WO2012045133A1 - Photobioreactor and kit for the culture of photosynthetic microorganisms, production of biomass, scavenging and use of pollutant gases as a food source for photosynthetic microorganisms - Google Patents

Abstract

The present invention relates to the development of a photobioreactor aimed at carrying out biotechnologial processes involving photosynthetic microorganisms, a kit comprising a photobioreactor and a complementary system, and to the uses of the kit for cultivating microorganisms, producing biomass, scavenging and using pollutant gases as a food source for photosynthetic microorganisms. The design and arrangement of the photobioreactor are crucial factors for the effectiveness of the system to scavenge gases and produce biomass, the present invention providing an arrangement that increases process yield and reduces operation costs, as well as equipment manufacturing and maintenance costs.

Description

 Descriptive Report

 PHOTOBIORREATOR AND KIT FOR CROPPING OF PHOTOSYNTHETIC MICROORGANISMS, OBTAINING BIOMASS, SEQUESTRESS AND USE OF POLLUTANT GASES AS A NUTRITIONAL SOURCE OF PHOTOSYNTHETIC MICROORGANISMS.

FIELD OF INVENTION

The present invention relates to the development of a photobioreactor for performing biotechnological processes involving photosynthetic microorganisms. The second object of the invention relates to a kit composed of a photobioreactor and the complementary system comprising a tank, a biomass filter, a riser, gas storage tanks and an excess gas separator. Finally, the third object of the invention concerns the use of the microorganism cultivation process kit, biomass and sequestration and the use of polluting gases as a nutritional source for photosynthetic microorganisms.

TECHNICAL STATE

At the current juncture, the use of petroleum fuels is recognized as unsustainable. This is due both to the instability of its price resulting from numerous conflicts and disputes in several of its producing countries, as well as to the imminent depletion of natural oil reserves and the release of carbon dioxide (C0 ₂ ) into the atmosphere. Growing industrialization and urbanization worldwide increase the demand for energy, and energy generally comes from burning fossil fuels. With Thus, the emission of atmospheric pollutants such as carbon dioxide, sulfur oxides and nitrogen oxides has been growing considerably. This increase in air pollution is a determining cause of the greenhouse effect.

 It is known that the greenhouse effect is one of the main causes of global warming we have witnessed. In addition, carbon dioxide is the major contributor to the aggravation of the greenhouse effect. It is speculated that, given the current rate of release of pollutant gases into the atmosphere, the earth's temperature may rise between 1.5 ° C and 4.5 ° C until the end of the century. This increase would be extremely detrimental to the terrestrial biosphere and could cause extinction of various species, reduced agricultural production, shortage of drinking water, increased occurrence of natural disasters and sea levels, and may even submerge coastal cities and entire countries.

As for nitrogen oxides, they are responsible for ozone depletion (0 ₃ ) in the terrestrial stratosphere (ozone layer). Moreover, nitric acid, its derivative, is one of the components that causes acid rain (precipitation with high concentration of hydrogen ions - H ⁺ ) and, consequently, has adverse effects on forests, soil, rivers and biodiversity (mainly insects and aquatic life), as well as harming human health, monuments and buildings.

 Sulfur oxides, in addition to being reactive precursors of sulfuric acid, also implicated in acid rain, are associated with various respiratory diseases and their symptoms.

Because of all these risks, several alternatives to reduce the harmful effects of using these fuels are constantly researched. One such alternative is the replacement of fossil fuels with biofuels (renewable fuels). These can be obtained through chemical reactions between oils and alcohols, and these oils are likely to come from oil plants such as soybeans, corn and palm. However, it is believed that the cultivation of these plants for biofuel production would compete for large areas of land to produce food for the market. On the other hand, biofuels derived from photosynthetic microorganisms come at this juncture as solutions to these problems. This is because, in addition to capturing carbon dioxide and other noxious gases such as nitrogen oxides (NO _x ) and sulfur oxides (SO _x ) from the atmosphere, as well as other oilseeds can do, they require less cultivation area. for the same supply of lipids, their precursors. In addition, cultivation can occur in environments hostile to other crops, such as high salt water, eliminating the need for freshwater use for domestic or industrial use, and on low-fertile land unfit for growing food. .

