Process for providing a culture of microorganisms to an elongated element

Abstract

The present invention relates to a process for depositing at least a culture of microorganisms to an elongated element, preferably a yarn, comprising the steps of: providing at least a first feeding device comprising at least a first outlet; supplying at least one elongated element to said at least first feeding device; feeding to said first outlet at least a first culture comprising at least one microorganism; dispensing said first culture from said at least first outlet; contacting at least part of said elongated element with said first culture of microorganisms, to provide at least a part of said elongated element with an amount of said first culture of microorganisms.

Claims

1. A process for depositing at least a culture (5) of microorganisms to an elongated element (2), comprising the steps of: a) providing at least a first feeding device (4) comprising at least a first outlet (7); b) supplying at least one elongated element (2), selected from a wire, a fiber, a thread, a yarn, a filament and combinations thereof to said at least first feeding device (4); c) feeding to said first outlet (7) at least a first culture (5) comprising at least one microorganism; d) dispensing said first culture (5) from said at least first outlet (7); e) contacting at least part of said elongated element (2) with said first culture (5) of microorganisms, to provide at least a part of said elongated element (2) with an amount of said first culture (5) of microorganisms; said process comprising the step of selectively varying the speed of said dispensing of said first culture (5) in function of the speed of supply of said elongated element (2), and/or as function of the absorption capacity, and/or the dimension of said at least one elongated element (2).

2. The process according to claim 1, wherein said first culture (5) of microorganisms is in liquid form and is dispensed from said first outlet (7) to said elongated element (2) discontinuously or continuously.

3. The process according to claim 1, wherein said elongated element (2) provided with said first culture (5) of microorganisms is collected at an elongated element take-up device (3).

4. The process according to claim 1, wherein said first culture (5) is dispensed to said elongated element (2) according to a direction that is substantially perpendicular to the direction of supply of said elongated element (2).

5. The process according to claim 1, wherein said elongated element (2) is fed to said outlet (7) at a distance whereby said culture (5) exiting said outlet (7) contacts both said outlet (7) and said elongated element (2) during said elongated element contacting step.

6. The process according to claim 5, wherein said distance is in the range of 0.1 mm to 5 mm.

7. The process according to claim 1, further comprising a step f) of incubating the elongated element obtained in said step e).

8. The process according to claim 7, wherein the elongated element obtained in said step e) is incubated in air and/or in an incubator (9).

9. The process according to claim 1, wherein at least a second outlet (17) is provided to dispense a second culture of microorganisms in liquid form or a culture medium.

10. The process according to claim 1, wherein at least said first culture (5) and/or culture medium is dispensed to said elongated element (2) within said incubator (9).

11. The process according to claim 1, wherein said culture (5) of microorganisms comprises at least one microorganism selected from bacteria, yeasts, fungi, algae and mixtures thereof.

12. The process according to claim 1, wherein said culture (5) of microorganisms comprises at least one microorganism able to provide a microbial product and/or a microbial precipitate onto the elongated element (2).

13. The process according to claim 12, wherein said microbial product is a biopolymer and/or an enzyme, and/or a dye, wherein said microbial product is selected from a sugar-based biopolymer, an amino acid-based biopolymer, and urease and wherein said dye is selected from indigo dye, indigoid dye, pigment dye and mixture thereof.

14. The process according to claim 12, wherein said microbial precipitate is calcite precipitate.

15. The process according to claim 1, wherein said culture comprises microorganisms at a concentration 1×108 CFU/ml to 1×109 CFU/ml.

16. The process according to claim 1, wherein said elongated element (2) is a yarn (2).

17. The process according to claim 1, wherein a wetting agent is fed to said elongated element, in an amount in the range of 0.05% to 1% by weight of the final culture weight.

18. An elongated element obtainable by the process of claim 1, wherein at least part of said elongated element is provided with a microbial product, and/or a microbial precipitate.

19. The elongated element according to claim 18, wherein said elongated element is dry and optionally dyed.

20. An apparatus for carrying out the process according to claim 1 comprising at least a first feeding device (4) having at least one first outlet (7) for dispensing at least a first culture (5) comprising at least one microorganism from said outlet (7), and at least one first elongated element source (1) to supply at least one elongated element (2) to said device, wherein said apparatus is configured so that said at least a first culture (5) comprising at least one microorganism contacts at least part of said elongated element (2) when said culture is dispensed from said first outlet (7).

21. The apparatus according to claim 20, further comprising at least one incubator (9).

22. The apparatus according to claim 20, further comprising at least a second feeding device (13) having at least one second outlet for dispensing a culture of microorganisms or a culture medium.

23. The apparatus according to claim 21, wherein said at least one incubator (9) includes said first feeding device (4), and/or said second feeding device (13), and/or at least one elongated element take-up device (3), wherein said elongated element take-up device (3) is configured to collect said elongated element after it has been provided with said culture (5).

24. The apparatus according to claim 20, further comprising a logic control unit configured to regulate the speed of dispensing of at least said first culture and/or the speed of supplying of said elongated element, and further comprising one or more sensors for monitoring culture at the outlet.

