with said "lysine mix", it has no impact on the growth of bacteria Bacillus subtilis and E. coli even after 7 or 13 days of incubation.

These tests demonstrate that the action of lysines is specific to filamentous bacteria, in particular involved in the biological foaming. Enzymes Gter, Av-I and Nfar have the advantage of not having a detrimental effect on other microorganisms, especially on the biomass useful for water treatment.

V. Example 5: Evaluation of the mode of action of the mixture "lysine mix" of the three enzymes Gter, Av-I and Nfar

V. Inhibition of growth

As shown in Figure 6, the mixture ("lysine mix") of the three enzymes Gter, Av-I and Nfar has an inhibitory effect on the growth of the strain Gordonia amarae ATCC 27809 when added at the beginning of the bacterial growth even after 7 days of incubation.

V.2 Degradation of the filament membrane

The effect of mixing the three enzymes Gter, Av-I and Nfar ("lysine mix") on the integrity of the bacterial membranes belonging to the strain Gordonia amarae ATCC 27809 was studied using the kit "LIVE / DEAD ® Bacterial Viability Kit (BacLight ™) from Molecular Probes as recommended by the supplier, combined with microscopic observation and enumeration.

This kit "LIVE / DEAD® Bacterial Viability Kit" generates a differential marking which makes it possible to distinguish micro-organisms presenting membranes of integrity from those whose membranes are degraded.

100 μL of reaction medium (see Table 1 of Example 1) are diluted 1/10 in buffer. 3μL of Baclight labeling solution is added to this mixture and after 15min of incubation, 5μL are placed between slide and lamellae. The observation is carried out under an epifluorescence microscope at a magnification × 1000. For each sample, the cell counts are carried out over 20 microscopic fields then brought back to the initial volume of foams or of culture.

The counts were thus carried out on test and control tubes at TO, T + 30 min, T + 90 min and T + 26 h (1595 min).

Membranes of bacteria belonging to the strain Gordonia amarae ATCC 27809 were observed for 30 minutes (t30), 95 minutes (t95) and 1595 minutes (tl595) after addition. (Figure 8) or not (Figure 7) of the mixture of three enzymes Gter, Av-I and Nfar, "lysine mix" to bacteria.

The results are shown in Figures 7 and 8.

As shown in Figures 7 and 8, after 30 minutes of incubation with the "lysine mix", the proportion of bacteria with a degraded membrane (compared to the control without lysine) are very important. These results indicate that lysines Gter, Av-I and Nfar degrade the membrane of filamentous bacteria, in particular belonging to the strain Gordonia amarae ATCC 27809.

VI. EXAMPLE 6 Evaluation of the Efficacy of the Three Gter, Av-I and Nfar Enzymes and of the Mixture of these Three Lysine Mixing Enzymes on Different Biological Foam Samples taken from a Water Treatment Plant

VLl Tests carried out with diluted biological foams collected in a water treatment plant and non-freeze-dried lysines

The lytic activity of the three enzymes Gter, Av-I and Nfar and the mixture of these three enzymes "lysine mix", was tested on different samples of biological foams collected in the water treatment plant. All of these different biological foam samples include bacteria belonging to the genus Nocardia and Gordonia at varying concentrations. Some of these biological foam samples further include bacteria belonging to the genus Microthrix.

The relative presence of bacteria belonging to the genera Nocardia, Gordonia and Microthrix in these different biological foam samples is shown in Table 3 below:

Table 3: Relative presence of bacteria belonging to the genus Nocardia, Gordonia and Microthrix in the different samples of biological foams tested. (-) absence of bacteria; (+) weak presence of bacteria; (+++) important presence of bacteria. The tests were carried out in parallel with as positive control the bacteria belonging to the pure strain Gordonia amarae ATCC 27809.

The biological foam samples (1 to 4) were diluted 1/100 and incubated with 100 μl of Gter, Av-I or Nfar enzymes or a mixture of these three enzymes "lysine mix" for 90 minutes.

The kinetics of lysis of the bacteria present in the biological foam samples or that of the bacteria belonging to the pure strain Gordonia amarae ATCC 27809 was determined by spectrophotometric measurement of the optical density at 600 nm (OD 600) over 90 minutes. This measurement was carried out with a UV-visible spectrophotometer in disposable tanks whose optical path is 10 mm. The conditions for carrying out the measurements are shown in Table 4.

Table 4: Composition of the reaction media for evaluation of lysine activity

The results are shown in Figures 9 to 12.

As shown in FIGS. 9 to 12, the three lysines Gter, Av-I and Nfar as well as the mixture of these three enzymes efficiently lysed the bacteria present in the various biological foams sampled at the water treatment station.

The use of the mixture of three lysines simultaneously ("lysine mix") shows an activity that is close to the average of the observed individual activities.

VI.2 Tests carried out with undiluted organic foams taken from water treatment plants and freeze-dried lysines

The lytic activity of the mixture of the three enzymes Gter, Av-I and Nfar ("lysine mix") in freeze-dried form was tested on samples of a type of biological foam (foam 5) taken in a water treatment plant . The relative presence of bacteria belonging to the genus Nocardia, Gordonia and Microthrix in this type of biological foams is shown in Table 5 below:

Table 5: Relative presence of bacteria belonging to the genus Nocardia, Gordonia and Microthrix in the different samples of biological foams tested. (-) absence of bacteria; (++++++) very important presence of bacteria.

