Tag Archives: biochemistry

extractiongraphic

The Four Pillars of Cannabis Processing

By Christian Sweeney
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extractiongraphic

Cannabis extraction has been used as a broad term for what can best be described as cannabis processing. A well-thought-out cannabis process goes far beyond just extraction, largely overlapping with cultivation on the front-end and product development on the back-end1. With this in mind, four pillars emerge as crucial capabilities for developing a cannabis process: Cultivation, Extraction, Analytics and Biochemistry.

The purpose and value of each pillar on their own is clear, but it is only when combined that each pillar can be optimized to provide their full capacities in a well-designed process. As such, it is best to define the goals of each pillar alone, and then explain how they synergize with each other.

At the intersection of each pillar, specific technology platforms exist that can effectively drive an innovation and discovery cycle towards the development of ideal products.Cultivation is the foundation of any horticultural process, including cannabis production. Whether the goal be to convert pigments, flavors or bioactive compounds into a usable form, a natural process should only utilize what is provided by the raw material, in this case cannabis flower. That means cultivation offers a molecular feedstock for our process, and depending on our end goals there are many requirements we may consider. These requirements start as simply as mass yield. Various metrics that can be used here include mass yield per square foot or per light. Taken further, this yield may be expressed based not only on mass, but the cannabinoid content of the plants grown. This could give rise to a metric like CBD or THC yield per square foot and may be more representative of a successful grow. Furthermore, as scientists work to learn more about how individual cannabinoids and their combinations interact with the human body, cultivators will prioritize identifying cultivars that provide unique ratios of cannabinoids and other bioactive compounds consistently. Research into the synergistic effect of terpenes with cannabinoids suggests that terpene content should be another goal of cultivation2. Finally, and most importantly, it is crucial that cultivation provide clean and safe materials downstream. This means cannabis flower free of pesticides, microbial growth, heavy metals and other contaminants.

Extraction is best described as the conversion of target molecules in cannabis raw material to a usable form. Which molecules those are depends on the goals of your product. This ranges from an extract containing only a pure, isolated cannabinoid like CBD, to an extract containing more than 100 cannabinoids and terpenes in a predictable ratio. There are countless approaches to take in terms of equipment and process optimization in this space so it is paramount to identify which is the best fit for the end-product1. While each extraction process has unique pros and cons, the tunability of supercritical carbon dioxide provides a flexibility in extraction capabilities unlike any other method. This allows the operator to use a single extractor to create extracts that meet the needs of various product applications.

Analytics provide a feedback loop at every stage of cannabis production. Analytics may include gas chromatography methods for terpene content3 or liquid chromatography methods for cannabinoids 3, 4, 5. Analytical methods should be specific, precise and accurate. In an ideal world, they can identify the compounds and their concentrations in a cannabis product. Analytics are a pillar of their own due simply to the efforts required to ensure the quality and reliability of results provided as well as ongoing optimization of methods to provide more sensitive and useful results. That said, analytics are only truly harnessed when paired with the other three pillars.

extractiongraphic
Figure 1: When harnessed together the pillars of cannabis processing provide platforms of research and investigation that drive the development of world class products.

Biochemistry can be split into two primary focuses. Plant biochemistry focuses back towards cultivation and enables a cannabis scientist to understand the complicated pathways that give rise to unique ratios of bioactive molecules in the plant. Human biochemistry centers on how those bioactive molecules interact with the human endocannabinoid system, as well as how different routes of administration may affect the pharmacokinetic delivery of those active molecules.

Each of the pillars require technical expertise and resources to build, but once established they can be a source of constant innovation. Fig. 1 above shows how each of these pillars are connected. At the intersection of each pillar, specific technology platforms exist that can effectively drive an innovation and discovery cycle towards the development of ideal products.