25. The apparatus according to claim 20, wherein said feeding device (4) comprise a pump (15).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 schematically illustrates an embodiment of the invention wherein an apparatus according to the invention dispensing a culture comprising microorganisms to an elongated element;

(2) FIG. 2 schematically illustrates an embodiment of the invention wherein an apparatus according to the invention comprises an incubator;

(3) FIG. 3 schematically illustrates an embodiment of the invention wherein an apparatus according to the invention comprises two feeding devices and two incubators;

(4) FIG. 4 schematically illustrates an embodiment of the plant according to the invention comprising four apparatuses according to the invention, which are positioned in parallel to each other;

(5) FIGS. 5 and 6 schematically show a particular embodiment of the invention, in which the incubator integrates an elongated element take-up device;

(6) FIG. 7 schematically shows a particular embodiment of the invention, which integrates a first feeding device;

(7) FIGS. 8 and 9 schematically show a particular embodiment of the invention, in which the incubator integrates the elongated element take-up bobbin and the feeding device for dispensing a culture comprising microorganisms, and/or a culture medium comprising nutrients to the elongated element;

(8) FIG. 10 shows an embodiment of the invention wherein the incubator integrates both the first feeding device and the second feeding device;

(9) FIG. 11 schematically shows an embodiment of the invention, in which the incubator integrates a plurality of elements configured to prolong the residence time of the elongated element in the incubator.

DETAILED DESCRIPTION OF THE INVENTION

(10) The invention will now be described with reference to FIGS. 1 to 11, wherein the present invention will be described with reference to exemplary embodiments wherein a culture comprising microbial cellulose producing microorganisms is provided to an elongated element, in particular to a yarn. In such Figures, reference is made to a yarn as the elongated element; however, as above discussed, different elongated elements may be used. As above discussed, the elongated element may be, for example, a fiber, a filament, a yarn, a thread, a wire and a combination thereof.

(11) Although in the following specific examples are provided, which refer to the use of bacteria for the production of microbial cellulose, it is to be noted that the scope of the present invention encompasses any culture of microorganisms which are able to produce a microbial product and/or a microbial precipitate onto the yarn. The culture of microorganisms may, for example, comprise at least one microorganism selected from bacteria, yeasts, fungi, algae and mixtures thereof. The microbial product produced by the microorganisms may be a biopolymer such as a sugar-based biopolymer, such as microbial cellulose or an amino-acid-based biopolymer, such as microbial collagen, or a mixture thereof.

(12) According to embodiments, the product of the microorganisms may be a precipitate (i.e., a product obtained by precipitation), such as a calcite precipitate. As above discussed, without being bound to a specific scientific explanation, it has been observed that the precipitation of calcite or calcium carbonate, is catalyzed by the enzyme urease, which can be advantageously produced by bacteria, such as bacteria of the Bacillus group.

(13) According to an aspect of the invention, any kind of microorganisms may be used, which produce a biopolymer or, as precipitants, cause the precipitation of any other substance which may provide the yarn with advantageous properties.

(14) According to embodiments, the product of the microorganisms may be a dye.

(15) According to embodiments, the dye, namely the dye that is produced by the microorganisms provided to the elongated element, is selected from indigo dye, indigoid dye, pigment dye and mixture thereof.

(16) As above mentioned, FIG. 1 schematically illustrates an embodiment of the invention wherein an apparatus according to the invention dispensing a culture comprising microorganisms to an elongated element, i.e., to a yarn.

(17) In FIG. 1, reference numeral 1 indicates an elongated element source 1, i.e., a yarn source 1, such as a yarn feeding bobbin, from which an elongated element 2, i.e., a yarn 2 may be substantially continuously supplied in the direction of a elongated element take-up device 3, i.e., a yarn take-up device 3, for example a yarn take-up bobbin, which collect the elongated element (i.e., the yarn) provided with a culture 5 comprising at least a microorganism, at the end of the process. The elongated element 2 may be a hydrophilic yarn, such as a cotton yarn.

(18) The culture 5 comprising microorganisms is provided onto the yarn 2 by first feeding device 4 through a first outlet 7.

(19) First feeding device 4, i.e., a microbial culture feeder, may comprise, for example, a first feeding pipe 6 containing a microbial culture 5, and a pump 15 to provide and regulate the dispensing of the culture 5 from the feeding pipe 6 through the first outlet 7. The first outlet 7 is, according to the embodiment of FIG. 1, positioned at one end of the feeding pipe 6 and may be, for example, a nozzle.

(20) The first feeding device 4 is positioned at a predetermined distance from the elongated element source 1 and are provided with a pump 15, preferably a syringe pump, a feeding pipe 6 and a first outlet 7, from which the culture 5 exits substantially in a perpendicular direction with respect to the supply direction of the yarn 2.

(21) According to the embodiment shown in FIG. 1, the culture 5 comprising microorganisms 5 is dispensed from the first outlet 7 so that the culture contacts both the yarn 2 and the outlet 7 substantially at the same time. Preferably, the feeding device 4 is configured so that the culture 5 is dispensed from the first outlet 7 in an amount that envelops the yarn (i.e., the elongated element) to form a half-drop 8, which contacts both the yarn 2 and the outlet 7 substantially at the same time, preferably at the same time. Advantageously, the feeding device 4 is configured so that the culture 5 is dispensed from the first outlet 7 in a substantially continuous manner, according to a pre-selected amount and/or speed in order to substantially avoid the culture, i.e., the half-drop 8 of culture 5 from dripping from the yarn 2, or from drying out on the outlet 7.

