WO2020084413A1

WO2020084413A1 - Frozen biomass extraction

Info

Publication number: WO2020084413A1
Application number: PCT/IB2019/058883
Authority: WO
Inventors: Steven Splinter; Tomasz Popek; Harmandeep KAUR; Anna BAKOWSKA-BARCZAK
Original assignee: Radient Technologies Innovations Inc.
Priority date: 2018-10-23
Filing date: 2019-10-17
Publication date: 2020-04-30

Abstract

Systems and methods of extracting compounds from a frozen biomass are disclosed. The biomass is frozen upon harvesting or soon after harvesting. The frozen biomass will be placed into an extraction and decarboxylation system that thaws the biomass via microwave energy that then extracts cannabinoids from the biomass.

Description

FROZEN BIOMASS EXTRACTION

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present patent application claims the priority benefit of U.S. provisional patent application 62/749,569 filed Odober 23, 2018, the disclosure of which is incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field Of The Disclosure

[0002] The present disclosure is generally related to a system and method of extracting desired compounds from frozen biomass and more specifically related to freezing cannabis biomass prior to a microwave assisted extraction process.

2. Description Of The Related Art

[0003] Cannabis is a genus belonging to the family of Cannabaceae. There are three main spedes of Cannabis: Cannabis sativa, Cannabis indica, and Cannabis ruderalis. The three main species, Cannabis sativa, Cannabis indica, and Cannabis ruderalis, may also be treated as subspecies of the single spedes Cannabis sativa. The Cannabis genus is indigenous to central Asia and the Indian subcontinent. The term "cannabis" or "cannabis biomass" encompasses the three main spedes and variants thereof, including subspecies sativa, indica and ruderalis of the Cannabis sativa, and varieties characterized by chemical composition called cannabis cultivars and cannabis chemovars, which naturally contain different amounts of the individual cannabinoids, and also plants which are the result of genetic crosses. The term "cannabis biomass" is to be interpreted accordingly as encompassing plant material derived from one or more cannabis plants. [0004] Cannabis has a long history of being used for therapeutic and recreational purposes. The importance of cannabis in therapeutics is emphasized by the ever-increasing number of research publication related to the new use cases for cannabis. The cannabis plant is used for various medical purposes, such as herbal medicine used to treat intoxication, wasting syndrome, neurological symptoms including muscle spasticity, pain, nausea, vomiting, anorexia, and other symptoms commonly suffered by AIDS, chemotherapy, and glaucoma patients.

Administration of cannabis may be performed via smoking, vaping, oral ingestion, sublingual, and topical application.

[0005] Cannabis is becoming increasingly legal at the state level in the Chambered States, for either medical or recreational use. Each of these states has had to wrestle with the question of how to ensure the safety of a new product that is not covered under any existing safety guidelines. FDA, the USD A, or by other federal agencies usually regulate and provide support for safety testing in other agricultural industries. However, none of these federal agencies been able to assist the states in the cannabis industry. The few states that have produced safety testing guidelines for Cannabis were forced to develop them from scratch, without the regulatory and scientific support that federal agencies typically provide. In the absence of federal guidance, regulators in each state have turned to different sources for information, and some states have produced a unique set of rules and regulations. Many of these state safety guidelines are in outright conflict with other state guidelines. Some of the state guidelines are largely not grounded on scientific research.

[0006] The question of microbiological safety has been raised in order to promote the adoption of regulatory guidelines for the cannabis industry that are rational, consistent, and safe. Many factors encompass the issue of microbiology safety of cannabis and cannabis extracts including plant microbiology, medical microbiology, and safety-testing of agricultural and food products.

[0007] In addition to safety, subjective quality of cannabis biomass and extracts is becoming an increasingly important factor for consumers to consider. Many of the subjective qualities of cannabis ( e.g ., taste, aroma, look, and feel) are related to the molecular composition of the biomass. For example, aroma is produced primarily by aromatic terpenes produced as components of the resin secreted by glandular trichomes on the surface of the calyxes and subtending leaflets. When a floral cluster is squeezed, the resinous heads of glandular trichomes rupture and the aromatic terpenes are exposed to the air. There is often a large difference between the aroma of fresh and dry floral clusters due to the polymerization of many of the smaller molecules of aromatic terpenes to form different aromatic and nonaromatic terpene polymers. These happen as cannabis resins age and mature during the growth of the plant and while curing after harvest. Additional aromas may interfere with the primary terpenoid components, such as ammonia gas and other gaseous products given off by the curing, fermentation or spoilage of the tissue, non-resin portion of the floral clusters. A combination of at least twenty aromatic terpenes, 103 are known to occur in cannabis, and other aromatic compounds control the aroma of each plant. The production of each aromatic compound may be influenced by many genes; therefore, many strains of cannabis have been bred for aroma. Each strain, however, has several characteristic aromas that are occasionally transmitted to hybrid offspring to resemble one or both parents in aroma.