For example, at the intersection of analytics and cultivation I can develop raw material specifications. This sorely needed quality measure could ensure consistencies in things like cannabinoid content and terpene profiles, more critically they can ensure that the raw material to be processed is free of contamination. Additionally, analytics can provide feedback as I adjust variables in my extraction process resulting in optimized methods. Without analytics I am forced to use very rudimentary methods, such as mass yield, to monitor my process. Mass alone tells me how much crude oil is extracted, but says nothing about the purity or efficiency of my extraction process. By applying plant biochemistry to my cultivation through the use of analytics I could start hunting for specific phenotypes within cultivars that provide elevated levels of specific cannabinoids like CBC or THCV. Taken further, technologies like tissue culturing could rapidly iterate this hunting process6. Certainly, one of the most compelling aspects of cannabinoid therapeutics is the ability to harness the unique polypharmacology of various cannabis cultivars where multiple bioactive compounds are acting on multiple targets7. To eschew the more traditional “silver bullet” pharmaceutical approach a firm understanding of both human and plant biochemistry tied directly to well characterized and consistently processed extracts is required. When all of these pillars are joined effectively we can fully characterize our unique cannabis raw material with targeted cannabinoid and terpene ratios, optimize an extraction process to ensure no loss of desirable bioactive compounds, compare our extracted product back to its source and ensure we are delivering a safe, consistent, “nature identical” extract to use in products with predictable efficacies.

Using these tools, we can confidently set about the task of processing safe, reliable and well characterized cannabis extracts for the development of world class products.

[1] Sweeney, C. “Goal-Oriented Extraction Processes.” Cannabis Science and Technology, vol 1, 2018, pp 54-57.

[2] Russo, E. B. “Taming THC: potential cannabis synergy and phytocannabinoid-terpenoid entourage effects.” British Journal of Pharmacology, vol. 163, no. 7, 2011, pp. 1344–1364.

[3] Giese, Matthew W., et al. “Method for the Analysis of Cannabinoids and Terpenes in Cannabis.” Journal of AOAC International, vol. 98, no. 6, 2015, pp. 1503–1522.

[4] Gul W., et al. “Determination of 11 Cannabinoids in Biomass and Extracts of Different Varieties of Cannabis Using high-Performance Liquid Chromatography.” Journal of AOAC International, vol. 98, 2015, pp. 1523-1528.

[5] Mudge, E. M., et al. “Leaner and Greener Analysis of Cannabinoids.” Analytical and Bioanalytical Chemistry, vol. 409, 2017, pp. 3153-3163.

[6] Biros, A. G., Jones, H. “Applications for Tissue Culture in Cannabis Growing: Part 1.” Cannabis Industry Journal, 13 Apr. 2017, www.cannabisindustryjournal.com/feature_article/applications-for-tissue-culture-in-cannabis-growing-part-1/.

[7] Brodie, James S., et al. “Polypharmacology Shakes Hands with Complex Aetiopathology.” Trends in Pharmacological Sciences, vol. 36, no. 12, 2015, pp. 802–821.

Understanding Dissolved Oxygen in Cannabis Cultivation

By Aaron G. Biros
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Oxygen plays an integral role in plant photosynthesis, respiration and transpiration. Photosynthesis requires water from the roots making its way up the plant via capillary action, which is where oxygen’s job comes in. For both water and nutrient uptake, oxygen levels at the root tips and hairs is a controlling input. A plant converts sugar from photosynthesis to ATP in the respiration process, where oxygen is delivered from the root system to the leaf and plays a direct role in the process.

Charlie Hayes has a degree in biochemistry and spent the past 17 years researching and designing water treatment processes to improve plant health. Hayes is a biochemist and owner of Advanced Treatment Technologies, a water treatment solutions provider. In a presentation at the CannaGrow conference, Hayes discussed the various benefits of dissolved oxygen throughout the cultivation process. We sat down with Hayes to learn about the science behind improving cannabis plant production via dissolved oxygen.

In transpiration, water evaporates from a plant’s leaves via the stomata and creates a ‘transpirational pull,’ drawing water, oxygen and nutrients from the soil or other growing medium. That process helps cool the plant down, changes osmotic pressure in cells and enables a flow of water and nutrients up from the root system, according to Hayes.