(22) According to embodiments, the first outlet 7 and the yarn 2 may be separated by a distance which is selected so that the culture 5 contacts both the outlet 7 and the yarn 5 when it is dispensed from the feeding device 4, According to embodiments, this distance may range from 0.1 mm to 5 mm, preferably from 0.5 mm to 2 mm. Advantageously, by adjusting the distance between the first outlet 7 and the yarn 2 and/or the speed of supply of the yarn 2 and/or the speed of dispensing the culture 5 (i.e., the flow rate of the culture 5 dispensed by the feeding device 4), advantageously, substantially the entire amount of the dispensed culture 5 may be provided to the yarn 2, preferably substantially continuously.

(23) According to embodiments, the microbial culture 5 may comprise microorganisms at a concentration of 1×10.sup.8 CFU/ml to 1×10.sup.9 CFU/ml, preferably ranging from 4×10.sup.8 CFU/ml to 6×10.sup.8 CFU/ml. In this case, advantageously, the concentration of the microorganism allows the production of the biopolymer and/or enzyme and/or precipitate and/or dye onto the elongated element in a short time.

(24) The elongated element source 1, i.e., the yarn source 1 and the elongated element take-up device 3, i.e., the yarn take-up device 3, are positioned with respect to the culture feeder 4 in such a way that the elongated element 2, i.e., the yarn 2, contacts the culture exiting from the outlet 7 by passing through the flow of culture 5, so that and the yarn 2 is impregnated with the microbial culture 5. In this way, advantageously, the yarn 2 picks up a predetermined amount of culture 5. Moreover, the speed of dispensing of the culture 5 and/or the speed of supplying of the yarn 5 may be adjusted so that the yarn 2 is homogeneously impregnated with the microbial culture 5 throughout its length. In other words, the speed of dispensing of the culture 5 and/or the speed of supplying of the yarn 2 may be adjusted so that a predetermined amount of culture 5 provided to the yarn 2 is substantially the same throughout the length of the yarn 2. Preferably, the amount of culture dispensed from the outlet 7 may be adjusted as function of the amount of the amount of culture 5 provided to the yarn 2 passing at the outlet 7, so that substantially the entirety (preferably the entirety) of the culture exiting from the outlet 7 is provided to the elongated element 2, i.e., to the yarn 2, preferably in a substantially continuous manner.

(25) The substantially continuous dispensing of the culture from the outlet 7 to a yarn 2, which may be substantially continuously supplied to the outlet 7, advantageously allows to provide substantially the entirety of the culture exiting from the outlet 7 to the yarn 2, thus effectively preventing the culture from dripping from the yarn 2, and, therefore, effectively preventing the production of culture waste.

(26) According to embodiments, the dispensing speed of the first culture 5 is varied according to the speed at which the elongated element 2 is supplied, and/or according to the absorption capacity of the elongated element 2 and/or the dimension of the elongated element 2. For example, the speed at which an elongated element 2 (i.e., a yarn 2) is supplied by the elongated element source 1 may range from 0.1 m/min to 10 m/min, preferably from 0.5 m/min to 5 m/min and more preferably from 0.8 m/min to 2 m/min.

(27) For example, the speed at which the microbial culture 5 is dispensed from the outlet 7 may range from 0.01 ml/min to 0.5 ml/min, preferably from 0.05 ml/min to 0.2 ml/min.

(28) According to embodiments, the speed at which the elongated element 2 is supplied is varied in function of to the dispensing speed of the first culture 5 (i.e., the flow rate of the culture 5 dispensed from the outlet 7 of the feeding device 4), and/or in function of the absorption capacity of the elongated element 2 (e.g., the yarn 2) and/or the dimension of the elongated element 2 (e.g., the yarn 2).

(29) After having received an amount of culture comprising microorganisms 5, the elongated element moves towards the take-up device 3. The feeding device 4 and the take-up device 3 are separated by a preselected distance, so that the elongated element 2 (e.g., the yarn 2) which has been provided with the microbial culture 5 is exposed to air for a predetermined period, which may range, for example, from 1 to 60 minutes. In this way, the elongated element (i.e., the yarn) is incubated in air, so that the microorganism on the elongated element are grown to produce the required amount of microbial product and/or of microbial precipitate. For example, a yarn 2 may be impregnated with a culture 5 comprising a biopolymer-producing bacteria and incubated in air in order to provide the yarn with a predetermined amount of biopolymer. For example, the biopolymer may be microbial cellulose produced by a bacterium, such as Acetobacter xylinum.

(30) In general, the amount of microbial cellulose that can be provided to an elongated element, e.g., a yarn, according to the process of the invention, is in the range from 0.05 to 0.15 g/m (i.e., grams of microbial cellulose for meter of elongated element, e.g., of yarn), preferably in the range from 0.07 to 0.13 g/m).