[0008] Cannabis biomass spoilage may not only affect the microbiological safety of the cannabis, but additionally the subjective qualities of the cannabis biomass and derivative products produced from cannabis biomass. Although techniques for drying and curing cannabis have become a standard practice for cannabis producers, such pre-processing of the material gives less control of the biomass to downstream processes, such as the extraction process. In these cases, the extraction would be subject to the drying and curing process of the grower of the cannabis, which would potentially create inefficiencies or contamination.

Retaining robust controls are essential to maintaining an efficient and pristine cannabis extraction process. Therefore, there exists a need to preserve the cannabis at the moment it is harvested and transport the cannabis in its preserved state to the extractor of the cannabis. Furthermore, starting the extraction and decarboxylation method with a frozen biomass eliminates the need for a drying step. This will help prevent microbial contamination.

[0009] For the purposes of the present invention, cannabis biomass and associated extraction of cannabinoids and other components of the cannabis biomass is understood as a general process for biomass handling and extraction of compounds and is not limited to only cannabis extraction, but extraction of any biomass and any related compound.

BRIEF DESCRIPTIONS OF THE DRAWINGS

[0010] FIG. 1 is a block diagram illustrating an exemplary system for extracting compounds from a frozen biomass.

[0011] FIG. 2 is a flowchart illustrating an exemplary method for extracting compounds from a frozen biomass.

[0012] FIG. 3 is a block diagram illustrating an exemplary continuous flow microwave extractor.

[0013] FIG.4 is a table illustrating exemplary amounts of compound content for various samples during an exemplary extraction process.

DETAILED DESCRIPTION

[0014] Systems and methods of extracting compounds from a frozen biomass are provided. FIG. 1 is a block diagram illustrating an exemplary system 100 for extracting compounds from a frozen biomass, and FIG. 2 is a flow chart illustrating an exemplary method 200 for extracting compounds from a frozen biomass. One skilled in the art will appreciate that, for this and other processes and methods disclosed herein, the functions performed in the processes and methods may be implemented in differing order. Furthermore, the outlined steps and operations are only provided as examples, and some of the steps and operations may be optional, combined into fewer steps and operations, or expanded into additional steps and operations without detracting from the essence of the disclosed embodiments.

[0015] First, a frozen biomass is provided and stored in the frozen biomass chamber 102 at step 202. The biomass may be frozen at the point of harvest or shortly after the plant is harvested. The frozen biomass chamber 102 is provided for storage of the frozen cannabis biomass in the form of frozen, non-decarboxylated flowers at a freezing temperature ( e.g . all or substantially all of the water in the biomass is in a solid phase). The frozen biomass contains or has the potential to contain the target compounds for extraction at the same levels as were present at the point of harvest or freezing.

[0016] To test for the compounds in the biomass, the biomass is sampled and analyzed at the sampling chamber 120 at step 204. The raw biomass may be sampled and analyzed using various methods. In one embodiment, analysis of the cannabinoid content and the cannabinoid profile may be performed utilizing Ultra High Performance Liquid Chromatography coupled with Mass Spectrometry detection ("UHPLC-MS") In addition, biomass may be sampled and analyzed for the biomass terpene profile utilizing Gas Chromatography - Mass Spectrometry Detection ("GC-MS"). The sampling and analysis method reveals the cannabinoid profile: the cannabinoid content and profile for the starting biomass (e.g., total cannabinoids,

tetrahydrocannabinolic acid ("THCA") plus tetrahydrocannabinol ("THC"), total THC equivalents, cannabidiolic acid ("CBDA", cannabidiol ("CBD"), total CBD equivalents and relative proportions of various minor cannabinoids).

[0017] The biomass preparation chamber 104 prepares the frozen biomass ( e.g ., grinding) at step 206. In one embodiment, raw biomass may be subjected to decarboxylation by heating the biomass, where the heat-based decarboxylation may also result in thawing of the frozen flowers. In other embodiments, the biomass remains subject to freezing temperatures, as well as grinding, where the average particle size of the biomass may be approximately 3-6mm for ground biomass. The prepared biomass is then stored at the biomass storage chamber 106, which may likewise be maintained at freezing temperatures.

