Photo by Drew Taylor on Unsplash
With the recent legalization of recreational cannabis consumption in Canada, I felt it would be appropriate to bring back the conversation about the perhaps not-so-obvious potential in the cannabis industry.
Let’s start by introducing the stars of this emerging industry: the plants themselves. There has been a huge debate about the taxonomic organization of the Cannabis genus. You have likely heard about Cannabis sativa and Cannabis indica, the two alleged ‘species’ of the genus, and there is a third variant rarely heard of called Cannabis ruderalis. However, some believe that there is only Cannabis sativa, and that indica and ruderalis are strains as opposed to separate species.
Taxonomic accuracy aside, one classification has been generally accepted, and that is the distinction between marijuana and hemp. Marijuana is mostly exploited for its richness in cannabinoids, including significant amounts of the psychoactive THC, whereas hemp is popular for the production of CBD and other non-psychoactive cannabinoids, phytochemicals, and a vast diversity of industrial products. Leading to legalization we were exposed to amazing studies implicating the many health benefits the cannabis plants offer. But what else can we do with these plants?
Here are a few examples of products derived from a cannabis plant that you might not have known of before.
Foods and cosmetics
OK, this one might not come as a surprise… most of you might already be familiar with hemp products in the cereals section at the grocery store. Amongst the popular hemp foods we can find are granola products, vegan protein powders, and gluten-free flour. Hemp seeds are rich in healthy fats (including omega-3 and omega-6 fats), proteins, fibers, vitamin E and iron. And let’s not forget the incredible potential in cannabis essential oils, which can be a great source of powerful phytochemicals such as policosanols and phenolic compounds.
Similarly, the oils and nutrients in these plants are popular ingredients in cosmetic products. Whether you are looking for a nice lip balm, shampoo or moisturizing cream, the hemp plant has you covered!
Clothing
It’s hard to imagine a world where cotton is not the leading crop in the textile industry, but up until the 18th-century flax and hemp where the top players in this industry, and I believe hemp fibers are about to make a strong come-back!
More and more evidence piles up in support of hemp cultivation as a more sustainable alternative than cotton. From the physiological perspective, the hemp plant has a higher photosynthetic efficiency than the cotton plant, and it requires far less water to grow. Substituting cotton fibers for hemp fibers would not decrease the quality of the final product. A study showed that using hemp fabrics, instead of cotton fabrics or synthetic fibers, for furnishing applications is a viable alternative and I can’t see why this shouldn’t be the case for other textiles. And let’s not forget that our knowledge in plant genomics and biotechnology increases by the day, and it is likely we could improve the quality of these fibers through breeding of new hemp variants.
Construction
When I found out that hemp is used in the construction world, I was certainly surprised. It might not be news to some of you, but I got really excited reading about this, and I had to share it here.
The fibers present in the stalk of the hemp plant can be used for the formation of bio-based composites. In general terms, there are two types of fibers in the stalk: woody fibers are lignified fibers found in the core of the stalk, whereas blast fibers are found in the cortex, which can be peeled off the stalk.
A popular composite made with woody fibers is the hemp-lime composite, or as the cool kids call it, hempcrete. Hempcrete is usually less dense than cement, making it unable to support the same forces than cement, and it has outstanding thermal properties that make it ideal for insulation, even on external walls. However, high-density hemp-based composites can also resist physical and mechanical stress similar to cement, as demonstrated by researchers from the University of Bologna.
Hemp blast fibers, however, are usually used as an alternative to glass fibers. Blast fibers can be infused with epoxy resins following standard methods in the composite industry, significantly increasing the strength of the hemp-based composite, and providing a new generation of materials for applications in the construction and automotive industries. These new hemp-based composites are an excellent alternative to petroleum plastics, as they are stronger and lighter than polypropylene, a popular plastic in the automotive industry.
Bioenergy
Amongst the fibers present in the cannabis plant, you can find cellulose and hemicellulose, polysaccharides present in the cell walls of plants. Through a series of treatments, these polysaccharides can be extracted from the cannabis plant to be broken down to fermentable sugars. The woody core of hemp is composed of ≈ 40% cellulose and ≈ 35% hemicellulose, and the agricultural yield of the plant is between 2 – 18 tons per hectare. This gives a bioethanol yield of more than 80 gal/ton.
It is also possible to simultaneously obtain several sources of energy from the cannabis plant. A recent study showed that simultaneous production of 50 gal/ton of bioethanol and 115 kg/ton of succinic acid (an important chemical to synthesize polymers and used as a food additive). Similarly, another study demonstrated that co-production of bioethanol and biomethane from the whole hemp plant is feasible, yielding over 40 gal/ton of bioethanol and 175 m3/ton of biomethane (a.k.a. renewable natural gas), generating over 10 GJ of energy per ton of hemp. To put this into perspective, all the natural gas required by an average house in Canada for a year could be produced in a single hectare, while also producing bioethanol and other products from the seeds and flowers.
Insecticides and antimicrobials
Cannabis tissues have been attributed to having antimicrobial properties for some time now. A recent study has concluded that cannabis essential oil may be a good green alternative for botanical pesticides as it proved to be quite toxic to aphids, flies and leafworm larvae, although ladybugs and earthworms proved a bit more resistant. Nonetheless, this opens the possibility of using cannabis essential oils as insecticides in organic agriculture after cannabinoids have been purified.
Of course, if we are discussing antimicrobials, we have to talk about nanoparticles. Recently, scientists successfully developed silver and gold nanoparticles with antimicrobial properties, inhibiting the growth of bacteria like Pseudomonas aeruginosa and Escherichia coli. These nanoparticles were developed using an aqueous extract from hemp stems and showed excellent physical and chemical stability.
Adsorbents
From time to time we hear about toxic spills in natural environments on the news, or we read about heavy metals contaminating our lakes and groundwater. These are important problems we need to tackle, and the cannabis industry may be a great contributor to solve this.
Several products are already being developed for water remediation. For example, a hemp-based felt with a thickness of 5 mm, and a composition of 75% cellulose, 15% hemicellulose, 3% lignin, and 5% pectins, was able to remove 75-80% of metals from water, including Cd, Cu, Zn, Co, Fe, Ni, Cr, Al, and Mn.
The capacity of these fibers to adsorb heavy metals from water is very exciting, but I am actually equally as excited about the possibility to desorb metals. It has been shown that zinc ions can be recovered from contaminated sites, by adsorbing the ions onto hemp fibers and then desorbing them for recovery and reutilization. Researchers are investigating the extent to which these fibers can be used, in hopes to establish a guideline to maximize adsorption-desorption cycles.
To me, this is particularly exciting! It looks like a promising tool to recover metals that play crucial roles in our society, such as phosphorous in agriculture and zinc in batteries and electronics.
Here you can find an interesting review on hemp-based materials for the adsorption of metals.
I hope you enjoyed the brief summary of non-cannabinoid products available from the cannabis plant. Now, you might say ‘well all these examples talk about hemp.’ Yes, hemp has been a valued industrial crop for quite a while now, and keep in mind, marijuana plants have been in our industry for a shorter time, so it is possible many of the products we get from hemp could also be produced from marijuana.
With the increasing demand of cannabinoids in Canada, the cannabis industry needs to increase cultivation capacity… Why not explore all the products we can get from these plants?