(31) According to embodiments of the invention, the amount of microbial cellulose is in the range from 0.05 to 0.08 g/m.

(32) According to embodiments of the invention, the amount of microbial cellulose is in the range from 0.08 to 0.15 g/m.

(33) For example, in the following table (Table 1) examples of air incubation periods for different weights of microbial cellulose yield, for the same amount of microbial culture provided to a cotton yarn are listed.

(34) TABLE-US-00001 TABLE 1 Cotton yarn (10/1) Incubation period Weight of microbial weight (min.) cellulose (g) 100 g 1 0.2 100 g 10 2 100 g 30 6 100 g 60 12

(35) According to embodiments, the microbial culture 5 may comprise different microorganisms, i.e., may be a co-culture of microorganisms. For example, the microbial culture may comprise both biopolymer-producing microorganisms and dye-producing microorganisms. In this case the elongated element 2 (e.g., a yarn 2) may be impregnated with the culture 5 comprising both biopolymer-producing microorganisms and dye-producing microorganisms, and then incubated, in air and/or in an incubator, in order to provide the elongated element 2 with a dyed biopolymer.

(36) For sake of simplicity, in the present Figures, reference numeral 5 indicates a microbial culture that has been provided to the elongated element, for example to a yarn. In other words, reference numeral 5 in the present Figures indicates an elongated element (e.g., a yarn) that has been provided at least with a first microbial culture.

(37) Also, for sake of clarity, in present FIGS. 5-11, the incubator is schematically represented as a transparent box, in order to show the elements that are placed inside the incubator in the different represented exemplary embodiments.

(38) The size of the half-drop 8 of microbial culture (i.e., the volume occupied by the culture at the outlet 7) may be measured, according to known methods, and the flow rate of the culture to form the half-drop 8 may be adjusted in order to provide a predetermined quantity of microbial culture 5 at the outlet 7 and to the elongated element 2, for example, when the elongated element is a yarn, according to the yarn diameter, absorption capacity of the yarn and yarn hairiness/fluffiness and/or hydrophilic/hydrophobic properties. In this way, advantageously, it is possible to deposit onto the elongated element 2 substantially the entirety of the culture 5 dispensed from the outlet 7, substantially in a continuous manner, substantially avoiding the culture from falling down from the outlet 7 and/or from the elongated element 2, and being wasted.

(39) The adjustment of the size of the culture half-drop 8 may be performed continuously during the process, for example, according to a negative feedback, or pre-emptively, before each production run, based on previously collected data.

(40) For example, advantageously, the apparatus may further comprise a logic control unit configured to regulate the flow rate of the culture. For example, one or more sensor may provide a signal indicative of the amount of culture exiting the outlet 7 of the feeding device 4, e.g., the size of the half-drop 8 at the outlet 7.

(41) According to embodiments, the logic control unit may be advantageously configured to control (e.g., adjust) the speed of dispensing of at least said first culture from the feeding device 4 and/or the speed of supplying the elongated element 2 (e.g., a yarn 2) from the elongated element source 1, in function of the signal coming from at least one sensor, according to a negative feedback.

(42) Examples of continuous negative feedback loop adjustment systems comprise, in a first embodiment, a laser light passing below the half-drop and forming an optical path between a laser source and a light sensor so that the pump feeding the culture may be slowed down or the elongated element (e.g., yarn) supply speed may be varied in case the drop size exceeds a particular threshold and prevents the laser light from reaching the light sensor.

(43) According to embodiments, additionally or alternatively to the laser, the adjustment may be provided by image processing using a suitable algorithm based on an open source library (e.g. OpenCV library), in order to provide a feedback loop which regulates the size of the half-drop at the outlet.

(44) Additionally or alternatively, according to embodiments, a capacitive sensor is used for measuring the distance between the half-drop 8 and a reference level and thus providing the feedback loop.

(45) Additionally or alternatively, according to embodiments, a possibility to regulate the amount of the culture 5 comprising microorganisms to be dispensed is to dynamically measure the elongated element humidity, e.g., the humidity of a yarn, after impregnation with the culture, and correspondingly adjust the pump speed.

(46) According to embodiments, additionally or alternatively, for example, a calibration of the system before each production run, in order to determine the absorption rate of the elongated element (e.g., the yarn) to be used and accordingly set the pump speed and/or the elongated element speed, and thus the amount of required culture medium for the current run, may be performed. In this case, advantageously, the need of a feedback control may be substantially reduced.

(47) According to embodiments, a wetting agent may be provided to the elongated element. Advantageously, the concentration of the wetting agent may be adjusted, in order to reach the desired injection speed, depending on hydrophilic/hydrophobic properties of the elongated element, which may be pre-determined according to known methods. According to embodiments, the wetting agent may be added directly to the culture 5 comprising at least one microorganism before its injection onto the elongated element (e.g., a yarn).

(48) Additionally or alternatively, the wetting agent may be fed into the one or more incubators, as discussed in the following. According to embodiments, the wetting agent may be provided within the culture in an amount ranging from 0.05% to 1% by weight of the final culture weight, more preferably ranging from 0.1% to 0.5% by weight of the final culture weight.