[0018] The biomass is then transferred to the slurry formation chamber 108, where solvent is added to the prepared biomass to form a slurry at step 208. A solvent storage chamber 110 may be used for storing the solvent prior to being combined with the prepared biomass in the slurry formation chamber 108. The amount of solvent used may be based on the observations on typical solvent volumes required to cover the ground, frozen biomass with solvent. The type and amount of solvent may also be affected by the use of different types of extraction system, as well as selected temperatures at which to maintain the slurry.

[0019] For example, the use of a full-scale continuous-flow microwave assisted processing ("MAP") extraction system and related slurry-pumping equipment may require less amounts of solvent. While conventional solvent-based extraction that is purely diffusion-driven and relies on concentration gradients may require more amounts of solvent. In one embodiment, the extraction using the MAP may use a solvent-to-biomass ratio of 10 L/kg. The frozen biomass may also affect the amount of microwave energy that is identified for application to the slurry (e.g., to reach target temperatures) during extraction.

[0020] The types of solvents used for extractions may include at least one of the series of solvent composition having different dielectric and solvent parameter properties. For example, solvents may include different alcohols (e.g., ethanol, isopropanol), alkanes (e.g., ethane, propane, butane, pentane), ketones (e.g., acetone, butanone), and mixtures of each, including mixtures with water. All of these solvents are considered to be safe and acceptable for production of cannabis extracts and derivative products. It is understood that certain solvents are likely to be preferable from a marketing standpoint ( e.g ., ethanol).

[0021] After the slurry has been formed, the slurry is transported into the extractor 112 at step 210. The extractor may be shaped like a tube. Transportation of the slurry within the extractor may be conducted by a system of mechanical conveyance (e.g., worm gear). The extractor may be a continuous chamber where all or a portion of this chamber may be transparent to a heat source located in the heating generator 114. For example the extractor 112 may be microwave transparent. While in the extractor 112, the slurry may be subjected to thermal processing from the heating generator 114. For example, the thermal process may be microwave heat. When the heating generator 114 provides heat to the biomass in the extractor 112, the frozen biomass will be thawed and its target compounds extracted into the solvent within the slurry.

[0022] Upon exiting the extractor 112, the extracted ("spent") biomass may be separated from the solvent and extract mixture at step 212 and transferred to the spent biomass storage chamber 118. The solvent and extract mixture is called the "miscella." The separation of the spent biomass from the miscella may be performed through various separation methods such as filtration, centrifuge, etc. The spent biomass may then be sampled and disposed of in step 214. The spent biomass may be sampled in the sampling chamber 120. The miscella may also be sampled in the sampling chamber 120. The remaining spent biomass may be disposed up via incineration or mixed with a deactivating agent (e.g., clay) in the disposal chamber 122.

[0023] Once the miscella has been transferred from the filtration and separation chamber 116 to the solvent recovery chamber 124, the solvent may then be removed from the miscella at step 216. Known separation techniques include evaporation or distillation. The solvent is recovered for use in another extraction and stored in the solvent storage chamber 110 until the next extraction.

[0024] After the solvent is removed from the miscella, the resulting de-solvenized extract is transferred to the formulation chamber 126. The de-solvenized extract may be sampled in the sampling chamber 120. [0025] The de-solvenized extract is then formulated into a final formulated extract and stored in the formulated extract chamber 128 at step 218. The final formulated extract may be formulated via various formulation methods. The final form may be a solid form of

cannabinoids or a standardized liquid form of cannabinoids. The extracted active compounds from the cannabis biomass include cannabinoids such as THC, THCA, cannabidiol ("CBD"), cannabidiol acid ("CBDA"), Cannabigerol ("CBG"), Cannabinol ("CBN"), etc. The final formulated extract may be sampled and analyzed in the sampling chamber 120 at step 220 to determine cannabinoid content and profile.

[0026] The function of the "continuous flow microwave" extractor will now be explained with reference to FIG. 3. FIG. 3 is a block diagram illustrating an exemplary continuous flow microwave extractor 300. FIG. 3 provides additional details of the system during the extraction step 210 as shown in FIG. 2. After the slurry is formed by combining the raw biomass with the solvent of choice at 302. The slurry then enters an extractor at 304. The extractor may contain a continuous flow chamber and is exposed to microwaves at 306 from an outside source of microwave at 312. The microwaves may have frequencies of between 300 MHz and 300 GHz. In a preferred embodiment the microwaves may have a frequency of 915 MHz. The power of the microwaves may be varied to achieve maximal extraction. The microwaves will heat the slurry and thaw the frozen biomass in the slurry. Upon exiting the extractor chamber, the desired compounds would have been extracted from the biomass and dissolved into the solvent miscella at step 308. After exiting the extractor, the biomass may be separated from the slurry through various separation operations, including filtration, centrifuge, or other downstream separation processes to remove the biomass at step 310. Additional microwave assisted process may be used for related uses, such as decarboxylation of any acidic cannabinoids.