Charlie Hayes, biochemist and owner of Advanced Treatment Technologies

Roots in an oxygen-rich environment can absorb nutrients more effectively. “The metabolic energy required for nutrient uptake come from root respiration using oxygen,” says Hayes. “Using high levels of oxygen can ensure more root mass, more fine root hairs and healthy root tips.” A majority of water in the plant is taken up by the fine root hairs and requires a lot of energy, and thus oxygen, to produce new cells.

So what happens if you don’t have enough oxygen in your root system? Hayes says that can reduce water and nutrient uptake, reduce root and overall plant growth, induce wilting (even outside of heat stress) in heat stress and reduce the overall photosynthesis and glucose transfer capabilities of the plant. Lower levels of dissolved oxygen also significantly reduce transpiration in the plant. Another effect that oxygen-deprived root systems can have is the production of ethylene, which can cause cells to collapse and make them more susceptible to disease. He says if you are having issues with unhealthy root systems, increasing the oxygen levels around the root system can improve root health. “Oxygen starved root tips can lead to a calcium shortage in the shoot,” says Hayes. “That calcium shortage is a common issue with a lack of oxygen, but in an oxygen-deprived environment, anaerobic organisms can attack the root system, which could present bigger problems.”

So how much dissolved oxygen do you need in the root system and how do you achieve that desired level? Hayes says the first step is getting a dissolved oxygen meter and probe to measure your baseline. The typical dissolved oxygen probe can detect from 20 up to 50 ppm and up to 500% saturation. That is a critical first step and tool in understanding dissolved oxygen in the root system. Another important tool to have is an oxidation-reduction potential meter (ORP meter), which indicates the level of residual oxidizer left in the water.

Their treatment system includes check valves that are OSHA and fire code-compliant.

Citing research and experience from his previous work, he says that health and production improvements in cannabis plateau at the 40-45 parts-per-million (ppm) of dissolved oxygen in the root zone. But to achieve those levels, growers need to start with an even higher level of dissolved oxygen in a treatment system to deliver that 40-45 ppm to the roots. “Let’s say for example with 3 ppm of oxygen in the root tissue and 6ppm of oxygen in the surrounding soil or growing medium, higher concentrations outside of the tissue would help drive absorption for the root system membrane,” says Hayes.

Reaching that 40-45 ppm range can be difficult however and there are a couple methods of delivering dissolved oxygen. The most typical method is aeration of water using bubbling or injecting air into the water. This method has some unexpected ramifications though. Oxygen is only one of many gasses in air and those other gasses can be much more soluble in water. Paying attention to Henry’s Law is important here. Henry’s Law essentially means that the solubility of gasses is controlled by temperature, pressure and concentration. For example, Hayes says carbon dioxide is up to twenty times more soluble than oxygen. That means the longer you aerate water, the higher concentration of carbon dioxide and lower concentration of oxygen over time.

Another popular method of oxidizing water is chemically. Some growers might use hydrogen peroxide to add dissolved oxygen to a water-based solution, but that can create a certain level of phytotoxicity that could be bad for root health.

Using ozone, Hayes says, is by far the most effective method of getting dissolved oxygen in water, (because it is 12 ½ times more soluble than oxygen). But just using an ozone generator will not effectively deliver dissolved oxygen at the target levels to the root system. In order to use ozone properly, you need a treatment system that can handle a high enough concentration of ozone, mix it properly and hold it in the solution, says Hayes. “Ozone is an inherently unstable molecule, with a half-life of 15 minutes and even down to 3-5 minutes, which is when it converts to dissolved oxygen,” says Hayes. Using a patented control vessel, Hayes can use a counter-current, counter-rotational liquid vortex to mix the solution under pressure after leaving a vacuum. Their system can produce two necessary tools for growers: highly ozonized water, which can be sent through the irrigation system to effectively destroy microorganisms and resident biofilms, and water with high levels of dissolved oxygen for use in the root system.