(49) FIG. 2 shows an embodiment of the apparatus according to the invention, wherein an incubator 9 is provided along the elongated element path, downstream with respect to the feeding device 4. The incubator 9 provides, in a way that is known per se, a suitable environment for culturing and growing the microorganisms on the elongated element 2, e.g., a yarn 2. In particular, the incubator provides a suitable environment for keeping the elongated element humid and preventing the drying of the culture during incubation. Moreover, one or more medium supplements, e.g., comprising nutrients and/or wetting agents may be fed into the incubator to further promote the growth of the microorganisms. Also, advantageously, when an incubator is used, the temperature of incubation may be pre-selected and set according to, for example, the microorganism to be grown.

(50) For example, if the microorganism is a microbial cellulose-producing microorganism, during incubation (in air and/or in incubator) microbial cellulose is produced and provided onto the elongated element.

(51) For example, if the microorganism is a urease-producing microorganism, during incubation (in air and/or in incubator) urease is produced and provided onto the elongated element. In this case, advantageously, in the presence of a suitable culture medium, the precipitation of calcium carbonate from the medium onto the elongated element may be obtained.

(52) For sake of simplicity, the present Figures schematically show a yarn (i.e., an exemplary elongated element) moving according to a straight path (for example, inside the incubator). However, according to embodiments, the yarn may take different paths, inside and/or outside the incubator. For example, the path of the yarn may comprise curves and/or serpentines and/or switching of path's level, so that the yarn moves according to a “multilevel” or “tridimensional” path.

(53) Advantageously, by varying the path of the elongated element within the incubator, the residence time of the elongated element in the incubator may be varied, e.g., prolonged.

(54) For example, the longer is the path of the elongated element within the incubator, the longer is the residence time of the elongated element within the incubator, at a predetermined speed of the elongated element.

(55) As above mentioned, according to embodiments, the incubator may integrate one or more elements configured to prolong the residence time of the elongated element in the incubator, such as elements configured to change the direction of the elongated element in the incubator and/or elements configured to partially wind the elongated element (e.g., a yarn) inside the incubator.

(56) FIG. 3 shows another embodiment of the apparatus according to the invention, wherein two incubators, i.e., a first incubator 10 and a second incubator 11, and two microbial culture feeding devices, i.e. a first feeding device 12 and a second feeding device 13, are positioned in series, one after the other, along the path of the elongated element. According to the embodiment shown in FIG. 3, the first feeding device 12 dispenses a first culture comprising microorganisms 5 to an elongated element 2 (e.g., to a yarn 2). The elongated element provided with the culture 5 is then incubated for a predetermined time in the first incubator 10. During incubation, the microorganisms are cultured and grown. For example, if the microorganism is a microbial cellulose-producing microorganism, during incubation microbial cellulose is produced onto the elongated element 2. After having exited the first incubator 10, the elongated element 2, already provided with a first amount of culture 5, is contacted with a second “half-drop” 14 of a liquid, dispensed from a second feeding device 13. The second feeding device 13 may dispense again the first culture 5, or a suitable culture medium (i.e., the liquid medium without the microorganisms), or a second culture of microorganisms, different from the first culture dispensed by the first feeding device 12, Subsequently, the elongated element (e.g., a yarn) enters the second incubator 11, where it undergoes a second incubation period. In this way, the amount of microorganisms or culture medium deposited on the elongated element may be increased, in order to fulfil particular needs. For example, if a culture comprising microbial cellulose-producing microorganisms is dispensed both from the first feeding device 12 and the second feeding device 13, microbial cellulose is produced onto the yarn two times, i.e., during a first incubation in the first incubator 10 and during a second incubation in the second incubator 11. Analogously, if a culture comprising microbial cellulose-producing microorganisms is dispensed from the first feeding device 12 and a culture medium is dispensed by the second feeding device 13, microbial cellulose is produced onto the yarn two times, during the two steps of incubation.

(57) For example, if a culture comprising microbial cellulose-producing microorganisms is dispensed from the first feeding device 12 and a culture comprising dye-producing microorganisms (e.g., indigo-producing microorganisms) is dispensed from the second feeding device 13, microbial cellulose is produced onto the elongated element first, i.e., during a first incubation in the first incubator 10, and dye is produced during a second incubation in the second incubator 11. In this way, a dyed biopolymer (e.g., an indigo dyed microbial cellulose) may be obtained, onto the elongated element, according to a two step process.

(58) According to this embodiment of the invention, the process can be defined as a “consecutive” process, wherein the production of the biopolymer and the production of the dye, i.e., the dye molecules, occur substantially sequentially. According to embodiments, biopolymer-producing microorganisms are not removed from the biopolymer before providing dye-producing microorganisms. In this case, advantageously, the thickness of the biopolymer layer increases because the biopolymer-producing microorganisms are still present on the elongated element, when the culture of dye-producing microorganisms is provided.

(59) Additionally or alternatively, according to embodiments, a culture medium comprising nutrients may be injected onto the elongated element or directly on the elongated element feeding bobbin. According to embodiments, other feeding devices and/or outlets (e.g., nozzles) may be additionally placed along the path of the elongated element to supply nutrients in order to further promote the growth of the microorganisms and, for example, the production of a biopolymer onto the elongated element, e.g., to provide a thick layer of biopolymer (such as, microbial cellulose) to the elongated element (e.g., a yarn).