Photosynthetic microorganisms require solar energy to make photosynthesis, a metabolic process in which they use carbon dioxide (inorganic carbon) to produce organic carbon and release oxygen gas as a reaction product. In addition, they require sulfur sources for the production of sulfur compounds and nitrogen for protein and amino acid synthesis. These compounds may be introduced into the culture as gases from the combustion of other fuels (fossil or renewable). The specialized technical literature presents some examples of photobioreactors and / or bioreactors and / or reactors, both for biomass production purposes and related to the sequestration of pollutant gases, derived or not from the burning of fuels.

 In patent application WO 2009/069967, a photobioreactor for large scale microalgae culture is described. Two of the shortcomings of the subject matter described in the above document are the impossibility of using sunlight as a light source for cultivation, resulting in higher costs and energy expenditure; and the impossibility of cultivating other photosynthetic microorganisms except microalgae in the described photobioreactor. In addition, reactor assembly would be expensive and time consuming to use materials not commonly available on the market.

 In patent application WO 99/61577, a closed photobioreactor for culturing microorganisms for the purpose of producing food, for humans or animals, and for pharmaceutical and / or cosmetic uses is described. This photobioreactor would be dependent on sunlight (inability to use artificial light in the process). Moreover, in this project, the culture filtration would only occur when it reached a predetermined concentration of cells, thus preventing a continuous biomass production of photosynthetic microorganisms.

In patent application WO 2008/079724, a photobioreactor for culturing microalgae or cyanobacteria is described. Two of the problems encountered in this project are the fact that thermal regulation occurs when bathing the cultivation chamber in water of predetermined temperature which would drastically reduce the possibility of handling the apparatus and increase the risk of contamination of the medium if the chamber ruptures; and the fact that solar radiation can only be used as a light source to the detriment of artificial light sources (needed in places with low natural light). In addition, the use of a pumping system for photobioreactor circulation of the medium may be stressful to the crop, and it is preferable to use other methods such as the airlift employed in the present invention which in addition to providing sufficient energy for the circulation of the medium may still be the source of gaseous nutrients necessary for the growth of photosynthetic microorganisms.

 In Brazilian patent applications PI0702736-2 and PI0701842-8, tubular photobioreactors (serially or not linked) for the removal and / or fixation of polluting gases using microalgae and / or cyanobacteria are described. These documents propose to increase the scale without increasing the number of photobioreactors in series, tubular reactors up to 50 meters high; This would make handling and repair of the appliance extremely difficult. In addition, no parallel associations of tubular photobioreactors are proposed, which would be a solution for scaling up with better terrain.

The present invention has as features solutions to the above problems, such as alternative light source (artificial or natural) and the use of photosynthetic microorganisms in production. In addition, parallel and series associations of photobioreactor cells and stages are proposed to make better use of the production space. SUMMARY OF THE INVENTION

The present invention relates to a photobioreactor for performing biotechnological processes involving photosynthetic microorganisms.

 The second object of the invention relates to a kit composed of a photobioreactor and a complementary system comprising a tank, a biomass filter, a riser, gas storage tanks and an excess gas separator.

 Finally, the third object of the invention concerns the use of the kit for the cultivation of photosynthetic microorganisms, the obtaining of biomass for later biofuel production through the cultivation of photosynthetic microorganisms and sequestration, and the use of polluting gases as a nutritional source for photosynthetic microorganisms.

 Biotechnological applications and processes involving photosynthetic microorganisms, the photobioreactor and kit of the present invention, cited herein, are preferred embodiments and should not be construed as limitations on the subject matter of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS Figures 1A and 1B show a top and another perspective schematic view of a preferred photobioreactor cell embodiment of the present invention, respectively.

Figures 2A, 2B and 2C show top schematic views of a preferred embodiment of input, intermediate and output modules, respectively. Figure 3 shows a schematic representation of the cultivation equipment of the present invention.

 Figure 4 shows a schematic top view of a preferred embodiment of associating square-shaped photobioreactor cells.

 Figures 5A and 5B show schematic top views of another preferred embodiment of photobioreactor cell association. Thus, cells are associated in modules (input, intermediate and output) and they are associated in series to form the photobioreactor.

