BACKGROUND

[0001] The invention generally relates to the field of microorganism biomass processing, and, more particularly to a method of extending the shelf life of a microalgae biomass.

[0002] Microalgae or microphytes are microscopic organisms commonly found in freshwater and marine systems. Microalgae are a unicellular species that may exist individually, in chains, or in groups. Some estimates suggest that microalgae are responsible for almost 50% of the global carbon fixation. Currently many different species of microalgae are available worldwide. Microalgae can be cultured as pure strains for intensive systems.

[0003] Microalgae are rich in proteins, carbohydrates and lipids; and are the source of many beneficial products in a wide range of commercial applications. These applications may include: (i) uses to enhance the nutritional value of food and animal feed; (ii) aquaculture; and (iii) cosmetics. Moreover, microalgae are a source of highly valuable molecules.

[0004] Known methods of preserving microalgae may include the following steps: (i) microalgae is harvested; (ii) the harvested microalgae is then rinsed; (iii) the rinsed microalgae is then pressed manually or mechanically; and (iv) the pressed microalgae is then preserved.

[0005] Drying reduces the water content of the microalgae to below 5%, aiding in the preservation of the microalgae. Currently known drying processes include: oven drying, spray drying, or freeze drying. The aim of these drying processes is to preserve the microalgae in a dehydrated and concentrated form. Dehydrated microalgae powder may have a non- refrigerated shelf life of 1 -3 years. However, the dehydrated microalgae biomass is not a fresh product and has lost some nutritional properties. Therefore, using the known processing method, it is very difficult to use the microalgae biomass as an ingredient in processed foods. Furthermore, the microalgae may no longer be used to start new microalgae cultures since the fully dehydrated microalgae cells are ruptured and dead.

[0006] One particular microorganism of interest is the Arthrospira genus, commonly referred to as Spirulina. While spirulina is technically a cyanobacteria, it is commonly referred to as a blue-green microalgae, and for the purposes herein we will consider it as such. The biomass of spirulina is commonly consumed by humans and animals. There are many species of spirulina including: Arthrospira platensis and Arthrospira maxima. Spirulina is a complete protein source, containing all essential amino acids, while also being rich in iron and vitamin A.

[0007] In the known marketplace, the microalgae biomass is not commonly available in a fresh form because its shelf life is normally less than one week. After a few days, the fresh microalgae biomass may become expired. As discussed, preservation of a microalgae biomass is commonly done by dehydration. As a result, the microalgae biomass no longer remains a fresh product and loses some nutritional properties. Also, the known drying processes can stress or break the microalgae cells; resulting in poor perishability. Therefore, there is a need for a cost effective and different method for increasing the shelf life of the fresh microalgae.

SUMMARY OF THE INVENTION

[0008] Certain embodiments commensurate in scope with the originally claimed invention are summarized below. These embodiments are not intended to limit the scope of the claimed invention, but rather these embodiments are intended only to provide a brief summary of possible forms of the invention. Indeed, the invention may encompass a variety of forms that may be similar to or different from the embodiments set forth below.

[0009] Embodiments of the present invention provide methods for extending the shelf life of a refrigerated microalgae biomass. These methods may include the following steps. Removing a microalgae biomass using a first filter; here, the water content of the microalgae biomass is greater than 80%. Then, rinsing a portion of the microalgae biomass in a solution to substantially remove at least one undesired substance from the microalgae biomass. Then, refiltering the microalgae biomass using a second filter to remove excess fluid, here the refiltering decreases the water content of the microalgae biomass. Lastly, drying the microalgae biomass using a water removal device, here the water content level in the microalgae biomass is reduced to a First Level.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] These and other features, aspects, and advantages of the present invention may become better understood when the following detailed description is read with reference to the accompanying figures (FIGS) in which like characters represent like elements/steps throughout the FIGS.

[0011] FIG. 1 is a simplified flow diagram illustrating a method to extend the shelf life of refrigerated microalgae biomass according to an embodiment of the present invention. [0012] FIG. 2 is a simplified flow diagram illustrating a method to extend the shelf life of spirulina biomass according to an embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS [0013] One or more specific embodiments of the present invention will be described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in an engineering or design project, numerous implementation-specific decisions are made to achieve the specific goals, such as compliance with system-related and/or business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

[0014] Detailed example embodiments are disclosed herein. However, specific structural and functional details disclosed herein are merely representative for purposes of describing example embodiments. Embodiments of the present invention may, however, be embodied in many alternate forms, and should not be construed as limited to only the embodiments set forth herein.