(60) FIG. 4 schematically shows an embodiment of the plant of the invention. In particular, FIG. 4 shows a schematic arrangement of four apparatuses according to the present invention. For sake of simplicity, FIG. 4 shows four apparatuses according to the embodiment discussed with reference to FIG. 2, wherein the four apparatuses are arranged in parallel. When a plurality of apparatuses according to the invention are used, advantageously, a plurality of elongated elements, e.g., yarns, may be provided with one or more cultures of microorganisms substantially at the same time. The different feeding devices may dispense the same or different cultures. The elongated elements 2 may be the same, or may be different elongated elements. The elongated elements 2 may have the same or different features, and may be incubated in the same conditions or in different condition in the different incubators 9. When a plurality of apparatuses according to the invention are used, advantageously, a plurality of elongated elements 2 (e.g., yarns 2) may be provided with different features substantially at the same time. For example, a first yarn 2 may be provided with a predetermined amount of microbial cellulose. A second yarn 2 may be provided with a greater or a lower amount of microbial cellulose with respect to the first yarn. A third yarn 2 may be provided with a predetermined amount of calcite precipitate, and a fourth yarn 2 may be provided with a greater or lower amount of calcite precipitate with respect to the third yarn 2. All other aspects of the apparatus discussed with reference to schematic FIG. 2 apply mutatis mutandis to each of the four apparatuses of the plant schematically represented in FIG. 4.

(61) According to the embodiment of FIG. 4, in each apparatus according to the invention provides a culture of microorganisms to a single elongated element 2, e.g., a single yarn 2. In other words, the outlet of the feeding device of each apparatus according to the invention dispenses, for example, a culture of microorganisms, to a single elongated element 2, e.g., to a single yarn 2.

(62) FIGS. 5 and 6 schematically show an incubator according to a particular embodiment of the apparatus of the invention, in which an elongated element take-up device 3 (e.g., a yarn take-up device 3) is integrated within the incubator 9.

(63) Particularly, FIG. 5 is a lateral view of an incubator 9, while FIG. 6 is a frontal view of the incubator 9. The incubator in FIG. 6, with respect to FIG. 5, is observed from a point of view according to arrow A.sub.1.

(64) Also, arrow A.sub.1 schematically represents the direction according to which the elongated element (e.g., a yarn) provided with a culture 5, comprising at least one microorganism, is supplied to the incubator 9.

(65) According to the embodiment illustrated in FIGS. 5 and 6, the incubator 9 is provided with an elongated element take-up device 3 (e.g., a yarn take-up device 3), for example a bobbin, for collecting the elongated element after that it has been provided with a culture 5 comprising microorganisms. The incubator 9 provides for suitable environmental condition such as, for example, temperature and humidity, for the growing of the microorganisms in the culture 5 onto the elongated element and, according to embodiments, the production of microbial products and/or microbial precipitates and/or dyes, such as biopolymers (for example microbial cellulose), calcite, or indigo.

(66) FIG. 7 schematically show an incubator 9 according to a particular embodiment of the invention, which integrates a first feeding device 4.

(67) According to FIG. 7, arrow A.sub.2 schematically represents the direction according to which the elongated element 2 (e.g., a yarn 2) is supplied, for example from an elongated element source, to a first feeding device 4, which is integrated in the incubator 9.

(68) According to the embodiment shown in FIG. 7, the culture 5 comprising microorganisms is dispensed from the first outlet 7 so that the culture contacts both the elongated element 2 (i.e., the yarn 2) and the outlet 7 substantially at the same time. Feeding device 4 is configured to dispense a first culture 5 comprising at least one microorganisms from the first outlet 7, as previously disclosed. Culture liquid 5 contacts the elongated element 2, so that the culture 5 is provided to the elongated element 2. After the elongated element 2 has been provided with a predetermined amount of microbial culture 5, it moves outside the incubator 9. According to FIG. 7, arrow A.sub.3 schematically represents the direction according to which the elongated element exits from the incubator 9.

(69) According to embodiments, after that the elongated elements exits the incubator 9, it may be further provided with a second culture comprising microorganism and/or with a culture medium.

(70) According to embodiments, after that the elongated elements exits the incubator 9, it may be collected with an elongated element take-up device, such as a yarn take-up bobbin.

(71) FIGS. 8 and 9 show an embodiment of the apparatus of the invention, in which a particular form of the one or more incubators that may be used is shown.

(72) Particularly, FIG. 8 is a lateral view of an incubator 9, while FIG. 9 is a frontal view of the incubator 9. The incubator in FIG. 9, with respect to FIG. 8, is observed from a point of view according to arrow A.sub.4.

(73) Also, arrow A.sub.4 schematically represents the direction according to which the elongated element 2 (e.g., a yarn 2) enters into the incubator 9, wherein the elongated element 2 is contacted with a culture 5 comprising at least one microorganism, which is supplied by a first feeding device 4, through a first outlet 7, to the elongated element 2.