 Figures 1A, 1B, 2A, 2B, 2C, 3, 4, 5A and 5B are merely preferred embodiments of the present invention and are not to be construed as limiting thereof.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a photobioreactor for performing biotechnological processes involving photosynthetic microorganisms. These processes may have as functionality to promote the growth of photosynthetic microorganisms.

 For a better understanding of the process of cultivation of photosynthetic microorganisms and their detailed description, some definitions will be given above.

Cultivation cell of the preferred embodiment is defined as the set of four cultivation columns and four tube bundles connecting them as edges of a quadrilateral, where the columns are the vertices. These beams may have a number of tubes ranging from one to the maximum allowed by the available space and the maximum column height (determined by a person skilled in the art to have maintenance of equipment). A top view representation of a cell of this embodiment can be seen in Figure 1A. Figure 1B presents the perspective view of this culture cell. In addition, they are defined as input column at 101; columns 102.1 and 102.2 as intermediates and 103 as the output column. When interconnected with others, the cell can receive crop flow in either column. Therefore, the perspective view may have tube bundles on all faces of the cell columns. Such tube bundles may have any number of transparent tubes, not limited to seven, as shown in Figure 1B. In addition, not all bundles need to have the same number of tubes, which is adjusted according to the sizing of the entire system by one of ordinary skill in the art. Although there is this preferred embodiment, the cell may have different geometric shapes and the number of tube bundles varies with the determination of this shape.

 Also defined as input module is the set of columns and beams, whose top schematic view is shown in Figure 2A. This set represents three cells, one of which receives the culture flow from equipment external to the photobioreactor. The other two are supplied from the culture medium by the first cell, with which they share two columns and a bundle of tubes each.

An intermediate module is also defined as the set of columns and beams, whose top schematic view is shown in Figure 2B. This set represents four cells. It can be noted that this module is symmetrical, so only one of the halves will be described, and everything said for this one will be valid for the other. Both halves of the intermediate module share two columns and a bundle of tubes with the input module or a previous intermediate module.

 The output module is also defined as the set of columns and beams, whose top view is shown in Figure 2C. This set represents only one cell. This module shares three columns and two tube bundles with the intermediate module immediately preceding it or with the input module in the absence of intermediate modules. In addition, its last column, which is supplied with culture medium by the other two columns and is not shared, connects to other equipment, external to the photobioreactor, in order to continue the cultivation cycle.

 Complementary system is defined as the tank, filter, riser, cylinder and separator assembly, as well as the pipes and connections that connect them.

The photobioreactor shown in Figure 3 (301, 301.1, 302, 302.1, 303, 303.1, 304, 304.1, 305, 305.1 and 306) is being shown as a side section (with overlapping columns). In addition, this photobioreactor may have a number of cells or modules in series ranging from one to the maximum allowed, given the available space for culture; Therefore, the representation of six cells or modules in series as in the figure above has as its objective the visualization of the project, not being a limiting factor to it. The beams may have a number of tubes ranging from one to the maximum allowed by the available space and the maximum column height (determined by one of ordinary skill in the art for ease of equipment maintenance). The tubes that make up this beam can have a straight circular section for ease of purchase and handling. The photobioreactor can be defined as a series and / or parallel association of the above described modules or single cultured cells. The reactor may have various cell arrangements and / or modules, with square and corridor arrangements being preferred.

In the squared arrangement, shown in Figure 4, "n ² " cells are arranged to form a square whose side contains "n" cells, where "n" is a number that can vary from one to the maximum allowed by the space available for. the cultivation. In this arrangement, the middle entry column is one of the columns at the vertices of the square. In this arrangement, the available space is well used and all the paths that the cultivation can go through the tubes have the same length, being one of its main qualities. Thus, a person skilled in the art can stipulate the tube diameters so that the residence time of the culture in the photobioreactor is constant and the path taken by this fraction of the medium is irrelevant in this determination. Another advantage of this arrangement is that the heights of liquid in the reactor columns can also be determined, and columns in which the pressure is equal (pressure lines) can be defined; preferably, these lines could be parallel to the diagonal that does not connect the input and output columns.