[0015] Accordingly, while example embodiments are capable of various modifications and alternative forms, embodiments thereof are illustrated by way of example in the figures and will herein be described in detail. It should be understood, however, that there is no intent to limit example embodiments to the particular forms disclosed, but to the contrary, example embodiments are to cover all modifications, equivalents, and alternatives falling within the scope of the present invention.

[0016] The terminology used herein is for describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises", "comprising", "includes" and/or "including", when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

[0017] Although the terms first, second, primary, secondary, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, but not limiting to, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term "and/or" includes any, and all, combinations of one or more of the associated listed items.

[0018] Certain terminology may be used herein for the convenience of the reader only and is not to be taken as a limitation on the scope of the invention. For example, words such as“upper”,“lower”,“left”,“right”,“front” ,“rear”,“top”,“bottom”,“horizontal”,“verti cal”, “upstream”,“downstream”,“fore”,“aft”, and the like; merely describe the configuration shown in the FIGS. Indeed, the element or elements of an embodiment of the present invention may be oriented in any direction and the terminology, therefore, should be understood as encompassing such variations unless specified otherwise.

[0019] Embodiments of the present invention provide a method for extending the shelf life of a refrigerated microalgae biomass. Although an embodiment of the present invention will include spirulina biomass; the reader should understand that this is a non-limiting example only. The present invention may be adapted for use with other types of microalgae biomass.

[0020] Referring now to the FIGS, where the various numbers represent like components throughout the several views, FIG. 1 is a simplified flow diagram illustrating a method to extend the shelf life of refrigerated microalgae biomass according to an

embodiment of the present invention.

[0021] FIG. 1 is a flow diagram 100 illustrating a method to extend the shelf life of a refrigerated microalgae biomass according to an embodiment herein. In step 110, the microalgae biomass may be removed from a pond, tank, or other container type structure, using a first filter. The first filter may be of a size and type suitable to perform the method 100. A portion of the filter may comprise a meshing surface that allows for separating the microalgae biomass from the fluid in which it resides. At this stage of the process, the water content in the microalgae biomass may be greater than 80%.

[0022] In step 120, the method 100 may determine whether the strain of the microalgae biomass is of a saltwater type or of a fresh water type. As known in the art, methods of processing saltwater types generally vary from methods of processing freshwater types. Embodiments of the present invention may be applied to both saltwater and freshwater types, as is described below. If the microalgae biomass is a saltwater type, then the method 100 may proceed to step 130. If the microalgae biomass is a freshwater type, then the method 100 may proceed to step 140.

[0023] In step 130, the saltwater type of microalgae biomass may be rinsed in a saline, or saline-type, solution. The salinity in the solution serves to reduce the likelihood of rupturing of the microalgae cells of the saltwater type. Whereas, simply rinsing the saltwater type with fresh water has not been shown to reduce the likelihood of rupturing of the microalgae cells. Another benefit of this rinsing step 130, is the removal of some or all of an undesired substance; such as, but not limited to, at least one residual fertilizer, of which the microalgae biomass may have been subjected. Another benefit of the rinsing step 130, may be a decrease in the perishability of the microalgae biomass. In an example embodiment, the saline solution may comprise a range of from about 1% to about 3% salinity.

[0024] In step 140, the freshwater type of microalgae biomass may be rinsed in a freshwater solution. This rinsing step 140 may removal of some or all of an undesired substance; such as, but not limited to, at least one residual fertilizer. Another benefit of the rinsing step 140, may be a decrease in the perishability of the microalgae biomass.

[0025] In step 150, the microalgae biomass may be refiltered using a second filter. This step 150 serves to remove some of the excess rinsing solution resulting from either step 130 or step 140. Here, the second filter may be of the same, or similar type, used in step 110.

[0026] In step 160, the microalgae biomass may be dried using a water removal device.

Here, the microalgae biomass may be deposited in the device. The device is designed to operate in a manner that does not apply excessive mechanical pressure or stress during drying. During this step 160, the water content level of the microalgae biomass slurry may be reduced to a range of a desired range. In an embodiment of the present invention where the microalgae biomass is a spirulina biomass, the water content level may be reduced to a range of from about 70% to about 80%. In an example embodiment, the water removal device may have the form of a centrifuge machine, or the like. [0027] In step 170, the method 100 may determine whether the product shelf-life requirement is met. Here, embodiments of the present invention provide the user with the flexibility of processing a microalgae biomass in a manner to meet the shelf-life requirements of the customer. Some customers may desire a shelf-life of multiple weeks. Whereas other customers may desire a shelf-life of approximately a few months. If the product shelf-life requirement is up to a multiple of weeks, then the method 100 may proceed to step 190. Otherwise, if the product shelf-life requirement is approximately a few months, then the method 100 may proceed to step 180.