(74) In the embodiment schematically represented in FIGS. 8 and 9 of the apparatus of the invention, the incubator 9 is provided with an elongated element take-up device 3, (for example, a bobbin may be selected as a particular device for collecting the elongated element, for example a yarn), and with a first feeding device 4. In this case, the first feeding device 4 and the elongated element take-up device 3 are integrated in the incubator 9.

(75) According to the embodiment of FIGS. 8 and 9, a yarn 2 is supplied, for example by a yarn source, and enters into the incubator 9. Inside the incubator 9, a culture 5 comprising microorganisms is dispensed to the yarn 2 from the first outlet 7 of the first feeding device 4. After the yarn 2 has been provided with a predetermined amount of microbial culture 5, it is collected by a yarn take-up device 3, inside the incubator 9.

(76) As above mentioned, in the exemplary embodiment illustrated in FIGS. 8 and 9, a first feeding device 4 is shown, which provides a first culture 5 comprising microorganisms to an elongated element 2, i.e., to a yarn 2.

(77) According to embodiments, in addition to the shown first feeding device 4, at least a second feeding device for the feeding of a second microbial culture and/or a culture medium comprising nutrients may be integrated into the incubator 9.

(78) According to advantageous embodiments, the present invention allows for the production of an elongated element, e.g., a yarn, which may be provided at least in part with a microbial product (for example, a biopolymer, such as microbial cellulose) and/or a microbial precipitate, such as calcite. Such elongated elements, e.g., yarns, may be advantageously used for the production of fabrics and garments. Also, advantageously, a yarn which has been provided with a biopolymer, e.g., microbial, cellulose may be dyed, e.g., indigo dyed. Dyeing of elongated elements (e.g., yarns) provided with, for example, microbial cellulose, may be performed according to techniques that are, per se, known in the art.

(79) FIG. 10 shows an embodiment of the invention wherein the incubator 9 integrates both a first feeding device 12 and a second feeding device 13.

(80) In the embodiment of FIG. 10, a first feeding device 12 and a second feeding device 13, are positioned in series, one after the other, along the elongated element path, and are both integrated into the incubator 9, so that at least a first culture 5 comprising microorganisms is dispensed to the elongated element 2 inside the incubator 9.

(81) In FIG. 10, the arrow A.sub.5 schematically represents the direction according to which the elongated element 2 (e.g., a yarn 2) is supplied, for example from an elongated element source, to the incubator 9. The incubator comprises a first feeding device 12 and a second feeding device 13. The culture 5 comprising microorganisms is dispensed from the first outlet 12, through its first outlet 16, to the yarn 2. The first feeding device 12 dispenses a first culture 5 comprising at least one microorganism to the yarn 2.

(82) Subsequently, the yarn 2, provided with a first amount of culture 5, is contacted with a second culture liquid 14, dispensed from a second feeding device 13, through a second outlet 17. For example, the second feeding device 13 may supply again the first culture 5, or a suitable culture medium comprising nutrients for the microorganisms already provided to the yarn 2 (i.e., the liquid medium without the microorganisms), or a second culture of microorganisms, different from the first culture dispensed by the first feeding device 12. Subsequently, the yarn exits from the incubator 9, according to a direction schematically represented by the arrow A.sub.6.

(83) FIG. 11 schematically shows an incubator 9, which integrates a plurality of elements 18 configured to prolong the residence time of the elongated element in the incubator 9.

(84) According to the embodiment of FIG. 11, an elongated element (e.g., a yarn) that has been provided with a culture 5 of microorganisms enters into an incubator 9.

(85) FIG. 11 schematically shows a lateral view of the incubator 9.

(86) Inside the incubator 9, a plurality of elements 18 configured to prolong the residence time of the elongated element in the incubator 9 are present.

(87) In particular, elements 18 are elements that are configured to change the direction of the elongated element, i.e., configured to deviate the elongated element (i.e., the yarn), in the incubator 9.

(88) For example, elements 18 configured to prolong the residence time of the elongated element in the incubator 9 may be pulleys and/or bobbins, and may be preferably rotatable elements.

(89) FIG. 11 shows an embodiment wherein the elements 18 configured to prolong the residence time of the elongated element inside the incubator 9 deviate the elongated element according to a path which substantially define a serpentine.

(90) The incubator 9 includes twelve elements 18 configured to prolong the residence time of the elongated element in the incubator, which are distributed in two series, a first (e.g., upper) series comprising six elements 18, and a second (e.g., lower) series, comprising six elements 18.

(91) According to the embodiment illustrated in FIG. 11, a yarn that has been provided with a culture 5 of microorganisms enters into an incubator 9, and contacts a first element 18 in the first (e.g., upper) series. The yarn is deviated to a second element 18, in the second (e.g., lower) series. The yarn contacts the second element 18 and is deviated to contact a third element 18 in the first series of elements, and subsequently to another element 18 in the second series and again to another element 18 in the first series, and so on until the last element 18. In other words, according to the embodiment illustrated in FIG. 11, the yarn (i.e., the elongated element) sequentially contacts a plurality of elements 18, preferably all the elements 18, alternating one element 18 of the first (e.g., upper) series to an element 18 of the second (e.g., lower) series.