[0027] The results of the sampling and analysis of the various items during the extraction process will now be explained with reference to FIG. 4. FIG. 4 is a table illustrating the exemplary amounts of the desired compound content for various samples during an exemplary extraction process. [0028] FIG. 4 displays the example content of the desired compounds that may be present in the raw biomass at the beginning of the extraction process, the miscella immediately after the extraction / biomass separation, the extract, and the spent biomass. In this example, the THCA is extracted from a cannabis biomass into the solvent ethanol. The term "miscella" refers to the solvent that contains the desired compound(s) after it has been separated from the biomass following the extraction process. In this example, the desired compound is THCA. The raw biomass contains 5.7% THCA by mass. The miscella contains 0.47% THCA. The extract contains 71% THCA. The spent biomass contains 0.55% THCA. In this example, 91% of the initial THCA content of the raw biomass is present in the extract, and 8% of the THC remains in the spent biomass.

Claims

CLAIMS WHAT IS CLAIMED IS:

1. A method for extracting compounds from a frozen biomass, the method comprising:

maintaining a frozen biomass at a freezing temperature within a frozen biomass chamber;

mixing the frozen biomass with a solvent to form a slurry;

extracting one or more compounds by exposing the slurry to heat in a continuous flow, wherein the heat thaws the frozen biomass and results in the extraction of the compounds from the thawed biomass into the heated slurry; and

separating the spent biomass and the solvent from the extracted compounds.

2. The method of claim 1, further comprising freezing a harvested biomass at a time of harvest to obtain the frozen biomass.

3. The method of claim 1, further comprising freezing the harvested biomass at a specified time at which the one or more compounds within the harvested biomass meet a specified level.

4. The method of claim 3, further comprising sampling the frozen biomass to confirm that the one or more compounds within the frozen biomass meet the specified level.

5. The method of claim 1, further comprising grinding the frozen biomass prior to mixing with the solvent, and storing the ground biomass at a freezing temperature within a biomass storage chamber.

6. The method of claim 1, further comprising decarboxylating the frozen biomass by heating the frozen biomass for a period of time selected for thawing and decarboxylating the frozen biomass.

7. The method of claim 1, wherein the solvent includes at least one of alcohols, alkanes, ketones, and water.

8. The method of claim 1, wherein the slurry is mixed at a ratio of 10 L solvent per kg of frozen biomass.

9. The method of claim 1, wherein an amount of solvent selected to mix with the frozen biomass is based on a desired flow rate of the continuous flow of the slurry.

10. The method of claim 1, wherein exposing the slurry to heat includes generating an amount of microwave energy selected based on the properties of the slurry and the desired temperature of the slurry.

11. An apparatus for extracting compounds from a frozen biomass, the apparatus comprising: a frozen biomass chamber that maintains a frozen biomass at a freezing temperature; a slurry formation chamber that mixes the frozen biomass with a solvent to form a slurry; an extraction chamber that extracts one or more compounds by exposing the slurry to heat in a continuous flow, wherein the heat thaws the frozen biomass and results in the extraction of the compounds from the thawed biomass into the heated slurry; and

a separation chamber that separates the spent biomass and the solvent from the extracted compounds.

12. The apparatus of claim 11, further comprising a freezer that freezes a harvested biomass at a time of harvest to obtain the frozen biomass.

13. The apparatus of claim 11, further comprising a freezer that freezes the harvested biomass at a specified time at which the one or more compounds within the harvested biomass meet a specified level.

14. The apparatus of claim 13, further comprising a sampling chamber that samples the frozen biomass to confirm that the one or more compounds within the frozen biomass meet the specified level.

15. The apparatus of claim 11, further comprising a preparation chamber that grinds the frozen biomass prior to mixing with the solvent, and a biomass storage chamber that stores the ground biomass at a freezing temperature.

16. The apparatus of claim 11, further comprising a biomass preparation chamber that decarboxylates the frozen biomass by heating the frozen biomass for a period of time selected for thawing and decarboxylating the frozen biomass.

17. The apparatus of claim 11, wherein the solvent include at least one of alcohols, alkanes, ketones, and water.

18. The apparatus of claim 11, wherein the slurry is mixed at a ratio of 10 L solvent per kg of frozen biomass.

19. The apparatus of claim 11, wherein an amount of solvent selected to mix with the frozen biomass is based on a desired flow rate of the continuous flow of the slurry.

20. The apparatus of claim 11, further comprising a microwave generator that provides the heat to which the slurry is exposed, the microwave generator generating an amount of microwave energy selected based on the properties of the slurry and the desired temperature of the slurry .