The effect of the lysines was evaluated by observing the morphology of the filaments after incubation with samples of a type of biological foam (foam 5) taken at the water treatment plant with the mixture of the three enzymes ("lysine mix"). ) in freeze-dried form and labeled "Baclight" (differential labeling that distinguishes microorganisms with intact membranes from those whose membranes are degraded) combined with microscopic observation.

The results after 180 minutes of incubation without or with the "lysine mix" are shown respectively in FIGS. 13A and 13B.

In FIGS. 13A and 13B, the green color appears relatively white and the yellow-orange and red colors appear in gray.

After 180 minutes of incubation with the lysine mix, the green color disappears and yellow and red colored areas appear discontinuously along the length of the filaments, indicating that the mixture of the three enzymes Gter, Av-I and Nfar ( "Lysine mix") in the freeze-dried form effectively degrades the membrane of filamentous bacteria present in the biological foam samples taken at a water treatment plant.

These results indicate that the enzymes Gter, Av-1 and Nfar as well as the mixture of these three enzymes "lysine mix" makes it possible to fight effectively against filamentous bacteria responsible for the biological foaming by inhibiting their growth and degrading their membrane.

Claims

1. Agent for lysing at least one strain of filamentous bacteria characterized in that it comprises at least one polypeptide chosen from the following polypeptides:

h) polypeptide comprising at least one polypeptide as defined in e), f) or g).

2. Agent for lysis of at least one strain of filamentous bacteria according to claim 1 characterized in that it further comprises at least one polypeptide chosen from the following polypeptides:

d) a polypeptide comprising at least one polypeptide as defined in a), b) or c).

3. lysis agent according to claim 1 or 2, characterized in that it further comprises at least one polypeptide chosen from the following polypeptides:

i) a polypeptide whose amino acid sequence is one of the SEQ ID sequences

No. 1 or SEQ ID No. 3;

j) a polypeptide having a lytic activity and whose amino acid sequence has at least 80% identity with one of the sequences SEQ ID No. 1 or SEQ ID No. 3; k) a polypeptide having a lytic activity and whose amino acid sequence is that of a fragment of one of the sequences SEQ ID No. 1 or SEQ ID No. 3;

4. Non-therapeutic use of at least one polypeptide as defined in one of claims 1 or 2 or 3 for lysing at least one strain of filamentous bacteria.

5. Agent for preventing and / or combating biological foaming, characterized in that it comprises:

at least one enzyme capable of lysing at least one strain of filamentous bacteria involved in the biological foaming, said at least one enzyme comprising a polypeptide as defined according to claim 1; and or

at least one organism expressing said enzyme; and or

at least one bacterial lysate comprising said enzyme.

6. Agent for prevention and / or fight against biological foaming according to claim 5, characterized in that said at least one enzyme further comprises a polypeptide as defined according to claim 2 and / or a polypeptide as defined according to claim 3.

7. Agent for prevention and / or fight against biological foaming according to one of claims 5 or 6, characterized in that said strain of filamentous bacteria is included in the group comprising:

- bacterial strains of the family Nocardiaceae;

- strains of bacteria of the family Gordoniaceae;

strains of bacteria of the family including genus Microthrix;

- strains of bacteria of the family including the type of Eikelboom 0675;

- strains of bacteria of the family including the type of Eikelboom 0581.

8. Agent for prevention and / or fight against biological foaming according to any one of claims 5 to 7, characterized in that said at least one enzyme and / or said at least one organism expressing the enzyme is immobilized on a support.

9. Agent for prevention and / or fight against biological foaming according to any one of claims 5 to 8, characterized in that said at least one enzyme and / or said at least one organism expressing the enzyme and / or said at least one bacterial lysate is lyophilized.

10. Agent for prevention and / or fight against biological foaming according to any one of claims 5 to 9, characterized in that it comprises:

at least one organism expressing said first enzyme; and or

at least one bacterial lysate comprising said first enzyme;

said at least one first enzyme comprising a polypeptide as defined in claim 1; and

at least one organism expressing said second enzyme; and or

at least one bacterial lysate comprising said second enzyme;

said at least one second enzyme comprising a polypeptide as defined in claim 2; and

at least one organism expressing said third enzyme; and or

at least one bacterial lysate comprising said third enzyme; said at least one third enzyme comprising a polypeptide as defined in claim 3:

11. Kit for prevention and / or fight against biological foaming involving at least one strain of filamentous bacteria comprising:

at least one agent for preventing and / or combating biological foaming involving at least one strain of filamentous bacteria, said agent being defined according to any one of claims 5 to 10; and

at least one support adapted to immobilize said agent.

12. Use of at least one preventive agent and / or anti-foaming agent according to any one of claims 5 to 10 in the context of a water treatment process including a step of contacting said water with said at least one agent for preventing and / or controlling at least one strain of filamentous bacteria.

13. Use according to claim 12 characterized in that said water treatment process uses activated sludge.