(92) After contacting the last element 18, the yarn exits from the incubator 9.

(93) According to embodiments, elements 18 may be configured to partially wind the elongated element inside the incubator. For example, the elongated element may be wound around a first element 18 one or more times before contacting a second element 18. In this case, the residence time of the elongated element in the incubator in further prolonged.

(94) According to embodiments, the elongated element which exits from the incubator is provided at least in part with an amount of a microbial biopolymer (e.g., microbial cellulose) and/or an amount of a microbial precipitation (e.g., calcite precipitation). Advantageously, the elongated element (e.g., a yarn) which exits from the incubator is provided with an amount of a microbial biopolymer and can be dyed, for example, through common dyed processes.

EXAMPLES

(95) In the following examples, yarn samples was used as elongated element to carry out the process of the invention.

Example 1

(96) A first experiment was carried out using the process and apparatus according to the invention, in which a microbial (bacterial) culture was injected onto yarn samples and the final dry yarn weight was measured in order to determine the amount of microbial (bacterial) cellulose deposited on the yarn. The experiment involved the following steps: About 25 g of yarn were provided on a suitable bobbin. 1200 ml of bacterial culture (BC) of Gluconacetobacter were incubated for 2 days at 200 rpm and 28° C. The bacterial cellulose culture was filtered by using a scrim in order to remove cellulosic fibers (produced during the incubation period). 1200 ml of culture were centrifuged at 5000 rpm for 15 minutes and concentrated in order to form a culture having a high concentration of 5.4×10.sup.8 CFU/ml. 0.5 wt.-% of wetting agent were added to the culture. By using a syringe pump the concentrated culture was injected onto yarn samples (pump speed: 0.1 ml/min, unwinding speed of yarn source bobbin was fixed by voltage used (1.3V)). The yarn provided with the culture Gluconacetobacter was incubated for about 10 minutes in air on a 5-meter-long bench. Thereafter, the yarns coated with the bacterial culture were washed with 0.1 M NaOH solution at 80° C. for 20 minutes and neutralized in distilled water. The weight of the yarns, after being dried at room temperature, was measured and the amount of bacterial cellulose deposited on the yarn was determined as being equal to 8.12% with respect to the initial weight of the yarn.

(97) In general, according to embodiments of the invention, the amount of microbial cellulose added may be in the range of 0.05 to 0.08 g/m.

(98) Advantageously, the dried yarn provided with microbial cellulose may be dyed, e.g., indigo dyed, and used in the production of fabrics and/or garments.

Example 2

(99) In a second experiment that was carried out, a bacterial culture was prepared and applied to a yarn as disclosed in the previous Example 1. After the bacterial culture injection onto the yarn, the yarn was wound around a yarn take-up bobbin, which was placed inside an incubator. The yarn provided with the injected bacterial culture was incubated in the incubator. Nutrients were supplied to the yarn inside the incubator by a feeding device. The amount of bacterial cellulose deposited onto the yarn was determined as being equal to 13% with respect to the initial weight of the yarn.

(100) According to embodiments, the amount of microbial cellulose provided may be in the range from 0.08 to 0.15 g/m.

(101) As above mentioned, the dried yarn provided with microbial cellulose may be dyed, e.g., indigo dyed, and used in the production of fabrics and/or garments.

Example 3

(102) A third example of a process according to the invention involves the use of microbially induced calcium carbonate (CaCO.sub.3) precipitation (MICP) by a culture of Bacillus sp. cells in an urea-CaCl.sub.2) medium containing 3 g/L of nutrient broth (Difco), 10 g/L NH.sub.4Cl, and 2.12 g/L of NaHCO.sub.3 (equivalent to 25.2 mM adjusted to pH 6.0 with 6 N HCl).

(103) Methods and condition of supplying and culturing disclosed in above Examples 1 and 2 apply mutatis mutandis to Example 3.

(104) By providing a yarn with a microbial precipitate, in particular calcite precipitate, advantageously, it is possible to increase the tensile strength of the yarn. Another advantageous effect of microbial calcite precipitation is that calcite provides for a whitening of the yarn. In this way, a yarn which can be easily dyed may be obtained.

(105) Also, the present invention advantageously provides for an environmentally friendly way of processing yarns with respect of conventional processes, substances which may pollute the environment are used.

(106) The dried yarn obtained may be used in the production of fabrics and/or garment.

(107) The present invention provides a novel process for providing, in a substantially continuous, homogeneous, reproducible, contamination-free way, an elongated element, for example a yarn, such as a cotton yarn, with a culture of microorganisms, which preferably produce biopolymers such as microbial cellulose and/or microbial precipitates such as calcite precipitate, and/or dyes such as indigo, which may be provided to at least part of the elongated element to provide the elongated element with advantageous characteristics, as above discussed. The process of the invention allows for the production of, for example, yarns that are suitable to be used in the textile field, in particular in the manufacture of fabrics and garments. The invention is not limited to the embodiments disclosed in the previous description, which are only illustrative and non-limiting, but may be subject to modifications and variants, as envisaged by the skilled in the art, within the protection scope, which is defined by the appended claims.