[0028] In step 180, the method 100 may dry the microalgae biomass to a second level. This process of drying to a second level may considerably extend the shelf-life from a few weeks to a few months. In an embodiment of the present invention, a plurality of ceramic beads may be used to promote the further drying of the microalgae biomass. Here, the ceramic beads may absorb and hold residual water from previous steps of the method 100. In an embodiment of the present invention, the ceramic beads may extend the shelf-life to a period from about three (3) to five (5) weeks; to about eight (8) to twelve (12) weeks.

[0029] In step 190, the method 100 may store the microalgae biomass in a refrigerated container. Here, a wide variety of containers may be used. This may include refrigerators or any other structure that may cool the microalgae biomass to the temperature range which will promote the desired shelf-life.

[0030] Referring now to FIG. 2, which is a simplified flow diagram illustrating a method to extend the shelf life of spirulina biomass, in accordance with a second

embodiment of the present invention. FIG. 2 may be representative of a preferred

embodiment, or a best mode, of implementing the present invention where the microalgae biomass is of a spirulina biomass type.

[0031] In step 210, the spirulina biomass may be removed from a pond, tank, or other container type structure using a first cloth filter. Here, a portion of the filter may include a cloth or cloth-like material which functions to separate the spirulina biomass from the fluid in which it resides. At this stage of the process, the water content in the spirulina biomass may be greater than 80%.

[0032] In step 220, the spirulina biomass may be rinsed in a saline, or saline-type, solution. This may reduce rupturing of the microalgae cells of the spirulina biomass. Additional benefits of rinsing the spirulina biomass in a saline solution were described in step 120 of FIG 1. In a preferred embodiment, the saline solution may comprise a range of up to

7.5% salinity.

[0033] In step 230, the microalgae biomass may be refiltered using a second cloth filter. This step 230 may remove excess water and salt resulting from step 220. Here, the second cloth filter may be of the same, or similar type, used in step 210.

[0034] In step 240, the spirulina biomass may be dried to a First Level using a centrifuge, or centrifuge like, device. Here, the spirulina biomass may be filled in a spinning bag that is secured inside of the centrifuge. The centrifuge may provide a cost-effective way to reduce the water content in spirulina biomass. The centrifuge may be operated in a manner that does not apply excessive mechanical pressure or stress. In an embodiment of the present invention, the centrifuge may operate in a range of from about 300 rpms to about 1000 rpms.

[0035] During step 240, the water content level of spirulina biomass slurry may be reduced to a First Level. In an embodiment of the present invention the First Level may be reduced to a range of from about 70% to about 80% water content. The reduced water content level may increase the shelf life of the spirulina biomass from about 1 to 5 days to about 3 to 5 weeks under a refrigerated condition.

[0036] In step 250, the method 200 may determine whether the product shelf-life requirement is met. Here, embodiments of the present invention provide the user with the flexibility of processing a spirulina biomass in a manner to meet the shelf-life requirements of the customer. Some customers may desire a shelf-life of multiple weeks. Whereas other customers may desire a shelf-life of approximately a few months. If the product shelf-life requirement is up to a multiple of weeks, then the method 200 may proceed to step 270. Otherwise, if the product shelf-life requirement is approximately a few months, then the method 200 may proceed to step 260.

[0037] In step 260, the method 200 may dry the microalgae biomass to a Second Level. This process of drying to a Second Level may considerably extend the shelf-life from a few weeks to a few months. In an embodiment of the present invention, a plurality of hydrophilic beads may be used to promote the further drying of the microalgae biomass. Here, the hydrophilic beads may absorb and hold residual saline solution from previous steps of the method 200. In an embodiment of the present invention, the hydrophilic beads may extend the shelf-life to a period from about three (3) to five (5) weeks; to about eight (8) to twelve (12) weeks, by reducing the water content to by up to 70%. In an embodiment of the present invention the hydrophilic beads may comprise zeolite ceramic beads, or the like.

[0038] In step 270, the method 200 may store the spirulina biomass in a refrigerated container. Here, a wide variety of containers may be used. This may include refrigerators or any other structure that may cool the spirulina biomass to the temperature range which will promote the desired shelf-life. [0039] Although specific embodiments have been illustrated and described herein, those of ordinary skill in the art appreciate that any arrangement, which is calculated to achieve the same purpose, may be substituted for the specific embodiments shown and that the invention has other applications in other environments. This application is intended to cover any adaptations or variations of the present invention. The following claims are in no way intended to limit the scope of the invention to the specific embodiments described herein.