In the corridor arrangement, shown in Figure 5A and Figure 5B, the cells are arranged in modules (input, intermediate and output) and these, in series, form the nomenclature corridor. One of the advantages of this arrangement is that when all reactor tubes have the same diameter and are of the same material, all possible paths for cultivation to travel have the same length. As a result, all tubes have the same fluid flow, so the residence time in the reactor is independent of the path taken by the fluid fraction. Moreover, in this arrangement there is the existence of pressure lines; they are defined by joining two equidistant extreme columns of the input column. In Figure 5B, a representation of the aisle storage with the modules separated from each other, it is shown that this arrangement consists of the serial storage of an input module, "n" intermediate modules and an output module. This number "n" is determined, once again, by the availability of space for cultivation and may vary from zero to the maximum possible in the given space.

 For optimal use of available space, several aisles such as those described above can be associated in parallel so that the input modules of all aisles are on the same pressure lines as the output modules. In addition, the extreme columns of two adjacent corridors may or may not be shared by them. Additionally, there can be from several complementary systems (one for each corridor) to just one (supplying the entire photobioreactor network), as well as any other value within that range. The cells may also have a longer or wider diamond shape, depending on the length and width of the space available for cultivation and the interest in having more or fewer modules in the photobioreactor.

The arrangement of the cell as a quadrilateral is preferred in a photobioreactor, however, several other shapes are possible, such as circular, triangular, pentagonal, hexagonal, among others. The choice by the quadrilateral occurs because this form would facilitate obtaining and reduce the cost to manufacture. In addition, the provisions set out in this document are favored by the quadrangular cell.

 All considerations regarding the cells made above apply to the shape of the straight section of the column.

 Another possible arrangement is the single cell photobioreactor. This arrangement would be disadvantaged by the large use of space with lower productivity, but favored by its simplicity and lower relative cost.

In all arrangements, the tubes and columns that are connected by them in each cell must be transparent (for light, sunlight or artificial), rigid, withstand 1 bar pressure and temperatures from 5 ° C to 42 ° C. C, have high resistance to the sun and weather, do not suffer corrosion by saline water and ions that could be used as nutrients of microorganisms of interest and are not toxic to the microbial population or susceptible to wear due to contact with it. In addition, they must have zero or low roughness, do not allow microorganisms to adhere, be light and easy to handle, do not have excessive coefficient of thermal expansion, are not prohibitive for large-scale use, do not absorb infrared or red band radiation or ultraviolet radiation. In view of these considerations, the material composing such equipment may be polymeric, preferably polycarbonates, or glass, preferably borosilicate glass. Additionally, their diameters and widths cannot be excessive to avoid (or diminish) the shading effect of the culture by the high cellular concentration of the medium. The photobioreactor can operate with both direct and artificial sunlight. This factor can be adjusted according to the climatic characteristics of the implantation site. In the case of artificial lighting, it should preferably be made uniformly with respect to the tube bundles of the cell. To increase crop exposure to lighting (both solar and artificial), the photobioreactor columns can be tilted to the ground.

 The temperature control of the photobioreactor must also be made according to the climatic conditions of the project site and the favorable conditions for the growth and production of the desired byproducts of the species of interest. When the project is implemented under extreme weather conditions, indoor cultivation with temperature control may be recommended, either under sunlight or artificial light.

 Many other cell forms and photobioreactor arrangements are possible, and the foregoing are purely preferred herein and should not be construed as limiting thereof.

 The second object of the invention relates to a kit composed of a photobioreactor and the complementary system comprising sequentially forming a cycle, a culture medium storage tank, a biomass filter, a riser, storage tanks. gases needed for crop growth and an excess gas separator.

Figure 3 shows a simple schematic representation of the equipment involved in the cultivation process of photosynthetic organisms. The present invention is composed of a column photobioreactor (301, 301.1, 302, 302.1, 303, 303.1, 304, 304.1, 305, 305.1 and 306), one tank

(307), a biomass filter of photosynthetic organisms

(308), a riser and gas storage tanks required for crop growth (309.1, 309.2, 309.3 and 309.4) and an excess gas separator (310).

 Initially, the equipment is supplied with a culture medium with a certain concentration of cells and the necessary nutrients. In the photobioreactor, this medium comes into contact with a light source (natural or artificial). This illumination is necessary for the growth of culture, as the organisms of interest are photosynthetic. Most of the time, the medium is in the photobioreactor, due to its larger volume and the constant circulation rate of the system. This is because it is in the reactor that the culture has contact with lighting and can grow by reproducing its cells. Depending on the species of interest, the amount of nutrients, the available lighting, the temperature, the pH and the time between sunrise and sunset (in the case of natural lighting), a person skilled in the art may stipulate the time. of residence of the cells in the photobioreactor and, consequently, the desired flow of the system. It is interesting that this flow rate is not high, so that the medium velocity in the tubes does not cause stress to the cultivation due to the friction with the photobioreactor walls.