As one of ordinary skill in the art will appreciate, the many varying features and

configurations described above in relation to the several embodiments may be further selectively applied to form other possible embodiments of the present invention. Those skilled in the art will further understand that all possible iterations of the present invention are not provided or discussed in detail, even though all combinations and possible

embodiments embraced by the several claims below or otherwise are intended to be part of the instant application. In addition, from the above description of several embodiments of the invention, those skilled in the art will perceive improvements, changes, and

modifications. Such improvements, changes, and modifications within the skill of the art are also intended to be covered by the appended claims. Further, it should be apparent that the foregoing relates only to the described embodiments of the present application and that numerous changes and modifications may be made herein without departing from the spirit and scope of the application as defined by the following claims and the equivalents thereof.

[0001] Embodiments of the present invention have the technical effect of extending the shelf life of a refrigerated microalgae biomass, by providing a method that comprises the steps of: removing a microalgae biomass using a first filter, wherein the water content of the microalgae biomass is greater than 80%; rinsing a portion of the microalgae biomass in a solution to substantially remove at least one undesired substance from the microalgae biomass; refiltering the microalgae biomass using a second filter to remove excess fluid, wherein the refiltering decreases the water content of the microalgae biomass; and drying the microalgae biomass using a water removal device, wherein the water content level in the microalgae biomass is reduced to a First Level. This method may further comprise the step of cooling the microalgae biomass in a manner that extends the shelf life of the microalgae biomass under a cooled condition. The method may further comprise the step of further reducing the water content of the microalgae biomass to a Second Level by using a plurality of hydrophilic beads, and wherein the step of reducing the water content level further extends the shelf life of the microalgae biomass under the cooled condition. The microalgae biomass of the present invention may comprise a spirulina type biomass. The step of rinsing the microalgae biomass in the saline solution is designed to decrease the perishability of the microalgae biomass.

[0002] Embodiments of the present invention may include a level of salinity in the saline solution comprises a range of up to 7.5% salinity. Furthermore, at least one of the filters used by the present invention may be of the cloth-type.

[0003] Furthermore, in embodiments of the present invention, the First Fevel may include a range of from about 70% to about 80% water content; and the Second Fevel may include a range of up to 70% water content. In embodiments of the present invention the hydrophilic beads may include a plurality of zeolite ceramic beads. For some embodiments of the present invention, the water removal device may include a centrifuge or centrifuge -like device. [0004] Some embodiments of the present invention may further comprise the steps of: determining whether the microalgae biomass is either a saltwater strain or a freshwater strain; if the microalgae biomass is a saltwater strain, then rinsing the microalgae biomass in a saline solution; or if the microalgae biomass is a freshwater strain, then rinsing the microalgae biomass in a freshwater solution.

[0005] Other embodiments of the present invention may provide a method for extending shelf life of a refrigerated microalgae biomass, wherein the method comprises of: removing a spirulina biomass using a first cloth filter from a container, wherein the water content of the spirulina biomass is greater than 80%; removing at least one fertilizer from the spirulina biomass by rinsing the spirulina biomass in a saline solution to considerably reduce rupturing of spirulina biomass cells; refiltering the spirulina biomass with a second filter to decrease the water content of the spirulina biomass; and drying the spirulina biomass using a centrifuge, wherein the water content level in the spirulina biomass is reduced to a First Level. Here, the method of claim may further comprise the step of cooling the spirulina biomass in a manner that extends a shelf life of the spirulina biomass in a cooled condition to between three (3) weeks to five (5) weeks. The method may also comprise the step of reducing the water content of the spirulina biomass to a Second Level with the aid of a plurality of hydrophilic beads to further extend the shelf life of the microalgae biomass under the cooled condition to between eight (8) weeks to twelve (12) weeks. Here, a level of salinity in the saline solution may include a range of up to 7.5% salinity; and the step of rinsing decreases the perishability of the microalgae biomass wherein the First Level may comprise a range of from about 70% to about 80% water content. Here, the method may further comprise drying the spirulina biomass until the water content is reduced to a Second Level; wherein the Second Level comprises a range of up to 70% water content. In embodiments of the present invention the centrifuge may operate in a range of from about 300 rpm to about 1000 rpm; and wherein the spirulina biomass is positioned with a spinning bag and integrated with the centrifuge.