When leaving the photobioreactor, the culture goes to a storage tank (307), in which the culture temperature, pH, nutrient concentrations, among other process variables can be measured. This tank, which may or may not be shaken, also serves to add nutrients necessary for the perpetuation of the crop, such as vitamins, salts and metals. Preferably, the existence of such a tank at a height close to the photobioreactor assists in the return of the crop to the reactor after the end of the circuit to be traversed by its hydrodynamic head.

 Next, the cultivation goes to a filter (308) which will remove part of the biomass present in the medium. The removal of part of the biomass aims to maintain the functioning of the cycle without excess shading, derived from the high cell concentrations in the photobioreactor, in addition to allowing the development of young and more productive cells. Biomass taken from the system can have diverse applications, such as use in cosmetics and medicines, as a human or animal nutritional source and in the production of biofuels. In the process in question, not all the culture medium passes through the filter: this only happens with part of it, so that a minimum cell concentration is always maintained in the photobioreactor input column. The determination of the fraction of medium to be filtered will occur by analyzing the growth of the species of interest during residence in the photobioreactor under the existing conditions, so that the stipulated target of minimum initial concentration of residence in the reactor is met. The fraction of the medium that does not pass the filter is separated and followed by a bypass.

After this filtering, cultivation goes up a column, partly aided by the riser (309.1, 309.2, 309.3 and 309.4). The number of storage tanks may vary according to the needs of the microorganism of interest, not necessarily equal to four, as shown in Figure 3. A first function of the riser is to assist in raising the culture medium to the top. input column of the photobioreactor input module. Another function is the renewal of carbon dioxide and sulfur and nitrogen oxides (N0 _X and SO _x, respectively) of the medium. The gas mixture used for this process can be manipulated in order to perform photosynthesis and to provide the nutritional requirements of the culture medium organisms. In addition, the riser has advantages over the hydraulic pump as it offers less stress to the fluid, reducing the risk of cell disruption and consequent loss of reproductive capacity of the culture medium. The riser can function both continuously and discontinuously, depending on the choice of desired fluid flow rate in the process and the desired cellular reproduction rate.

 After rising from the riser, the fluid passes to a gas separator (310). In this separator, the fluid is kept for a time under reasonably stable conditions, with or without agitation, so that it can separate from excess gas, whether solubilized or not. This step aims to prevent the inhibition of photosynthetic growth of organisms by excess oxygen gas and other gases in the medium. In addition, it serves as a preparation stage for fluid entry into the photobioreactor. Purged gases at this stage can be stored in a tank and treated for release into the environment or recycled to the process.

 Finally, the third object of the invention concerns the use of the microorganism cultivation process kit, biomass and sequestration and the use of polluting gases as a nutritional source for photosynthetic microorganisms.

The preparation of the culture medium and the necessary nutrients, as well as the concentration of cells Required for system startup are common knowledge to a person skilled in the art and vary according to the type of interest.

 The process of obtaining biomass may have as its objective the production of biofuels through the cultivation of photosynthetic microorganisms.

 Finally, the sequestration of polluting gases, whether from burning fuels (fossil or renewable) or not, serves as a source of nutrients for the growth of photosynthetic microorganisms.

 In addition, the kit of the present invention can promote the sequestration and use of polluting gases and the obtaining of biomass for biofuel production simultaneously.

Claims

 PHOTOBIORREATOR AND KIT FOR CROPPING OF PHOTOSYNTHETIC MICROORGANISMS, OBTAINING BIOMASS, SEQUESTRESS AND USE OF POLLUTANT GASES AS A NUTRITIONAL SOURCE OF PHOTOSYNTHETIC MICROORGANISMS. 1 - Photobioreactor characterized by being operable under natural or artificial lighting and comprising one or more cells, having columns as vertices, these columns being interconnected by tube bundles, the cells being arranged, in modular or not, two adjacent cells sharing one or more columns and one or more tube bundles, comprising a column called an input column, into which the culture medium flow occurs, a number to be defined of intermediate columns whose input and output flows are internal to the photobioreactor, and a column called the exit column, in which the outflow of the medium culture occurs. Photobioreactor according to Claim 1, characterized in that the component columns of each cell are arranged as at least one of the circular, triangular, quadrangular, pentagonal and hexagonal shapes.  Photobioreactor according to Claim 2, characterized in that the component columns of each cell are preferably arranged as the vertices of a quadrilateral. Photobioreactor according to Claim 3, characterized in that the columns of each cell are preferably arranged as the vertices of a square. Photobioreactor according to any one of claims 1 to 4, characterized in that the interconnection between the columns and the tube bundles forms one or more polygonal or ellipsoidal patterns. Photobioreactor according to any one of claims 3 to 5, characterized by the arrangement of the cells forming a square with ^¾ n 'cells on each side, containing' 4 ^η -4 'outer cells, which are cells that do not share by least one of its tube bundles with another cell, and n-2) ² 'internal cells, which are cells that share all their tube bundles with other cells, being n greater than 1.  Photobioreactor according to any one of claims 1 to 5, characterized in that it contains at least one cell, preferably this cell being square. Photobioreactor according to any one of claims 3 to 5, characterized in that the cells are arranged in a series or parallel arranged corridors, each comprising an input module, which comprises three cells, one of which receives the flow of cells. cultivation of equipment external to the photobioreactor and the other two are supplied from the culture medium by the first cell, with which they share two columns and a bundle of tubes each, 'η' intermediate modules, which comprise four cells divided into two units of two adjacent cells each, in which their two cells share two columns and a tube bundle and share two columns and a tube bundle with the input module or a previous intermediate module, and the units share each other a column, where n is greater than or equal to zero, and an output module, which comprises a cell and shares 3 columns and two tube bundles with the anterior intermediate module or the input module in case there are no intermediate modules, the non-shared column being the photobioreactor output column.  Photobioreactor according to claim 8, characterized in that the association between the corridors is made in parallel.  Photobioreactor according to Claim 8, characterized in that the association between the corridors is made in parallel and in series.  Photobioreactor according to Claim 8, characterized in that it contains at least one corridor.  Photobioreactor according to any one of claims 1 to 11, characterized in that the straight section of the tube bundles is circular.  Photobioreactor according to any one of claims 1 to 12, characterized in that the straight section of the columns is circular. Photobioreactor according to any one of claims 1 to 12, characterized in that the straight section of the columns is quadrilateral.  Photobioreactor according to any one of claims 1 to 14, characterized in that it consists of borosilicate glass.  Photobioreactor according to any one of claims 1 to 14, characterized in that it consists of polymeric materials, preferably polycarbonate. Kit characterized in that it contains the photobioreactor as defined in claims 1 to 16 and a complementary system which comprises sequentially forming a culture medium storage tank, a filter biomass, a riser, gas storage tanks needed for crop growth and an excess gas separator.  Kit according to Claim 17, characterized in that the biomass filter contains a bypass and partially removes the microbial population.  Kit according to claims 17 and 18, characterized in that the riser introduces gases necessary for population growth, which are preferably at least one of the substances between carbon dioxide, sulfur oxide and nitrogen oxide.  Kit according to Claim 19, characterized in that the riser is capable of optionally introducing atmospheric air.  Kit according to Claim 19, characterized in that the riser is capable of optionally introducing carbon dioxide.  22 - Use of the kit characterized by promoting the cultivation of microorganisms, the obtaining of biomass and the sequestration and use of polluting gases.  Use of the kit according to claim 22, characterized in that it promotes biomass production for biofuels production by cultivating photosynthetic microorganisms.  Use of the kit according to claim 22, characterized by promoting the sequestration and use of polluting gases as a nutritional source of photosynthetic microorganisms. Use of the kit according to claim 24, characterized in that the sequestered gases are derived from the burning of fuels or not. Use of the kit according to claim 25, characterized in that. the fact that the sequestered gases come from burning fossil or renewable fuels. Use of the kit according to claims 22 to 26, characterized by promoting the sequestration and use of polluting gases and obtaining biomass for the production of biofuels simultaneously.